This standard specifies the general method of aluminum colorimetric determination with ammonium aurin tricarboxylate (aluminum reagent) and chrome azurol S. Detection range of ammonium aurin tricarboxylate (aluminum reagent) spectrophotometry is 0.4μg/mL~2μg/mL (calculated in Al); detection range of visual colorimetry is 0.2μg/mL~2μg/mL (calculated in Al). Detection range of chrome azurol S spectrophotometry is 0.01μg~0.2μg/mL (calculated in Al) and detection range of visual colorimetry is 0.008μg/mL~0.2μg/mL (calculated in Al).
2 Normative References
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to (excluding corrections), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of these documents is applicable. For undated references, the latest edition of the normative document is applicable to this standard.
GB/T 602 "Chemical Reagent-Preparations of Stock Standard Solutions" (GB/T 602-2002, ISO 6353-1:1982, NEQ)
GB/T 603 "Chemical Reagent-Preparations of Reagent Solutions for Use in Test Methods" (GB/T 603-2002, ISO 6353-1:1982, NEQ)
GB/T 6682 "Water for Laboratory Use; Specifications" (GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 9721 "Chemical Reagent-General Rules for the Molecular Absorption Spectrophotometry"
3 Method Principle
3.1 Ammonium aurin tricarboxylate (aluminum reagent) colorimetric method
Slight soluble red chelate produced by aluminum and ammonium aurin tricarboxylate in acetic acid medium of 4~5 pH value may be used for the determination of aluminum by spectrophotometry or visual colorimetry. Adding protective colloid may make solution color stable.
3.2 Colorimetric method with chrome azurol S
Blue complex produced by aluminum and chrome azurol S and hexadecyl trimethyl ammonium bromide in faintly acid medium around 6 pH value may be used for determination of aluminum by spectrophotometry or visual colorimetry.
4 Reagents and Materials
Standard solution, preparation and product being used in this standard shall be prepared in accordance with the requirements of GB/T 602 and GB/T 603; water for experiment use shall meet the specification for level 3 water in GB/T 6682.
