ASTM C169-16(2022)

Standard Test Methods for Chemical Analysis of Soda-Lime and Borosilicate Glass

SIGNIFICANCE AND USE
3.1 These test methods can be used to ensure that the chemical composition of the glass meets the compositional specification required for the finished glass product.  
3.2 These test methods do not preclude the use of other methods that yield results within permissible variations. In any case, the analyst should verify the procedure and technique employed by means of a National Institute of Standards and Technology (NIST) standard reference material having a component comparable with that of the material under test. A list of standard reference materials is given in the NIST Special Publication 260,3 current edition.  
3.3 Typical examples of products manufactured using soda-lime silicate glass are containers, tableware, and flat glass.  
3.4 Typical examples of products manufactured using borosilicate glass are bakeware, labware, and fiberglass.  
3.5 Typical examples of products manufactured using fluoride opal glass are containers, tableware, and decorative glassware.
SCOPE
1.1 These test methods cover the quantitative chemical analysis of soda-lime and borosilicate glass compositions for both referee and routine analysis. This would be for the usual constituents present in glasses of the following types: (1) soda-lime silicate glass, (2) soda-lime fluoride opal glass, and (3) borosilicate glass. The following common oxides, when present in concentrations greater than indicated, are known to interfere with some of the determinations in this method: 2 % barium oxide (BaO), 0.2 % phosphorous pentoxide (P2O5), 0.05 % zinc oxide (ZnO), 0.05 % antimony oxide (Sb2O3), 0.05 % lead oxide (PbO).  
1.2 The analytical procedures, divided into two general groups, those for referee analysis, and those for routine analysis, appear in the following order:    
Sections  
Procedures for Referee Analysis:  
Silica  
10  
BaO, R2O2 (Al2O3 + P2O5), CaO, and MgO  
11 – 15  
Fe2O3, TiO2, ZrO2 by Photometry and Al2O3 by Com-
plexiometric Titration  
16 – 22  
Cr2O3 by Volumetric and Photometric Methods  
23 – 25  
MnO by the Periodate Oxidation Method  
26 – 29  
Na2O by the Zinc Uranyl Acetate Method and K2O by
the Tetraphenylborate Method  
30 – 33  
SO3 (Total Sulfur)  
34 – 35  
As2O3 by Volumetric Method  
36 – 40  
Procedures for Routine Analysis:  
Silica by the Single Dehydration Method  
42 – 44  
Al2O3, CaO, and MgO by Complexiometric Titration,
and BaO, Na2O, and K2O by Gravimetric Method  
45 – 51  
BaO, Al2O3, CaO, and MgO by Atomic Absorption; and
Na2O and K2O by Flame Emission Spectroscopy  
52 – 59  
SO3 (Total Sulfur)  
60  
B2O3  
61 – 62  
Fluorine by Pyrohydrolysis Separation and Specific Ion
Electrode Measurement  
63 – 66  
P2O5 by the Molybdo-Vanadate Method  
67 – 70  
Colorimetric Determination of Ferrous Iron Using 1,10
Phenanthroline  
71 – 76  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Jun-2022
• ICS: 81.040.10 - Raw materials and raw glass
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.02 - Chemical Properties and Analysis

Relations

• Refers: ASTM E50-17 - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 01-Sep-2017
• Refers: ASTM E50-11(2016) - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 01-Aug-2016
• Refers: ASTM E50-11 - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 15-Oct-2011
• Refers: ASTM C225-85(2009) - Standard Test Methods for Resistance of Glass Containers to Chemical Attack
• Effective Date: 01-Nov-2009
• Refers: ASTM C146-94a(2009) - Standard Test Methods for Chemical Analysis of Glass Sand
• Effective Date: 01-Nov-2009
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM E50-00(2005) - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 01-May-2005
• Refers: ASTM C146-94a(2004) - Standard Test Methods for Chemical Analysis of Glass Sand
• Effective Date: 01-Oct-2004
• Refers: ASTM C225-85(2004) - Standard Test Methods for Resistance of Glass Containers to Chemical Attack
• Effective Date: 01-Oct-2004
• Refers: ASTM E60-98(2004) - Standard Practice for Analysis of Metals, Ores, and Related Materials by Molecular Absorption Spectrometry
• Effective Date: 01-May-2004
• Refers: ASTM E50-00 - Standard Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• Effective Date: 10-Nov-2000
• Refers: ASTM C146-94a(1999) - Standard Test Methods for Chemical Analysis of Glass Sand
• Effective Date: 10-Apr-1999
• Refers: ASTM C225-85(1999) - Standard Test Methods for Resistance of Glass Containers to Chemical Attack
• Effective Date: 10-Apr-1999
• Refers: ASTM D1193-99 - Standard Specification for Reagent Water
• Effective Date: 10-Feb-1999
• Refers: ASTM D1193-99e1 - Standard Specification for Reagent Water
• Effective Date: 10-Feb-1999

Overview

ASTM C169-16(2022): Standard Test Methods for Chemical Analysis of Soda-Lime and Borosilicate Glass provides comprehensive procedures for determining the chemical composition of glass materials. Published by ASTM International, this standard is crucial for both manufacturers and quality assurance laboratories working with soda-lime silicate glass, soda-lime fluoride opal glass, and borosilicate glass. The methods outlined ensure that glass products meet stringent compositional specifications, a key factor for performance, safety, and regulatory compliance in various industries. Adherence to this standard supports consistency in production, quality control, and helps minimize risks related to material nonconformance.

Key Topics

ASTM C169-16(2022) covers a range of test methods for accurate, quantitative analysis of glass. Key topics include:

• Chemical Constituents: Procedures target the main oxides present in glass, such as silica (SiO₂), barium oxide, alumina, phosphorous pentoxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide, sulfur trioxide, boron oxide, and fluorine.
• Types of Analysis: Methods are divided into two categories:
  • Referee Analysis: More rigorous, detailed procedures intended for dispute resolution or confirmation of results.
  • Routine Analysis: Simplified procedures suitable for everyday quality control.
• Interfering Oxides: Guidance on the presence of certain oxides-like BaO, P₂O₅, ZnO, Sb₂O₃, and PbO-that may impact results above specific concentrations.
• Verification with NIST Reference Materials: Emphasizes the need to verify procedures with appropriate reference materials, ensuring accuracy and comparability of results.
• Equipment and Sample Preparation: Recommends best practices for crushing, grinding, and sieving glass samples, and highlights appropriate use of reagents and laboratory apparatus.

Applications

This standard is widely applied across industries where glass composition is foundational to end product quality and regulatory compliance. Practical applications include:

• Manufacturing Quality Control: Ensuring batch consistency for glass containers, tableware, flat glass, bakeware, labware, and fiberglass.
• Product Development: Confirming that new formulations meet compositional requirements for desired physical and chemical properties.
• Material Acceptance and Certification: Facilitates reliable acceptance testing between suppliers and end-users.
• Research and Failure Analysis: Provides standardized protocols for investigating glass composition during R&D and problem-solving.
• Regulatory Compliance: Assists manufacturers in meeting global product standards and trade requirements, aligning with recognized international norms.

Typical products assessed under this standard include:

• Soda-Lime Silicate Glass: Bottles, jars, windowglass, and dinnerware.
• Borosilicate Glass: Laboratory glassware, bakeware, and insulation fiber.
• Fluoride Opal Glass: Specialty containers and decorative pieces.

Related Standards

ASTM C169-16(2022) references and aligns with several other standards for comprehensive material evaluation:

• ASTM C146 - Test Methods for Chemical Analysis of Glass Sand
• ASTM C225 - Test Methods for Resistance of Glass Containers to Chemical Attack
• ASTM D1193 - Specification for Reagent Water
• ASTM E50 - Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
• ASTM E60 - Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry

For traceability and validation, practitioners are encouraged to reference the National Institute of Standards and Technology (NIST) Special Publication 260 for approved reference materials.

---

By following ASTM C169-16(2022), organizations can confidently verify glass chemical composition, control production quality, support new product development, and enhance compliance with both domestic and international standards for glass products. This ensures reliability, performance, and safety in the diverse applications that depend on soda-lime and borosilicate glass.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C169 − 16 (Reapproved 2022)
Standard Test Methods for
Chemical Analysis of Soda-Lime and Borosilicate Glass
This standard is issued under the fixed designation C169; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 These test methods cover the quantitative chemical
responsibility of the user of this standard to establish appro-
analysis of soda-lime and borosilicate glass compositions for
priate safety, health, and environmental practices and deter-
both referee and routine analysis. This would be for the usual
mine the applicability of regulatory limitations prior to use.
constituents present in glasses of the following types: (1)
1.4 This international standard was developed in accor-
soda-lime silicate glass, (2) soda-lime fluoride opal glass, and
dance with internationally recognized principles on standard-
(3) borosilicate glass. The following common oxides, when
ization established in the Decision on Principles for the
present in concentrations greater than indicated, are known to
Development of International Standards, Guides and Recom-
interfere with some of the determinations in this method: 2%
mendations issued by the World Trade Organization Technical
barium oxide (BaO), 0.2% phosphorous pentoxide (P O ),
2 5
Barriers to Trade (TBT) Committee.
0.05% zinc oxide (ZnO), 0.05% antimony oxide (Sb O ),
2 3
0.05% lead oxide (PbO).
2. Referenced Documents
1.2 The analytical procedures, divided into two general 2
2.1 ASTM Standards:
groups, those for referee analysis, and those for routine
C146Test Methods for Chemical Analysis of Glass Sand
analysis, appear in the following order:
C225Test Methods for Resistance of Glass Containers to
Sections
Chemical Attack
Procedures for Referee Analysis:
D1193Specification for Reagent Water
Silica 10
BaO, R O (Al O +P O ), CaO, and MgO 11–15 E50Practices for Apparatus, Reagents, and Safety Consid-
2 2 2 3 2 5
Fe O ,TiO ,ZrO by Photometry and Al O by Com- 16–22
2 3 2 2 2 3
erations for Chemical Analysis of Metals, Ores, and
plexiometric Titration
Related Materials
Cr O by Volumetric and Photometric Methods 23–25
2 3
MnO by the Periodate Oxidation Method 26–29 E60Practice for Analysis of Metals, Ores, and Related
Na O by the Zinc Uranyl Acetate Method and K Oby 30–33
2 2
Materials by Spectrophotometry
the Tetraphenylborate Method
SO (Total Sulfur) 34 – 35
3. Significance and Use
As O by Volumetric Method 36–40
2 3
3.1 These test methods can be used to ensure that the
Procedures for Routine Analysis:
chemical composition of the glass meets the compositional
Silica by the Single Dehydration Method 42–44
Al O , CaO, and MgO by Complexiometric Titration, 45–51
2 3 specification required for the finished glass product.
and BaO, Na O, and K O by Gravimetric Method
2 2
BaO, Al O , CaO, and MgO by Atomic Absorption; and 52–59
3.2 These test methods do not preclude the use of other
2 3
Na O and K O by Flame Emission Spectroscopy
2 2
methodsthatyieldresultswithinpermissiblevariations.Inany
SO (Total Sulfur) 60
case, the analyst should verify the procedure and technique
B O 61 – 62
2 3
Fluorine by Pyrohydrolysis Separation and Specific Ion 63–66 employed by means of a National Institute of Standards and
Electrode Measurement
Technology (NIST) standard reference material having a com-
P O by the Molybdo-Vanadate Method 67–70
2 5
ponentcomparablewiththatofthematerialundertest.Alistof
Colorimetric Determination of Ferrous Iron Using 1,10 71–76
Phenanthroline
standard reference materials is given in the NIST Special
Publication 260, current edition.
1 2
These test methods are under the jurisdiction of ASTM Committee C14 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Glass and Glass Products and are the direct responsibility of Subcommittee C14.02 contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
on Chemical Properties and Analysis. Standards volume information, refer to the standard’s Document Summary page on
CurrenteditionapprovedJuly1,2022.PublishedJuly2022.Originallyapproved the ASTM website.
in 1941. Last previous edition approved in 2016 as C169–16. DOI: 10.1520/ Available from National Institute of Standards and Technology, Gaithersburg,
C0169-16R22. MD 20899.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C169 − 16 (2022)
3.3 Typical examples of products manufactured using soda- “Medium” filter paper refers to that used for filtration of
lime silicate glass are containers, tableware, and flat glass. calcium oxalate, and “fine” filter paper to that used for barium
sulfate.
3.4 Typical examples of products manufactured using boro-
silicate glass are bakeware, labware, and fiberglass.
7. Photometers and Photometric Practice
3.5 Typical examples of products manufactured using fluo-
7.1 Photometers and photometric practice prescribed in
ride opal glass are containers, tableware, and decorative
these methods shall conform to Practice E60.
glassware.
7.2 The considerations of instrumentation given in Test
4. Purity of Reagents Methods C146 are equally applicable to these test methods.
4.1 Reagent grade chemicals shall be used throughout.
8. Preparation of Sample
Unless otherwise indicated, it is intended that reagents shall
8.1 Glass crushed in a steel mortar as described in Test
conform to the specifications of the Committee on Analytical
Methods C225, and sieved through a 150µm (No. 100) mesh
Reagents of the American Chemical Society, where such
sieve, is generally suitable for analysis, except for the deter-
specifications are available. Other grades may be used, pro-
mination of iron oxide (Fe O ). After crushing and sieving,
vided it is first ascertained that the reagent is of sufficiently
2 3
place the powder on a sheet of paper and pass a small magnet
high purity to permit its use without lessening the accuracy of
through it to remove adventitious iron. Then store in a tightly
the determination.
closed container and keep in a desiccator.
4.2 Purity of Water—Unless otherwise indicated, reference
8.2 A sample prepared in an iron mortar is not recom-
to water shall be understood to mean reagent water as defined
mended for the determination of Fe O . Instead, glass should
by Type I, II, or III of Specification D1193.
2 3
be ground in an agate mortar after ascertaining it is free of
contamination.
5. Concentration of Acids and Ammonium Hydroxide
5.1 When acids and ammonium hydroxide are specified by 8.3 A sample prepared for the determination of fluorine
should be sieved through a 75µm (No. 200) mesh sieve rather
name or chemical formula only, concentrated reagents of the
following percent concentrations are intended: than a 150µm (No. 100) sieve.
%
8.4 The practice of drying samples in a drying oven at
Hydrochloric acid (HCl) 36 to 38
105°C to 110°C after preparation is not recommended.
Hydrofluoric acid (HF) 48 to 51
Powdered glass can fix CO and water as readily at this
Nitric acid (HNO ) 69to71
Perchloric acid (HClO ) 70to72
temperatureasatroomtemperature.Afreshlypreparedsample,
Sulfuric acid (H SO ) 95to98
2 4
if exposed but a short time to the atmosphere, will not have
Ammonium hydroxide (NH OH) 28 to 30
acquired an ignition loss of much analytical significance. If
ignition loss is determined, use the following temperature
5.2 Concentrations of diluted acids and NH OH except
schedules:
when standardized are specified as a ratio, stating the number
of volumes of the concentrated reagent to be added to a given
Soda-lime glass 800 °C for 1 h
number of volumes of water, as follows: HCl (1 + 99) means
Fluorine opal glass 500 °C to 550 °C for 1 h
1 volume of concentrated HCl (approximately 37%) added to
Borosilicate glass 800 °C for 1 h
99 volumes of water.
Determine the ignition loss on a 1g to 3g sample in a
5.3 The hygroscopic nature of the ignited precipitates of
platinum crucible.
silica, aluminum oxide, and calcium oxide obtained in the
methods to be described, requires the use of fresh and highly
9. Precision and Bias
active desiccants. For this purpose, magnesium perchlorate
9.1 The probable precision of results that can be expected
(Mg(ClO ) ) and barium oxide (BaO) are recommended.
4 2
by the use of the procedures described in these test methods is
6. Filter Papers shown in the following tabulation. Precision is given as
absolute error, and is dependent on the quantity of constituent
6.1 Throughout these test methods, filter papers will be
present as well as the procedure used.
designated as “coarse,” “medium,” or “fine,” without naming
Probable Precision of Results, weight %
brandsormanufacturers.Allfilterpapersareofthedoubleacid
washedashlesstype.“Coarse”filterpaperreferstotheporosity
Constituent Referee Analysis Routine Analysis
commonly used for the filtration of aluminum hydroxide.
Silica ±0.1 ±0.25
BaO ±0.02 ±0.05
Al O +P O ±0.05 ±0.10 (−P O )
2 3 2 5 2 5
CaO ±0.05 ±0.15
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
MgO ±0.05 ±0.02 to 0.10
Standard-Grade Reference Materials, American Chemical Society, Washington,
Fe O ±0.003 . . .
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical 2 3
TiO ±0.005 . . .
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
ZrO ±0.001 to 0.005 . . .
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
Cr O (volumetric) ±0.005 . . .
2 3
copeial Convention, Inc. (USPC), Rockville, MD.
C169 − 16 (2022)
Cr O (photometric) ±0.0001 to 0.001 . . . Percent Number of Significant Figures
2 3
MnO ±0.001 to 0.005 . . . Retained After Rounding
Na O ±0.05 ±0.25 (flame emission) 1to100 3
K O ±0.02 to 0.05 ±0.02 to 0.10 (flame emission) 0.1to0.99 2
SO ±0.02 ±0.05 0.01 to 0.09 1 or 2
As O ±0.005 . . . <0.01 1 or 2
2 3
P O . . . ±0.005 to 0.02
2 5
9.3 Recorded results should be carried to one more signifi-
B O . . . ±0.05 to 0.15
2 3
Fluorine . . . ±0.01 to 0.20 (0.1 to 6.0 %)
cant figure than required in 9.2.
9.2 It is recommended that reported results be rounded as
follows:
PROCEDURES FOR REFEREE ANALYSIS
SILICA stirring rod and the periphery of the funnel with a piece of
damp filter paper and add to the dish containing the precipitate
for ignition.
10. Procedure
10.1 Weigh 1.000 g of powdered sample and 1.5 g of NOTE 1—Glasses containing fluorine in small amounts (less than
0.25%)willnotcausesignificanterror.Glassescontaininglargeramounts
anhydrous sodium carbonate (Na CO ) for soda-lime glass, or
2 3
of fluorine (for example, fluoride opals) are analyzed as above with this
2.0g of Na CO for borosilicate glass, into a clean 75mL
2 3
exception: after the fusion has been made and before addition of the acid
platinum dish (see 10.1.1); mix well with a platinum or
(see 10.2), add 10 mL of aluminum chloride (AlCl ) solution
Nichrome wire. Tap the charge so it lies evenly in the bottom
(10mL=200 mg ofAl) to complex fluorine. If evaporation is made on a
steambath,itisdifficulttodrytheresidue.Itissuggestedthatfinaldrying,
of the dish. Cover with platinum lid and heat first at a dull red
before filtration, be made in a drying oven for 30 to 45 min at 105°C.
heat over a clean oxidizing flame; gradually raise the tempera-
Results for SiO when analyzing fluorine opals may tend to be low by
ture until a clear melt is obtained. Properly carried out, little or
0.2% to 0.3%. For an alternative, but more lengthy procedure, consult
no spattering should occur and the fusion can be performed in
Applied Inorganic Analysis.
3 to 4 min. When melted, rotate the melt to spread it evenly
NOTE 2—Boron in amounts less than 5% B O does not interfere.
2 3
However, if boron is greater than 5%, proceed to the point of completing
over the bottom and lower sides of the dish, gradually
the first dehydration (see 10.2), then add 20 mL of anhydrous methanol
withdrawing from the flame. Cover and cool to room tempera-
saturated with dry HCl (gas), and evaporate to dryness on an air bath or
ture.Duringfusion,thedishshouldbehandledatalltimeswith
under an infrared lamp. Repeat once more before proceeding.
platinum-tipped tongs and the fusion performed with a plati-
10.3 Evaporate the filtrate to dryness on the steam bath or
num (preferably 90% platinum and 10% rhodium alloy) or
under an infrared lamp.When dry, cool, drench with 10 mLof
silica triangle.
HCl (1+1) and again evaporate just to dryness; then bake in a
10.1.1 To obtain accurate repeat weighings, platinum ware
drying oven at 105°C for 30 min. Cool, drench with 5 mL of
shall be kept scrupulously clean on the outside of the vessel as
HCl, and add 20 mLof hot water and a small bit of filter pulp.
well as on the inside. It should be polished brightly with fine,
Digesthotfor5minandfilterthrougha7cmfinepaper.Police
round grain sand and protected from dirty surfaces. It is
thedishwiththeaidofabitofpaperpulpandwashprecipitate
recommendedthatporcelainplatesbeusedforcoolingfusions,
andpapereighttimeswithhot2%HCl.Transferthepaperand
andthatplatinumbesetonpapertowelsorothercleanmaterial
precipitate to the dish containing the initial precipitation.Wipe
during filtration.
the stirring rod and the periphery of the funnel with a piece of
10.2 Add 20mL to 25 mL of HCl (1 + 1) (Note 1) under
damp filter paper and add to the dish containing the precipitate
theplatinumcoveranddigestonasteambathorhotplateuntil
for ignition.
the melt has completely disintegrated; it is also possible to
10.4 Partially cover the dish with its platinum lid but leave
digest the melt in the cold overnight. Police and rinse the lid
enoughspacesoaircancirculateduringignition.Placethedish
with a fine jet of water; rinse down the sides of the dish and
in a cold muffle furnace and bring the temperature to 1200°C
evaporatetodrynessonasteambathorunderaninfraredlamp.
for 30 min. Carefully and completely cover the dish before
Keep the dish covered with a raised cover glass during
removing it from the furnace and transfer to a desiccator. Cool
evaporation. When evaporation is complete (Note 2) (absence
toroomtemperatureandweighthecovereddish(W ).Moisten
of HCl), cool, drench the residue with 5 mL of HCl, and then
the silica with 1mL to 2 mL of water and add 4mL to 5 mL
add 20 mL of hot water. Digest for 5 min and filter through a
ofHFand0.5gofoxalicacidcrystals.Evaporatetodrynesson
9cm medium filter paper. Catch the filtrate in a 250mL
a sand bath or under an infrared lamp. Carefully sublime any
platinum dish. Transfer the precipitated silica to the filter with
remaining oxalic acid, cover the dish with its platinum cover,
the aid of a policeman and a bit of paper pulp, and wash the
heat to 1000°C for 2 min, cool, and weigh (W ) as before.
precipitate and paper twelve times with hot 2% HCl. Transfer
10.5 Calculation—Calculate the percent of SiO as follows:
the paper and precipitate to the dish used for fusion and
dehydration and reserve for subsequent ignition. Wipe the
SiO,% 5 ~W 2 W ! 3100 (1)
2 1 2
Hillebrand, Lundell, Bright, and Hoffman, Applied Inorganic Analysis, John
Trademark of the Driver-Harris Co., 308 Middlesex St., Harrison, NJ 07029 Wiley & Sons, Inc., New York, NY, 1953, pp. 943–944.
C169 − 16 (2022)
BaO, R O (Al O +P O ), CaO, AND MgO 1mLto2mLofHNO ; evaporate to dryness. Cool, add 5 mL
2 3 2 3 2 5 3
of HCl and 20mLof hot water, digest to disintegrate the salts,
11. General Considerations
transfer to a 250mLbeaker, dilute to 150 mL, and boil gently
11.1 Thedetailedanalysisdescribedbelowmaybedesirable
for about 5min to dissolve all sulfates except barium. (In the
only infrequently. Several steps may be omitted without undue
absence of barium, proceed directly to precipitation with H S
loss of accuracy, for example, the hydrogen sulfide (H S) and
or NH OH.) When all sulfates have dissolved except barium,
thecupferronprecipitations.Manyglassescontaininsignificant
adjust the acidity by neutralizing with NH OH (using methyl
amountsofBaO(lessthan0.1%),inwhichcaseBaOalsomay
red as the indicator) and reacidify with 1 mLof HCl.Add 3 to
be ignored. Thus, if the separation of BaO and the H S
4 drops of H SO and digest hot for 30 min; cool for2hand
2 2 4
precipitation are bypassed, the analysis can begin with the
filter through a fine 7cm paper into a 400mL beaker. Police
ammonia precipitation of the R O group. Frequently, correc-
the beaker with the aid of a bit of paper pulp and wash 4 to 5
2 3
tion of the R O for Fe O , titanium dioxide (TiO ), and
times with cold water containing a few drops of H SO .
2 3 2 3 2
2 4
zirconium oxide (ZrO ) will allow a useful estimation of the
Reserve the filtrate (A). Proceed to 12.2.
remainder as aluminum oxide (Al O ); phosphoric anhydride
2 3
NOTE 3—An alternative procedure may be used to prepare the sample
(P O )isusuallysmall(lessthan0.02%).However,ifchromic
2 5
by first evaporating with HF alone. If evaporation is done at a moderate
oxide (Cr O ) is present, it will be counted as Al O ; for
heat, it has the advantage of being allowed to proceed unattended. When
2 3 2 3
example, in some green glasses, Cr O may be as much as thefluorideresidueisdry,coverthedishwithaplatinumlidsoastoallow
2 3
sufficient space for vapors to escape. Add 10mL to 12 mL of HClO or
0.25%. H SO is preferred to HC1O in sample preparation
2 4 4
5mLto6mLofH SO (1+1) underneath the lid, return to the source of
2 4
when Cr O is present (0.01% to 0.25%). The scheme of
2 3
heat, and after all fluorides have reacted, and mild fuming of HClO or
analysis is the same with either acid, except that BaO (if
H SO has begun (usually in 10 min), cool, rinse the lid and sides of the
2 4
present) must be precipitated when HClO is used, whereas it
dish with water, and continue the evaporation as described in 12.1.1 or
12.1.2.
is rendered insoluble with the use of H SO .
2 4
12.2 Transfer the BaSO precipitate (12.1.1 or 12.1.2)toa
12. Determination of BaO
smallplatinumcrucible,charandigniteat700°Cto800°Cfor
12.1 Prepare the sample by using one of the following two
approximately30min.Cool,add0.5gto1.0gofNa CO ,mix
2 3
methods:
well with the flattened end of a glass rod, and fuse at a
12.1.1 Using HClO —Weigh 2.000 g of sample into a
moderateheatfor5to10min.Cool,add10mLto15mLofhot
75mL or 100mL platinum dish, moisten with 5 mL of water,
water,anddigestuntilthemelthascompletelydissolved.Filter
and add 10mLto 12 mLof HF and 12mLto 15 mLof HClO
into a 100mLbeaker through a 7cm medium paper and wash
while stirring with a platinum or plastic rod. Evaporate
4 to 5 times with cold 0.5% Na CO solution. Reserve the
2 3
uncovered until fluorides begin to react, then cover with a
filtrate (B).
platinum lid, allowing just sufficient space for HF to escape.
12.3 Cover the funnel and place a 150mL beaker under it;
When all reaction has subsided, cool, rinse off the lid and the
dissolve the carbonate precipitate with hot 5% HCl. Rinse the
sidesofthedish,stir,andevaporatetostrongfumesofHClO .
platinum crucible, cover with hot 5% HCl, and pour through
Cool, rinse down the sides of the dish, add 5 mL of saturated
the filter. Wash the paper 4 to 5 times with hot 5% HCl.
boric acid (H BO ) solution, and evaporate to near dryness.
3 3
Discard the paper. Neutralize the filtrate (using methyl red as
Cool, and add 20 mL of water and 1 mL of HCl. Digest until
the indicator) with NH OH, reacidify with 1 mL of HCl, and
saltshavedissolvedandtransfertoa250mLbeaker.Ifasmall
dilute to 100 mL. Heat to near boiling; add dropwise with
amount of insoluble material remains, police the dish and
stirring5mLof10%ammoniumsulfate((NH ) SO )solution
4 2 4
transfer any residue to the beaker. (In the absence of barium,
or1mLofH SO (1 + 1).Digestnearboiling30min;coolfor
2 4
proceed directly to precipitation with HSorNH OH.) Dilute
2 4
2 h. Filter through a 7cm fine paper; police the beaker with a
to 100 mL and heat to a gentle boil. Precipitate barium by the
bitofpaperpulp.Wash5to6timeswithcoldwatercontaining
slow addition of 10 mL of a 10% solution of (NH ) SO or
4 2 4
a few drops of H SO . Reserve the filtrate (C).
2 4
2mLofH SO (1 + 1). Digest near boiling for 1 h, cool, and
2 4
12.4 Transfer the paper and precipitate to a tared crucible,
allow to stand for 2 h. Filter through a 7cm fine paper into a
400mL beaker; police the beaker in which the precipitation charcarefullyandigniteat800°Cto1000°Cfor30min.Cool
was made with the aid of a bit of filter paper pulp. Wash 4 to in a desiccator and weigh as BaSO .
5 times with cold water containing a few drops of H SO .
2 4
12.5 Calculation—Calculate the percent of BaO as follows:
Reserve the filtrate (A). Proceed to 12.2.
BaO,% 5wt 30.657 3100/2 (2)
12.1.2 Using H SO —Weigh 2.000 g of the sample into a
2 4
75mL or 100mL platinum dish, moisten with 5 mL of water,
13. Determination of R O by Ammonium Hydroxide
2 3
and add 12mL to 15 mL of HF, 5mL to 6 mL of H SO
2 4
Precipitation and Estimation of Al O :
2 3
(1 + 1),and,ifCr O ispresent,5to10dropsofH SO while
2 3 2 3
stirring with a platinum or plastic rod. Evaporate uncovered 13.1 Determination of R O :
2 3
until fluorides begin to react, then cover with a platinum lid, 13.1.1 Acidify the reserved Na CO filtrate (B) (using
2 3
allowing just sufficient space for HF to escape. When the methylredandHCl)(see12.2).Reducethevolumeofallthree
reactionhassubsided,cool,rinseoffthelidandthesidesofthe reserved filtrates (A, B, and C) (see 12.1.1 or 12.1.2, 12.2, and
dish, and evaporate to strong fumes of H SO . Cool, rinse 12.3) and combine them so that the total volume is about
2 4
down the sides of the dish, add 2 mL of saturated H BO and 200mL. Adjust the acidity to about 1% HCl with NH OH.
3 3 4
C169 − 16 (2022)
Addabout3mgto5mgofcopperasCuCl (asacarrier),heat 13.2.3 Calculation—Calculate the percent of Fe O,TiO ,
2 2 3 2
to near boiling, and precipitate by passing H S through the ZrO , and V O as follows:
2 2 2 5
solution as it cools. Filter through a 7cm medium paper into a
Fe O , TiO , ZrO ,V O ,% 5wt 3100/2 (4)
2 3 2 2 2 5
400mLbeaker, and wash 4 to 5 times with 1% HCl saturated
13.3 Estimation of Al O —The percent of R O , (see 13.1)
2 3 2 3
with H S. Discard the precipitate. Boil the solution to expel
minus the percent of oxides found by the cupferron precipita-
H S, add 3mLto 4 mLof saturated bromine water, and boil to
tion(see13.2),isanestimationofAl O +P O (andCr O,if
2 3 2 5 2 3
expel bromine.
present). The percent of Al O is more closely estimated by
2 3
13.1.2 Precipitate the R O by adding NH OH dropwise
2 3 4
subsequently determining P O and Cr O and deducting the
2 5 2 3
usingmethylredindicator,add3or4dropsinexcess,andboil
percentsfound.TheestimateofAl O mayalsobeobtainedby
2 3
gently for 1 to 2 min. Filter through a 9cm coarse paper into
subtracting the percent of Fe O , and so forth, determined
2 3
a 600mL beaker (it is not necessary to police the beaker).
separately (see Sections16–29) from the R O .
2 3
Allowtheprecipitatetodrainandwash3timeswithhotneutral
(methyl red) 2% NH Cl. Reserve the filtrate (D).
14. Determination of CaO
13.1.3 Transfer the precipitate to the beaker in which it was
14.1 Procedure:
precipitated, and add 10 mL of HCl (1 + 1). Stir the paper to
14.1.1 Slightly acidify (using HCl) the filtrates (D and E)
a pulp and warm to dissolve the hydroxides. Dilute to 175mL
from the R O precipitation (see 13.1), evaporate to about
to 200 mL, heat to boiling, and repeat the precipitation with
2 3
100mL each, combine the filtrates, and make to a volume of
NH OH as before. Filter through an 11cm coarse paper into a
about 225 mL in a 400mL beaker. Heat to near boiling; add
600mL beaker. Carefully police the beaker with a bit of filter
NH OHdropwiseinexcessofabout6drops.Add20mLofhot
pulp, allow the precipitate to drain, and wash 4 to 5 times with 4
10% ammonium oxalate and then stir as the solution is
hot 2% NH Cl as before. Washing and filtration may be
brought to a gentle boil. Digest hot for 15 min, cool to room
facilitated by the aid of gentle suction and a platinum filter
temperature, and after 30 min, filter on a 9cm medium paper.
cone. Reserve the filtrate (E).
It is not necessary to police the beaker.Wash 2 to 3 times with
13.1.4 Transfer paper and precipitate to a clean, tared
cold 0.1% ammonium oxalate solution. Reserve the filtrate
platinum crucible with lid. Partially cover the crucible with its
(F).
lid but leave enough space for air to circulate during ignition.
14.1.2 Dissolve the precipitate from the paper into the
Place the crucible in a cold muffle furnace and bring the
beakerusedfortheinitialprecipitationusinghotHCl(1 + 4).
temperature to 1200°C for 30 min. Cover the crucible before
Alternately wash three times each with hot water and hot HCl
removing from the furnace. Cool over a good desiccant and
(1 + 4) and dilute to about 200 mLwith hot water.Add 2.0 g
weigh.
of ammonium oxalate and several drops of methyl red indica-
13.1.5 Calculation—Calculate the percent of R O as fol-
2 3
tor. Then add NH OH until the precipitate that is forming just
lows:
dissolves, heat to near boiling, and add NH OH (1 + 1)
R O ,% 5wt 3100/2 (3)
dropwise(preferablyfromaburet),stirringuntilthesolutionis
2 3
slightly ammoniacal (about 10 drops in excess). Digest near
(R O includes Al O,Fe O,TiO , ZrO,V O,Cr O ,
2 3 2 3 2 3 2 2 2 5 2 3
boiling for 15 min and cool to room temperature for 30 min.
P O , and traces of other elements not precipitated by H S and
2 5 2
Filterona9cmmediumpaperandpolicethebeakerwithabit
precipitated by NH OH.)
of paper pulp. Wash the precipitate six times with cold 0.1%
ammonium oxalate solution. Reserve the filtrate (G).
13.2 Determination of Total of Fe O ,TiO , ZrO , and V O
2 3 2 2 2 5
with Cupferron: 14.1.3 Transfer the precipitate to a tared platinum crucible
with cover and finally ignite at 1100°C for 30 min. Cover the
13.2.1 Add approximately5gof potassium pyrosulfate
crucible before removing from the furnace. Cool over a good
(K S O ) to the crucible and precipitate and fuse until a clear
2 2 7
desiccant and weigh.
meltisobtained.Fusionshouldbecarriedoutatlessthanared
heat; otherwise, the pyrosulfate will decompose rapidly and
14.2 Calculation—Calculate the percent of CaO as follows:
some attack of the platinum will occur. When the fusion is
CaO,% 5wt 3100/2 (5)
complete, rotate the crucible so the mass solidifies on the sides
of the crucible. Cover, cool, add 20 mL of water and a few
15. Determination of MgO
drops of H SO , and digest until the melt has dissolved.
2 4
15.1 Procedure:
13.2.2 Transfer to a 250mL beaker, cool, add 10 mL of
H SO , dilute to 100 mL and cool in ice water to 10°C. Add 15.1.1 Slightly acidify the two filtrates (F and G) from the
2 4
2mL of cold 6% solution of cupferron while stirring, add precipitation of calcium (see Section 14), evaporate to a
some paper pulp, and let set for 5 min with occasional stirring. volume of about 100 mLeach, and combine. Cool and add 2 g
Filter through a 9cm medium paper, police the beaker with a of dibasic ammonium phosphate ((NH ) HPO ).Add NH OH
4 2 4 4
bit of paper pulp, and wash eight times with cold 10% H SO slowlywhilevigorouslystirringthesolutionwithapoliceman-
2 4
containing 1.5 g of cupferron per litre. Discard the filtrate, tippedroduntilthesolutionisapproximately10%ofNH OH.
transfertheprecipitateandpapertoataredcruciblewithcover, If precipitation is extremely slow, continue stirring until a
dry at 60°C, cautiously char, and finally ignite at 1000°C for precipitate forms. Allow the precipitate to settle overnight.
30min. Filterona9cmor11cmfinefilter(itisnotnecessarytopolice
C169 − 16 (2022)
the beaker at this time). Wash 3 to 4 times with cold NH OH inapolyethylenebottle.Itisusuallypracticaltoprepare2Lto
(1 + 40); discard the filtrate. 4Latatime.Onemillilitrewillcomplexapproximately1.0mg
of AlO .
15.1.2 Dissolve the precipitate with hot HCl (1 + 9) into a
beaker used for precipitation. Wash the paper three times each
17.2 EDTA Solution(EthylenediaminetetraaceticAcidDiso-
alternately with hot water and hot HCl (1 + 9). Rinse down
diumSalt)—Dissolve7.3gofEDTAinwateranddiluteto1L;
the sides of the beaker with the acid wash solution. Cool, add
store in a polyethylene bottle. One millilitre will complex
0.1gof(NH ) HPO ,anddiluteto100mLforsmallquantities
4 2 4 approximately 1.0 mg of Al O . This solution may be used
2 3
of precipitate (less than 1 % MgO); or add 0.2 g of
instead of a CDTA solution.
(NH ) HPO and dilute to 200 mL for larger quantities.
4 2 4
17.3 Ethyl Alcohol, Absolute (Anhydrous)—100% or 200
Neutralize with NH OH and then slightly reacidify. Add
proof reagent quality.
NH OH (1 + 1) dropwise from a buret while stirring the
17.4 Ferric Oxide Standard Solution (1 mL=0.1 mg
solution until precipitation appears complete. Add NH OH
Fe O )—Weigh 0.4911 g of reagent ferrous ammonium sulfate
until the solution is 5%. Let stand4hor overnight. Filter on
2 3
into a 1L volumetric flask, dissolve in water, add 8mL to
a 9cm or 11cm fine paper, and police the beaker and stirring
10mLofHCl,dilutetovolume,andmix.Thefactthattheiron
rod with the aid of a little paper pulp, making sure all
may slowly oxidize is of no consequence as it is subsequently
precipitate adhering to the beaker is removed. Wash 6 to 8
reduced when developing the 1,10-phenanthroline complex.
timeswithcoldNH OH(1 + 40)solution;discardthefiltrate.
15.1.3 Transfer the precipitate to a tared platinum crucible,
17.5 Hydrochloric Acid, Dilute(1+4)—Dilute 1 volume
place in a cold muffle furnace and raise the temperature to
ofHCl(approximately37%)with4volumesofwater.Prepare
1000°C; ignite for 1 h. Cool in a desiccator and weigh.
2L.
17.6 Hydroxylamine Hydrochloride (10% weight per vol-
NOTE 4—Manganese, if present in the glass, will be found in the
magnesiumprecipitateandshouldbecorrectedaccordingly,ifgreaterthan ume in water)—Filter if necessary.
0.01%. Also, any barium, calcium, and R O escaping prior separations
2 3
17.7 Nitric Acid, Dilute(1+1)—Dilute1volumeofHNO
will be found in the precipitate. Thus, prior separations should be as
(approximately 70%) with 1 volume of water. Prepare 2L.
complete as possible.
NOTE 5—MgO in amounts less than 0.25% can be determined more
17.8 1,10-Phenanthroline Solution—The solution may be
conveniently and as accurately by atomic absorption spectroscopy (see
prepared from the monohydrate or hydrochloride. The latter is
Sections52–59).
readily water-soluble; the monohydrate requires heating. Dis-
15.2 Calculation—CalculatethepercentofMgOasfollows:
solve 1.2 g of the monohydrate by adding to 800 mL of hot
water; stir and heat until in solution, cool and dilute to 1L;
MgO,% 5wt 30.3622 3100/2 (6)
store in a dark bottle or in a dark place. If the hydrochloride is
Fe O ,TiO , and ZrO BY PHOTOMETRY AND
2 3 2 2 used, dissolve 1.3 g in 200mL to 300 mL of water and dilute
Al O BY COMPLEXIOMETRIC TITRATION
2 3
to 1L; protect from light during storage. Five millilitres of
either solution will complex 0.6 mg of Fe O (10 mL will
2 3
16. General Considerations
complex1.2mg).Thiswillcoveratransmittancecurveoffrom
100% Ttoabout12%to17%,dependingoninstrumentation.
16.1 Instead of the classical extended analysis of the R O
2 3
The absorbance for 0.6 mg of Fe O in 100 mLvolume equals
2 3
precipitate, direct colorimetric determinations of Fe O,TiO ,
2 3 2
approximately 0.825 in a 1cm absorption cell.
and ZrO are applied. Because of the low percentages usually
encountered, these methods are appropriate. Generally, com- 17.9 Pyridine, Analytical Reagent.
mercial glasses will range from 0.02% to 0.25% for Fe O ;
2 3
17.10 Pyrocatechol Violet—Prepare a 0.05% w/v solution
from 0.02% to 0.05% for TiO ; and from 0.005% to 0.05%
in absolute ethyl alcohol by dissolving 12.5 mg of reagent in
for ZrO . The complexiometric determination of Al O is
2 2 3
25mLofabsolutealcohol.Thesolutionmustbeprepareddaily
accurateandentirelysatisfactoryasaroutineprocedure,andas
just before use. The reagent should be tested for sensitivity
a check on the classical gravimetric method.
before use. Test the reagent with a known quantity of ZrO as
described in Section 21 and if the absorbance or present
16.2 Toavoidthecontaminationthatinevitablyresultsfrom
transmittance indicated in 21.4 is not obtained, discard the lot
crushing glass in a steel mortar, clean pieces of glass must be
of reagent and obtain a fresh lot for further use.
found in an agate mortar (alumina mortars are unsatisfactory).
If the pieces chosen for grinding are suspected of
17.11 Sodium Acetate (Buffer) Solution (2 M)—Dissolve
contamination, soak in hot HCl (1 + 1) for 10 min, rinse with
272 g of sodium acetate (CH COONa·3H O) per litre of
3 2
distilled water, and dry.
aqueoussolutionprepared.Filterbeforeuseifnecessary.Since
sodium acetate solutions tend to develop mold growth with
17. Reagents
age, a preservative can be used; 0.025 g of para-
chlorometaxylenolperlitrehasbeenfoundsatisfactoryforthis
17.1 CDTA Solution (1,2-Cyclohexylene Dinitrilo) Tet-
purpose.
raaceticAcid)—Dissolve7.3gofCDTAin200mLofwaterby
the slow addition of 20% weight per volume NaOH solution 17.12 Thioglycolic Acid (CH SHCOOH, Reagent, Assay
with stirring. When the reagent has dissolved, adjust the pH to 96% to 97%)—Prepare a 20% volume solution; keep refrig-
7 with HCl (1 + 10) using a pH meter, dilute to 1 L, and store erated.
C169 − 16 (2022)
17.13 Tiron Reagent (Disodium-1,2-di-Hydroxybenzene-3, 18. Procedure
5-Disulfonate)—Prepare a 5% weight per volume solution.
18.1 Grindcleanpiecesofsampleinanagatemortarsothat
Filter if necessary. The solution should be nearly colorless.
thecoarsestpieceswouldpassa150µm(No.100)meshsieve.
Protect from light in storage.
Weigh 2.000 g of the ground sample into a 75mL or 100mL
platinum dish, moisten with 5 mLof water, and, while stirring
17.14 Titanium Dioxide, Standard Solution (1 mL=1.0 mg
with a platinum or plastic rod, add 12mLto 15 mLof HF and
TiO )—Weigh 1.0026 g of NIST SRM No. 154b titanium
12mL to 15 mL of HClO . Evaporate until fluorides begin to
dioxide, and prepare 1 L of solution as directed by the
react, then cover with a platinum lid, allowing just sufficient
certificate furnished with the material for use as a standard for
space for HF to escape. When all reaction has subsided, cool,
colorimetry.(Ifanoldersupply,Nos.154or154a,isavailable,
rinse the lid and sides of the dish, stir, and evaporate to strong
use the appropriate weight as determined from the certified
fumes of HClO . Cool, rinse down the sides of the dish, add
percent of TiO .)
5mL of saturated H BO solution, and evaporate to dryness.
3 3
17.15 Titanium Dioxide, Dilute Standard Solution
Eventually, partially cover the dish to remove the last traces of
(1mL=0.1 mg TiO )—Pipet 50 mL of the 1.0 mg TiO /mL excessHClO .However,donotprolongheating,asbasicsalts,
2 2 4
standardsolutionintoa500mLvolumetricflask,add15mLof difficult to dissolve, can result. Cool, add 10 mL of HCl
H SO , and dilute to about 400 mL; mix by swirling. Cool to (1 + 4), and digest warm until the salts are in solution (see
2 4
18.1.1 and Note 6).Transfer or filter the sample solution into a
room temperature, if necessary; dilute to volume and mix.
100mLvolumetric flask; cool and dilute to volume. Prepare a
17.16 TOPO Reagent (tri-n-Octyl-Phosphine Oxide)—
reagent blank; aliquots identical to those for the separate
Prepare an approximately 0.01 M solution by dissolving1gof
determinations are used as photometric references.
reagent in 200mL of cyclohexane.
18.1.1 If a slight cloudiness persists at this point, it is
probably a precipitate of barium sulfate (BaSO ). In this case,
17.17 Xylenol Orange Tetrasodium Salt (Indicator)
add a bit of paper pulp, dilute to about 35mL to 40 mL, cool
Solution—Dissolve 0.5 g in 100 mL of water, and add 1 or 2
for about 30 min, and filter through a 5.5cm or 7.0cm fine
drops of HCl as stabilizer.
filter into the volumetric flask. Wash moderately twice with
17.18 Zinc Standard Solution—Prepare from ACS reagent
cold water, once with 2 mL of HCl (1+4), and twice more
or spectroscopically pure metal freed of oxide surface film.
with water. If a predetermined amount of sodium acetate is to
Dissolve1.283gofmetalin30mLofHCl(1 + 4),anddilute
be used to adjust the pH for determination of Fe O , the
2 3
to 2 L with water. One millilitre of Zn solution=0.500 mg of
amount taken shall accommodate an aliquot taken from a
Al O andapproximately0.50mLofCDTAorEDTAsolution.
2 3
sample volume containing 12 mL of HCl (1+4) rather than
Since the zinc solution is the standard for the Al O
2 3
10mL.
determination, it must be prepared with care and accuracy.
NOTE 6—Sample preparation with HClO will oxidize Cr(III) to
17.18.1 Standardization of CDTA or EDTA Solution with
Cr(VI); hexavalent chromium will interfere in both the determination of
Standard Zinc Solution—Accurately pipet 10mL or 15 mL of
ZrO and in the end point detection of the Al O titration. To reduce
2 2 3
CDTA or EDTA solution to a 150mL or 250mL beaker and hexavalent chromium (apparent by the orange to reddish color of the
perchloratesalts),transferthesolutionfromtheplatinumdishtoa150mL
dilute to about 40mL to 50 mL. Add 5 mL of 2 M sodium
beaker,diluteto50mL,add7%sulfurousacidreagentdropwiseuntilthe
acetate buffer and while stirring on a magnetic stirrer, adjust
chromium has been reduced to Cr(III), and boil gently for about 5 min to
the pH to 5.3 by the addition of acetic acid using a pH meter,
remove excess SO . If the solution is cloudy, proceed as in 18.1.1;
orbyusingxylenolorangeasapHindicator(Note8in22.3.1). otherwise, transfer directly to the volumetric flask.
Titrate with the standard zinc solution to the first perceptible
18.2 Adjustment of pH—The procedures in this section
colorchangefromyellowtopinkish-red.Acircleoffilterpaper
specify adjustment of pH by the use of 2 M sodium acetate
placed under the beaker will aid in detecting the end point.
solution alone.This may be accomplished accurately by use of
Repeat at least twice more and average the titers. Millilitres of
a pH meter. It may also be done conveniently when numerous
zinc solution divided by millilitres of CDTA or EDTA equals
samples are repetitiously analyzed by predetermining the
millilitres of zinc equivalent of CDTA or EDTA.
quantity of 2 M sodium acetate solution required as follows:
prepare a solution of 10 mLof HCl (1 + 4) diluted to 100 mL
17.19 Zirconium Oxide, Standard Solution (1 mL=0.1 mg
in a volumetric flask. Pipet the quantity of sample solution to
ZrO )—Standardize reagent quality zirconyl nitrate by careful
be taken as specified (usually 25 mL) into a 150mL beaker,
ignition to the oxide as follows: accurately weigh 2.0 g of the
dilute to 35mL to 40 mL, and with a pH meter, record the
nitrateintoataredplatinumdishorcrucibleandgraduallyheat
volumeof2 Msodiumacetatesolutionaddedfromaburetthat
from room temperature to 1000°C. Weigh a sufficient amount
is required to bring the pH to 3.2 (for Fe O andAl O ).Add
2 3 2 3
of the standardized nitrate to make 1 L of solution containing
2mL of 20% thioglycolic acid, 5 mL of Tiron, and then
0.1mgofZrO /mL.Transfertoa1Lvolumetricflask,dissolve
additional 2 M sodium acetate solution until the pH is 4.5;
in HNO (1 + 1), and dilute to volume with HNO (1 + 1).
3 3
record for use in the determination of TiO . The pH specified
17.20 Zirconium Oxide, Dilute Standard Solution
in the several procedures is near optimum. The use of other
(1mL=20 µg ZrO )—Dilute 100 mL of the 0.1 mg ZrO /mL buffer solutions is permissible but it is recommended that their
2 2
standard solution to 500 mL in a volumetric flask with HNO
use be checked by pH measurement to determine that the
(1 + 1). specified pH is obtained.
C169 − 16 (2022)
19. Iron Oxide by 1,10-Phenanthroline Method volume,andmix.After15min,measureabsorbanceorpercent
transmittance as described in 21.2. Plot the readings as
19.1 Transfer a suitable aliquot, not to exceed an equivalent
described for Fe O (see 19.4). The absorbance for 0.3 mg of
2 3
of 0.5 g (25 mL), nor containing more than 0.6 mg of Fe O ,
2 3
TiO in 50mL volume is about 1.150, or a percent transmit-
3 2
to a 100mLvolumetric flask. Dilute to about ⁄4 the volume of
tance of 7.
the flask, add 1 mL of 10% hydroxylamine hydrochloride,
5mL of 1,10-phenanthroline, and a predetermined amount of
21. Zirconium Dioxide by Pyrocatechol Violet Method
2 M sodium acetate solution to adjust the pH of the solution to
21.1 Pipet 10 mL(0.2 g) of the sample solution to a 60mL
about3.2.Dilutetovolumeandmix.Whencoloredglassesthat
Squibb separatory funnel, preferably fitted with a TFE-
contain small amounts of NiO, CoO, or CuO are analyzed, use
fluorocarbon stopcock plug. Add 10 mL of HNO , and, if the
10 mL of 1,10-phenanthroline.
solution has warmed significantly, cool to room temperature.
19.2 After 5 min, measure absorbance or percent transmit-
Pipet 10 mL of TOPO-cyclohexane into the solution and
tance using 1cm absorption cells at 508 nm on a suitable
extract zirconium by shaking or mixing for 10 min. Carefully
(spectro)photometer.Thereagentblankisusedasthereference
vent the separatory funnel and then allow the liquid layers to
solution.
separate. Drain off the aqueous layer and discard. Add 10 mL
ofHNO (1 + 1),shakefor2min;allowthelayerstoseparate,
19.3 Calculation—Convert the photometric reading to mil-
drain and reject the acid layer. Drain the TOPO-cyclohexane
ligrams of Fe O by reference to the standard curve, and
2 3
extract into 12mL glass-stoppered centrifuge tubes and cen-
calculate the percent of Fe O as follows:
2 3
trifuge for 3 to 5 min to completely separate from any aqueous
Fe O ,% 5A/ B 310 (7)
~ !
2 3
phase.
where:
21.2 Transfer with a dry pipet 5 mL of the TOPO-
A =Fe O found in sample solution aliquot, mg, and
2 3 cyclohexane extract into a dry 25mLvolumetric flask.Add in
B = amount of sample represented by sample solution
order, while mixing, 10 mL of absolute alcohol, 1 mL of
aliquot, g
0.05% pyrocatechol violet, and 5 mL of pyridine from a dry
pipet. Dilute to volume with absolute alcohol and mix. After
19.4 Preparation of Standard Fe O Curve—To a series of
2 3
30min, measure absorbance or percent transmittance in 1cm
100mLvolumetricflaskscontainingabout50mLofwaterand
or 5cm cells at 655 nm. The reagent blank is the reference
1 mL of HCl (1 + 4), add 0mL, 1mL, 2mL, 3mL, 4mL,
solution.
5mL, and 6mL of standard iron solution, 1mL of 10%
hydroxylamine hydrochloride, 5 mL of 1,10-phenanthroline,
21.3 Calculation—Convert the photometric reading to mi-
and2mLof2 Msodiumacetatesolution.Dilutetovolumeand
crogramsofZrO bymeansofthestandardcurveandcalculate
mix.Measureabsorbanceorpercenttransmittanceasdescribed
the percent of ZrO as follows:
in 19.2. Plot absorbance versus concentration on linear graph
ZrO ,% 5 @A/~B 3 C!#310 (8)
paper or percent transmittance on semi-log paper (percent
transmittance on the log scale, concentration on the linear where:
scale).
A = ZrO found in aliquot of TOPO-cyclohexane extract,
µg,
20. Titanium Dioxide by Tiron Method
B = amount of sample represented by sample solution
aliquot, g, and
20.1 Transferasuitablealiquotnottoexceed0.5g(25mL),
C = fraction of TOPO-cyclohexane extract.
nor containing more than 0.3 mg of TiO,toa50mL
−4
(The equation is multiplied by 10 to convert 1 µg/g of
volumetric flask (if the aliquot taken is less than 25 mL, dilute
sample to percent.)
to 25 mLbefore proceeding).Add in order, with mixing, 2 mL
21.3.1 Example—12 µg of ZrO found in 5 mL of TOPO-
of 20% thioglycolic acid and 5 mL of Tiron reagent solution, 2
cyclohexane extract of a 10mLsample aliquot is calculated as
and adjust the pH to approximately 4.5 by the addition of a
follows:
predetermined quantity of 2 M sodium acetate buffer solution.
4 4
Dilute to volume and mix. Allow the solutions to sit 45 min [12 (0.2 × 0.
...