ISO 3837:1993
(Main)Liquid petroleum products — Determination of hydrocarbon types — Fluorescent indicator adsorption method
Liquid petroleum products — Determination of hydrocarbon types — Fluorescent indicator adsorption method
The method specified applies to hydrocarbon types over the concentration ranges from 5 % (V/V) to 99 % (V/V) aromatic hydrocarbons, 0,3 % (V/V) to 55 % (V/V) olefins, and 1 % (V/V) to 95 % (V/V) saturated hydrocarbons in petroleum fractions that distill below 315 °C. Restrictions inherent in the method and the determination of precision may limit its application.
Produits pétroliers liquides — Détermination des groupes d'hydrocarbures — Méthode par adsorption en présence d'indicateurs fluorescents
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INTERNATIONAL
STANDARD
First edition
1993-12-15
Liquid Petroleum products -
Determination of hydrocarbon types -
Fluorescent indicator adsorption method
Produits p6 troliers liquides - Determination des groupes
d’h ydrocarbures - Methode par adsorption en pkence d’indicateurs
fluorescen ts
Reference number
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(1 EC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 3837 was prepared by Technical Committee
ISO/TC 28, Petroleum products and lubricants.
Annex A of this International Standard is for information only.
0 ISO 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronie or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1 211 Geneve 20 l Switzerland
Printed in Switzerland
ii
Introduction
The determination of the total volume percent [% (VW)] of saturates,
olefins and aromatics in Petroleum fractions is important in characterizing
the quality of Petroleum fractions as gasoline blending components and
as feeds to catalytic reforming processes, and in characterizing Petroleum
fractions and products from catalytic reforming and from thermal and
catalytic cracking as blending components for motor and aviation fuels.
This information is also important as a measure of the quality of aviation
turbine fuels.
. . .
Ill
This page intentionally left blank
INTERNATIONAL STANDARD
Liquid Petroleum products
- Determination of
- Fluorescent indicator adsorption
hydrocarbon types
method
WARNING - This Standard may involve hazardous materials, operations and equipment. This
Standard does not purport to address all of the safety Problems associated with its use. lt is the
responsibility of the User of this Standard to consult and establish appropriate safety and health
practices and determine the applicability of regulatory limitations Prior to use.
cohol desorbent. Other oxygenated compounds must be
1 Scope
individually verified. When samples containing oxygenated
blending components are analyzed, the hydrocarbon type
results tan be reported on an oxygenate-free basis or, when
This International Standard specifies a fluorescent in-
the oxygenate content is known, the results tan be cor-
dicator adsorption method for the determination of
rected to a total-sample basis.
hydrocarbon types over the concentration ranges
from 5 % (VW) to 99 % (WV) aromatic hydrocarbons,
6 Samples containing dark-coloured components that in-
0,3 % (VW) to 55 % (V/V) olefins, and 1 % (VIV) to
terfere with reading the chromatographic bands cannot be
95 % (V/v) saturated hydrocarbons in Petroleum frac-
analyzed.
tions that distill below 315 “C.
Restrittions inherent in the method and the determi-
nation of precision may limit its application as noted.
2 Normative references
NOTES
The following Standards contain provisions which,
through reference in this text, constitute provisions
1 This method may apply to concentrations outside these
ranges, but the precision has not been determined. of this International Standard. At the time of publi-
cation, the editions indicated were valid. All Standards
2 This test method is intended for use with full boiling
are subject to revision, and Parties to agreements
range products. Cooperative data have established that the
based on this International Standard are encouraged
precision Statement does not apply to Petroleum fractions
to investigate the possibility sf applying the most re-
with narrow boiling ranges near the 315 “C limit. Such
cent editions of the Standards indicated below.
samples are not eluted properly, and results are erratic.
Members of IEC and ISO maintain registers of cur-
rently valid International Standards.
3 The applicability of this test method to products derived
from fossil fuels other than Petroleum, such as coal, shale
or tar Sands, has not been determined and the precision ISO 756-1 :1981, Propan-2-01 for industrial use -
Statement does not apply to such products.
Methods of test - Part 1: General.
4 The precision of this test method has not been deter-
ISO 3171:1988, Petroleum liquids - Automatic pipe-
mined with oxygenated fuels and thus does not apply to
line sampling.
automotive gasolines containing lead anti-knock mixtures.
ASTM D 3663-84, Test method for surface area of
5 The oxygenated blending components methanol,
ca talys ts.
ethanol, methyl tert-butyl ether, tert-amyl methyl ether and
ethyl tefi-butyl ether do not interface with the determi-
ASTM D 4815-89, Test method for analysis of C, to
nation of hydrocarbon types at concentrations normally
C4 alcohols and MTBE in gasoline by gas
found in commercial Petroleum blends. These oxygenated
compounds are not detected since they elute with the al- chromotograph y.
the analyzer outlet. The column tip attached to the
3 Dedinitions
12/2 socket shall have a 2 mm inside diameter. Clamp
the ball and socket together and ensure that the tip
For the purposes of this International Standard, the
does not tend to slide from a Position in a direct line
following definitions apply.
with the analyzer section during the packing and sub-
sequent use of the column.
3.1 saturates: Volume percent [% (VW)] of alkanes
plus cycloalkanes.
For convenience, adsorption columns with Standard
wall tubing, as shown on the left in figure 1, may be
3.2 olefins: Volume percent [% (WV)] of alkenes
used. When using Standard wall tubing for the ana-
plus cycloalkenes plus some alkadienes.
lyzer section, it is necessaty to select tubing of uni-
form bore and to provide a leakproof connection
3.3 aromatics: Volume percent [% (WV)] of con-
between the separator and the analyzer sections.
densed monocyclic and polycyclic aromatic hydro-
Calibrations of Standard wall tubing would be imprac-
carbons plus aromatic olefinic hydrocarbons, some
tical; however, any variations of 0,5 mm or greater,
dienes, compounds containing Sulfur and nitrogen, or
as measured by ordinary calipers, in the outside di-
higher-boiling oxygenated compounds (excluding
ameter along the tube may be taken as an indication
those listed in Note 5).
of irregularities in the inside diameter and such tubing
should not be used. Draw out one end of the tubing
selected for the analyzer section to a fine capillaty to
4 Principle
retain the gel. Connect the other end of the analyzer
section to the separator section with a 30 mm length
Approximately 0,75 ml of Sample is introduced into a
of polyvinyl tubing, making certain that the two glass
special glass adsorption column packed with activated
sections tauch. To ensure a leakproof glass-to-
silica gel. A small layer of the silica gel contains a
mixture of fluorescent dyes. When all the Sample has polyvinyl seal with the analyzer section, it is necessary
been adsorbed onto the gel, alcohol is added to to heat the upper end of the analyzer section until it
desorb the Sample down the column. The hydro- is just hot enough to melt the polyvinyl, then insert
the upper end of the analyzer section into the poly-
carbons are separated, according to their adsorption
affinities, into aromatics, olefins and saturates. The Vinyl sleeve. Alternatively, this seal tan be made by
fluorescent dyes are also separated selectively with securing the polyvinyl sleeve to the analyzer section
by wrapping it tightly with soft wire.
the hydrocarbon types, and render the boundaries of
the aromatic, Olefin and saturate zones visible under
ultraviolet light. The volume percentage [% (VW)] of
52 . Zone-measuring-device.
each hydrocarbon type is calculated from the length
The zones may be marked with glass-writing pencil
of each zone in the column.
and the distances measured with a metre rule, with
NOTE 7 Errors leading to high saturate values and low the analyzer section lying horizontally. Alternatively,
aromatic and low Olefin values tan result if the Sample
the metre rule may be fastened adjacent to the col-
contains C3 or lighter hydrocarbons, or more than 5 % C,
umn. In this case, it is convenient to have each rule
hydrocarbons, or more than 10 % C, and C, hydrocarbons.
fitted with four movable metal index Clips (figure 1) for
Such samples should be depentanized as specified in
marking zone boundaries and measuring the length
ANSI/ASTM DZ001 (see annex A).
of each Zone.
5 Apparatus
5.3 Ultraviolet light Source, with radiation pre-
dominantly at wavelength 365 nm.
5.1 Adsorption columns, either with precision bore
A convenient arrangement consists of one or two
tubing, as shown on the right in figure 1, made of
units 915 mm or 1 220 mm in length mounted verti-
glass and consisting of a charger section with a
cally alongside the apparatus. Adjust to give the best
capillary neck, a separator section, and an analyzer
fluorescence.
section; or with Standard wall tubing, as shown on the
left in figure 1.
5.4 Electric Vibrator, for vibrating the individual col-
The inside diameter of the analyzer section for the
umns or for vibrating the frame supporting multiple
precision bore tubing shall be I,60 mm to I,65 mm
columns.
and an approximately 100 mm thread of mercuty shall
not vary by more than 0,3 mm in any patt of the ana-
5.5 Hypodermic Syringe, of capacity 1 ml, gradu-
lyzer section. In glass-sealing the various sections to
ated to 0,OI ml or 0,02 ml, with needle 102 mm in
each other, long-taper connections shall be made in-
length, with an inside diameter of 0,7 mm to
stead of shouldered connections. Support the silica
I,2 mm.
gel with a small piece of glass wool located between
the ball socket of the 12/2 spherical joint and covering Needles of No. 18, 20 or 22 gauge are satisfactory.
Dimensions in millimetres
unless otherwise indicated
Pressuring gas
Spherical joint S 29
@ int. 12
@ int. 12
w
Pack gel to this Level ‘-1
J
int. 2 Y
Dyed gel
s
Q> int. 5
a Cr1
‘0
-
,-
z ,s
I m
-
d , -
-
.-
-
E
-
-
VI
-
w<
I w
>-
s
Lor ig taper
j @ ext. 3,5
: Q, int. 2
Polyvinyl tubing - t
device (optional)
110 in
1,60 - 1,65
precision bore
capillary tubing
Spherical joint S 13
Standard wall tubing - \ I
-\Tipdrawnout to
fine capillary
Standard column Precision bore column
Figure 1 - Adsorption columns with Standard wall (left) and precision bore (right) tubing in analyzer
section
6.3 Propan=2=ol, 99 % pure, as specified in
6 Reagents
ISO 756-1.
6.4 Pressurizing gas, air (or nitrogen) delivered to
6.1 Silica gel 1) , manufactured to conform to the
the top of the column at pressures controllable over
specifications shown in table 1. The surface area of
the range from 0 kPa gauge to 103 kPa gauge.
the gel is determined in accordance with ASTM D
3663. Determine the pH of the silica gel by placing
5 g of the gel Sample in a 250 ml beaker. Add 7 Sampling
IO0 ml of water and a stirring bar. Standardize the pH
meter with Standards of pH 4 and pH 7. Stir the slurty Obtain a representative Sample in accordance with
with the magnetic stirrer for 20 min and then deter- sampling procedures given in ISO 3171. Store the
mine the pH. Before use, dry the gel in a shallow Sample at 2 “C to 4 “C until ready for analysis.
vessel at 176 “C for 3 h. Transfer the dried gel to an
airtight Container while still hot, and protect it from
atmospheric moisture. 8 Test procedure
NOTE 8 Some batches of silica gel that otherwise meet
8.1 Mount the apparatus assembly in a room or area
specifications have been found to produce Olefin-boundary
darkened to facilitate observations of zone bound-
fading. The exact reason for this phenomenon is unknown
aries. For multiple determinations, assemble an ap-
but will affect accuracy and precision.
paratus that includes the ultraviolet Source, a rack to
hold the columns, and a gas manifold System with
spherical joints to connect to the desired number of
Table 1
- Silica gel specifications
columns.
Surface area: 430 to 530 m*/g
8.2 Freely suspend the column from a loose-fitting
7,0
pt-l of 5 % water slurry: 5,5 to
clamp placed immediately below the spherical joint
Loss on ignition at 955 “C: 4,5 to IO,0 mass %
of the charger section. While vibrating the column
Iron as Fe,O,, dry basis: 50 max. mass ppm
along its entire length, add small increments of silica
gel through a glass funnel into the charger section
Particle size distribution
until the separator section is half full. Stop the Vibrator
and add a 3 mm to 5 mm layer of dyed gel. Start the
Sieve number Mass %
w
Vibrator and vibrate the column while adding additional
silica gel. Continue to add silica gel until the tightly
250 on 60
packed gel extends 75 mm into the charger section.
on 80 100
Wipe the length of the column with a damp cloth
on 100 95 min.
while vibrating the column. This aids in packing the
column by removing static electricity. Vibrate the col-
15 max.
75 through 200
umn for about 4 min after filling is completed.
NOTE 9 More than one column tan be prepared simul-
taneously by mounting several on a frame or rack to which
an electric Vibrator is attached.
6.2 Fluorescent indicator-dyed gel*), a Standard
dyed gel, consisting of a mixture of recrystallized
Attach the filled column to the apparatus assembly in
Petrol red AB4 and purified portions of Olefin and
the darkened room or area. If a permanently mounted
aromatic dyes obtained by chromatographic adsorp-
metre rule is used, fasten
...
INTERNATIONAL
STANDARD
First edition
1993-12-15
Liquid Petroleum products -
Determination of hydrocarbon types -
Fluorescent indicator adsorption method
Produits p6 troliers liquides - Determination des groupes
d’h ydrocarbures - Methode par adsorption en pkence d’indicateurs
fluorescen ts
Reference number
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(1 EC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 3837 was prepared by Technical Committee
ISO/TC 28, Petroleum products and lubricants.
Annex A of this International Standard is for information only.
0 ISO 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronie or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1 211 Geneve 20 l Switzerland
Printed in Switzerland
ii
Introduction
The determination of the total volume percent [% (VW)] of saturates,
olefins and aromatics in Petroleum fractions is important in characterizing
the quality of Petroleum fractions as gasoline blending components and
as feeds to catalytic reforming processes, and in characterizing Petroleum
fractions and products from catalytic reforming and from thermal and
catalytic cracking as blending components for motor and aviation fuels.
This information is also important as a measure of the quality of aviation
turbine fuels.
. . .
Ill
This page intentionally left blank
INTERNATIONAL STANDARD
Liquid Petroleum products
- Determination of
- Fluorescent indicator adsorption
hydrocarbon types
method
WARNING - This Standard may involve hazardous materials, operations and equipment. This
Standard does not purport to address all of the safety Problems associated with its use. lt is the
responsibility of the User of this Standard to consult and establish appropriate safety and health
practices and determine the applicability of regulatory limitations Prior to use.
cohol desorbent. Other oxygenated compounds must be
1 Scope
individually verified. When samples containing oxygenated
blending components are analyzed, the hydrocarbon type
results tan be reported on an oxygenate-free basis or, when
This International Standard specifies a fluorescent in-
the oxygenate content is known, the results tan be cor-
dicator adsorption method for the determination of
rected to a total-sample basis.
hydrocarbon types over the concentration ranges
from 5 % (VW) to 99 % (WV) aromatic hydrocarbons,
6 Samples containing dark-coloured components that in-
0,3 % (VW) to 55 % (V/V) olefins, and 1 % (VIV) to
terfere with reading the chromatographic bands cannot be
95 % (V/v) saturated hydrocarbons in Petroleum frac-
analyzed.
tions that distill below 315 “C.
Restrittions inherent in the method and the determi-
nation of precision may limit its application as noted.
2 Normative references
NOTES
The following Standards contain provisions which,
through reference in this text, constitute provisions
1 This method may apply to concentrations outside these
ranges, but the precision has not been determined. of this International Standard. At the time of publi-
cation, the editions indicated were valid. All Standards
2 This test method is intended for use with full boiling
are subject to revision, and Parties to agreements
range products. Cooperative data have established that the
based on this International Standard are encouraged
precision Statement does not apply to Petroleum fractions
to investigate the possibility sf applying the most re-
with narrow boiling ranges near the 315 “C limit. Such
cent editions of the Standards indicated below.
samples are not eluted properly, and results are erratic.
Members of IEC and ISO maintain registers of cur-
rently valid International Standards.
3 The applicability of this test method to products derived
from fossil fuels other than Petroleum, such as coal, shale
or tar Sands, has not been determined and the precision ISO 756-1 :1981, Propan-2-01 for industrial use -
Statement does not apply to such products.
Methods of test - Part 1: General.
4 The precision of this test method has not been deter-
ISO 3171:1988, Petroleum liquids - Automatic pipe-
mined with oxygenated fuels and thus does not apply to
line sampling.
automotive gasolines containing lead anti-knock mixtures.
ASTM D 3663-84, Test method for surface area of
5 The oxygenated blending components methanol,
ca talys ts.
ethanol, methyl tert-butyl ether, tert-amyl methyl ether and
ethyl tefi-butyl ether do not interface with the determi-
ASTM D 4815-89, Test method for analysis of C, to
nation of hydrocarbon types at concentrations normally
C4 alcohols and MTBE in gasoline by gas
found in commercial Petroleum blends. These oxygenated
compounds are not detected since they elute with the al- chromotograph y.
the analyzer outlet. The column tip attached to the
3 Dedinitions
12/2 socket shall have a 2 mm inside diameter. Clamp
the ball and socket together and ensure that the tip
For the purposes of this International Standard, the
does not tend to slide from a Position in a direct line
following definitions apply.
with the analyzer section during the packing and sub-
sequent use of the column.
3.1 saturates: Volume percent [% (VW)] of alkanes
plus cycloalkanes.
For convenience, adsorption columns with Standard
wall tubing, as shown on the left in figure 1, may be
3.2 olefins: Volume percent [% (WV)] of alkenes
used. When using Standard wall tubing for the ana-
plus cycloalkenes plus some alkadienes.
lyzer section, it is necessaty to select tubing of uni-
form bore and to provide a leakproof connection
3.3 aromatics: Volume percent [% (WV)] of con-
between the separator and the analyzer sections.
densed monocyclic and polycyclic aromatic hydro-
Calibrations of Standard wall tubing would be imprac-
carbons plus aromatic olefinic hydrocarbons, some
tical; however, any variations of 0,5 mm or greater,
dienes, compounds containing Sulfur and nitrogen, or
as measured by ordinary calipers, in the outside di-
higher-boiling oxygenated compounds (excluding
ameter along the tube may be taken as an indication
those listed in Note 5).
of irregularities in the inside diameter and such tubing
should not be used. Draw out one end of the tubing
selected for the analyzer section to a fine capillaty to
4 Principle
retain the gel. Connect the other end of the analyzer
section to the separator section with a 30 mm length
Approximately 0,75 ml of Sample is introduced into a
of polyvinyl tubing, making certain that the two glass
special glass adsorption column packed with activated
sections tauch. To ensure a leakproof glass-to-
silica gel. A small layer of the silica gel contains a
mixture of fluorescent dyes. When all the Sample has polyvinyl seal with the analyzer section, it is necessary
been adsorbed onto the gel, alcohol is added to to heat the upper end of the analyzer section until it
desorb the Sample down the column. The hydro- is just hot enough to melt the polyvinyl, then insert
the upper end of the analyzer section into the poly-
carbons are separated, according to their adsorption
affinities, into aromatics, olefins and saturates. The Vinyl sleeve. Alternatively, this seal tan be made by
fluorescent dyes are also separated selectively with securing the polyvinyl sleeve to the analyzer section
by wrapping it tightly with soft wire.
the hydrocarbon types, and render the boundaries of
the aromatic, Olefin and saturate zones visible under
ultraviolet light. The volume percentage [% (VW)] of
52 . Zone-measuring-device.
each hydrocarbon type is calculated from the length
The zones may be marked with glass-writing pencil
of each zone in the column.
and the distances measured with a metre rule, with
NOTE 7 Errors leading to high saturate values and low the analyzer section lying horizontally. Alternatively,
aromatic and low Olefin values tan result if the Sample
the metre rule may be fastened adjacent to the col-
contains C3 or lighter hydrocarbons, or more than 5 % C,
umn. In this case, it is convenient to have each rule
hydrocarbons, or more than 10 % C, and C, hydrocarbons.
fitted with four movable metal index Clips (figure 1) for
Such samples should be depentanized as specified in
marking zone boundaries and measuring the length
ANSI/ASTM DZ001 (see annex A).
of each Zone.
5 Apparatus
5.3 Ultraviolet light Source, with radiation pre-
dominantly at wavelength 365 nm.
5.1 Adsorption columns, either with precision bore
A convenient arrangement consists of one or two
tubing, as shown on the right in figure 1, made of
units 915 mm or 1 220 mm in length mounted verti-
glass and consisting of a charger section with a
cally alongside the apparatus. Adjust to give the best
capillary neck, a separator section, and an analyzer
fluorescence.
section; or with Standard wall tubing, as shown on the
left in figure 1.
5.4 Electric Vibrator, for vibrating the individual col-
The inside diameter of the analyzer section for the
umns or for vibrating the frame supporting multiple
precision bore tubing shall be I,60 mm to I,65 mm
columns.
and an approximately 100 mm thread of mercuty shall
not vary by more than 0,3 mm in any patt of the ana-
5.5 Hypodermic Syringe, of capacity 1 ml, gradu-
lyzer section. In glass-sealing the various sections to
ated to 0,OI ml or 0,02 ml, with needle 102 mm in
each other, long-taper connections shall be made in-
length, with an inside diameter of 0,7 mm to
stead of shouldered connections. Support the silica
I,2 mm.
gel with a small piece of glass wool located between
the ball socket of the 12/2 spherical joint and covering Needles of No. 18, 20 or 22 gauge are satisfactory.
Dimensions in millimetres
unless otherwise indicated
Pressuring gas
Spherical joint S 29
@ int. 12
@ int. 12
w
Pack gel to this Level ‘-1
J
int. 2 Y
Dyed gel
s
Q> int. 5
a Cr1
‘0
-
,-
z ,s
I m
-
d , -
-
.-
-
E
-
-
VI
-
w<
I w
>-
s
Lor ig taper
j @ ext. 3,5
: Q, int. 2
Polyvinyl tubing - t
device (optional)
110 in
1,60 - 1,65
precision bore
capillary tubing
Spherical joint S 13
Standard wall tubing - \ I
-\Tipdrawnout to
fine capillary
Standard column Precision bore column
Figure 1 - Adsorption columns with Standard wall (left) and precision bore (right) tubing in analyzer
section
6.3 Propan=2=ol, 99 % pure, as specified in
6 Reagents
ISO 756-1.
6.4 Pressurizing gas, air (or nitrogen) delivered to
6.1 Silica gel 1) , manufactured to conform to the
the top of the column at pressures controllable over
specifications shown in table 1. The surface area of
the range from 0 kPa gauge to 103 kPa gauge.
the gel is determined in accordance with ASTM D
3663. Determine the pH of the silica gel by placing
5 g of the gel Sample in a 250 ml beaker. Add 7 Sampling
IO0 ml of water and a stirring bar. Standardize the pH
meter with Standards of pH 4 and pH 7. Stir the slurty Obtain a representative Sample in accordance with
with the magnetic stirrer for 20 min and then deter- sampling procedures given in ISO 3171. Store the
mine the pH. Before use, dry the gel in a shallow Sample at 2 “C to 4 “C until ready for analysis.
vessel at 176 “C for 3 h. Transfer the dried gel to an
airtight Container while still hot, and protect it from
atmospheric moisture. 8 Test procedure
NOTE 8 Some batches of silica gel that otherwise meet
8.1 Mount the apparatus assembly in a room or area
specifications have been found to produce Olefin-boundary
darkened to facilitate observations of zone bound-
fading. The exact reason for this phenomenon is unknown
aries. For multiple determinations, assemble an ap-
but will affect accuracy and precision.
paratus that includes the ultraviolet Source, a rack to
hold the columns, and a gas manifold System with
spherical joints to connect to the desired number of
Table 1
- Silica gel specifications
columns.
Surface area: 430 to 530 m*/g
8.2 Freely suspend the column from a loose-fitting
7,0
pt-l of 5 % water slurry: 5,5 to
clamp placed immediately below the spherical joint
Loss on ignition at 955 “C: 4,5 to IO,0 mass %
of the charger section. While vibrating the column
Iron as Fe,O,, dry basis: 50 max. mass ppm
along its entire length, add small increments of silica
gel through a glass funnel into the charger section
Particle size distribution
until the separator section is half full. Stop the Vibrator
and add a 3 mm to 5 mm layer of dyed gel. Start the
Sieve number Mass %
w
Vibrator and vibrate the column while adding additional
silica gel. Continue to add silica gel until the tightly
250 on 60
packed gel extends 75 mm into the charger section.
on 80 100
Wipe the length of the column with a damp cloth
on 100 95 min.
while vibrating the column. This aids in packing the
column by removing static electricity. Vibrate the col-
15 max.
75 through 200
umn for about 4 min after filling is completed.
NOTE 9 More than one column tan be prepared simul-
taneously by mounting several on a frame or rack to which
an electric Vibrator is attached.
6.2 Fluorescent indicator-dyed gel*), a Standard
dyed gel, consisting of a mixture of recrystallized
Attach the filled column to the apparatus assembly in
Petrol red AB4 and purified portions of Olefin and
the darkened room or area. If a permanently mounted
aromatic dyes obtained by chromatographic adsorp-
metre rule is used, fasten
...
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