ASTM E147-61(2022)

Standard Specification for Apparatus for Microdetermination of Nitrogen by Kjeldahl Method

ABSTRACT
This specification covers the design and dimensional requirements for the digestion and distillation apparatus used for the microdetermination of nitrogen by the Kjeldahl method, and modifications thereof at atmospheric pressure. This apparatus is comprised primarily of digestion flasks, micro Kjeldahl digestion rack, one-piece model distillation apparatus, and Pregl (Parnas-Wagner) type distillation apparatus.
SCOPE
1.1 This specification covers digestion and distillation apparatus used for the microdetermination of nitrogen by the Kjeldahl method, and modifications thereof at atmospheric pressure.  
Note 1: This specification is based on those originally developed by the Committee on Microchemical Apparatus, Division of Analytical Chemistry, American Chemical Society.2  
1.2 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: 31-Aug-2022
• ICS: 71.040.20 - Laboratory ware and related apparatus
• Technical Committee: E41 - Laboratory Apparatus
• Drafting Committee: E41.01 - Laboratory Ware and Supplies

Relations

• Refers: ASTM E124-94(2010) - Standard Specification for Weighing and Drying Apparatus for Microchemical Analysis
• Effective Date: 01-Jul-2010
• Refers: ASTM E124-94(2005) - Standard Specification for Weighing and Drying Apparatus for Microchemical Analysis
• Effective Date: 01-May-2005
• Refers: ASTM E124-94(1999) - Standard Specification for Weighing and Drying Apparatus for Microchemical Analysis
• Effective Date: 10-May-1999

Overview

ASTM E147-61(2022) - Standard Specification for Apparatus for Microdetermination of Nitrogen by Kjeldahl Method provides comprehensive requirements for laboratory apparatus used in precise nitrogen analysis. This specification addresses the design and dimensional characteristics needed to ensure reliable microdetermination of nitrogen via the renowned Kjeldahl method, conducted at atmospheric pressure.

The standard applies specifically to:

• Digestion and distillation apparatus for small sample sizes
• Digestion flasks, micro Kjeldahl digestion racks, distillation devices, and components of Pregl (Parnas-Wagner) type apparatus

The guidance is essential for laboratories following internationally accepted procedures for nitrogen analysis in a variety of materials, particularly when sample volume is limited.

Key Topics

• Apparatus Specifications

  • Details precise requirements for digestion flasks, including shock-resistant glass and dimensional tolerances
  • Covers micro Kjeldahl digestion racks featuring gas or electric heaters, flask supports, and fume ducts to ensure safety and effective fume removal
  • Includes specifications for one-piece model distillation apparatus and Pregl (Parnas-Wagner) type setups

• Dimensional Tolerances

  • Specifies permissible length tolerances for apparatus components, ensuring consistency and interchangeability

• Sample Introduction Methods

  • Recommendations for weighing tubes, combustion boats, and introductory techniques to prevent sample loss or spattering

• Operational Safety and Efficiency

  • Mandates structural features that protect users from excessive heat and fumes
  • Describes heat regulators and fume extraction solutions for safe laboratory workflows

Applications

ASTM E147-61(2022) is widely used in analytical laboratories involved in food, environmental, agricultural, and biochemical research. Applications include:

• Micro-scale Nitrogen Analysis

  • Determination of protein content in foodstuffs and agricultural products via the Kjeldahl method
  • Analysis of nitrogen-containing compounds in chemicals and biological samples

• Quality Control and Compliance

  • Ensures precise apparatus setup for regulatory testing and industrial quality control
  • Supports adherence to international best practices for laboratory instrumentation

• Educational and Research Laboratories

  • Provides standardized setup guidance for teaching the Kjeldahl nitrogen determination technique
  • Ensures reproducibility and comparability of experimental results across institutions

Related Standards

For enhanced compatibility and comprehensive laboratory setup, consider these relevant ASTM standards:

• ASTM E124 - Specification for Weighing and Drying Apparatus for Microchemical Analysis
• International best practices from the World Trade Organization Technical Barriers to Trade (TBT) Committee

Laboratories may also reference other regional or international standards on microchemical apparatus and routine analysis methods to supplement their compliance and laboratory quality assurance programs.

Practical Value

Implementing ASTM E147-61(2022) guarantees that laboratory equipment for nitrogen analysis is accurately manufactured and safely used. This supports reliable results, increased sample throughput, and alignment with globally recognized quality systems. Adhering to this standard enables laboratories to maintain high analytical performance across a broad range of nitrogen determination applications utilizing the classic Kjeldahl method.

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:E147 −61 (Reapproved 2022)
Standard Specification for
Apparatus for Microdetermination of Nitrogen by Kjeldahl
Method
This standard is issued under the fixed designation E147; 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.
1. Scope 3. The flasks shall be made of shock-resistant glass with linear
−7
coefficient of expansion not greater than 33.5×10 cm/cm
1.1 This specification covers digestion and distillation ap-
·°C.
paratus used for the microdetermination of nitrogen by the
Kjeldahl method, and modifications thereof at atmospheric
NOTE 2—The weighing tubes described in Specification E124 Figs.
pressure. 12–14 are recommended for introducing solid samples into the micro
Kjeldahl digestion flasks. Combustion boats, Fig. 1 and Fig. 2 of
NOTE 1—This specification is based on those originally developed by
Specification E124, are recommended for use with waxy and nonvolatile
the Committee on Microchemical Apparatus, Division of Analytical
liquid samples.
Chemistry, American Chemical Society.
1.2 This international standard was developed in accor-
5. Digestion Rack
dance with internationally recognized principles on standard-
5.1 The micro Kjeldahl digestion rack shall be portable and
ization established in the Decision on Principles for the
shall consist of flask heaters (either gas or electric), a flask
Development of International Standards, Guides and Recom-
support,andafumeduct.Therackshallbesuppliedwithaheat
mendations issued by the World Trade Organization Technical
deflector mounted under the burners to prevent overheating of
Barriers to Trade (TBT) Committee.
the bench top.
2. Referenced Documents 5.1.1 Heaters—The source of heat may be either electric or
3 gas. In operation, each heater shall supply sufficient heat to a
2.1 ASTM Standards:
30-mL flask to cause 15 mL of water at 25°C to come to a
E124Specification for Weighing and Drying Apparatus for
rollingboilinnotlessthan2ormorethan3min.Adeviceshall
Microchemical Analysis
be provided for regulating the amount of heat supplied to the
flask so that these conditions can be met. The amount of heat
3. Tolerances
supplied to the flasks also shall be so adjustable that low-
3.1 The following commercial length tolerance shall be
temperature digestions are possible. Switches and controls
adhered to, unless otherwise specified:
shall be conveniently located and shall remain cool enough to
Up to 10 mm ±1 mm
handle even after long periods of operation.
10 to 100 mm ±2 mm
100 to 200 mm ±3 mm
NOTE 3—Boiling chips shall be added when testing the heaters to
200 mm ±4 mm
minimize superheating, and the burners and rack shall be at equilibrium
temperature.
4. Digestion Flasks
5.1.2 Flask Support—The support on which the bulbs of the
4.1 Digestion flasks of three types shall conform to the
flasks rest shall shield the necks of the flasks from excessive
requirements prescribed in Table 1 and Fig. 1, Fig. 2, and Fig.
heating during digestion and shall be provided with circular
openingsnotexceeding26mmindiameter,centeredovereach
This specification is under the jurisdiction of ASTM Committee E41 on
heater.
Laboratory Apparatus and is the direct responsibility of Subcommittee
5.1.3 Fume Duct—The fume duct shall provide means for
E41.01Laboratory Ware and Supplies.
Current edition approved Sept. 1, 2022. Published September 2022. Originally
adequately removing the fumes evolved during the digestion
approvedin1959.Lastpreviouseditionapprovedin2017asE147–61(2017).DOI:
andshallsupportthenecksoftheflasksatananglegreaterthan
10.1520/E0147-61R22.
35° to the horizontal. Fume ducts meeting these specifications
Committee on Microchemical Apparatus, “Recommended Specification for
areshowninFig.4andFig.5.ThefumeductillustratedinFig.
MicrochemicalApparatus, Micro Kjeldahl Nitrogen,” Analytical Chemistry,Vol 23,
1951, p. 523.
4 is supported and held in place by suitable clamps mounted at
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
either end of the digestion rack. The fume duct in Fig. 5 rests
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
upon a circular support plate and is held in place by springs
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. from the plate to the four glass hooks. The concave center
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