Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Phosphoric Acid, Ultratrace Part 4, Monographs for Reagent Chemicals: General Descriptions, Specifications, and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents
ABSTRACT This monograph for Phosphoric Acid, Ultratrace provides, in addition to common physical constants, a general description including typical appearance, applications, aqueous solubility, density, and pKa. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Chloride, Nitrate, Sulfate, Mercury, and Trace Metals.
H3PO4
Formula Wt 98.00
CAS No. 7664-38-2
Suitable for use in ultratrace elemental analysis. Note: This reagent must be packaged in a preleached Teflon bottle and used in a clean laboratory environment to maintain purity.
GENERAL DESCRIPTION Typical appearance Applications . . . . . Aqueous solubility . Density . . . . . . . . pKa . . . . . . . . . .
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clear, viscous liquid trace metal analysis miscible 1.68 2.1
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥85.0% H3PO4 Maximum Allowable Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 3 ppm Nitrate (NO3) . . . . . . . . . . . . . . . . . . . . . . . 5 ppm Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.003% Mercury (Hg) . . . . . . . . . . . . . . . . . . . . . . . 5 ppb Aluminum (Al) . . . . . . . . . . . . . . . . . . . . . . 50 ppb
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4269 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Barium (Ba) . . . . Boron (B) . . . . . Cadmium (Cd) . . Calcium (Ca) . . . Chromium (Cr) . . Cobalt (Co) . . . . Copper (Cu) . . . . Iron (Fe) . . . . . . Lead (Pb) . . . . . Lithium (Li) . . . . Magnesium (Mg) . Manganese (Mn) . Molybdenum (Mo) Potassium (K) . . . Sodium (Na) . . . . Strontium (Sr) . . Tin (Sn). . . . . . . Titanium (Ti) . . . Vanadium (V) . . . Zinc (Zn) . . . . . . Zirconium (Zr) . .
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5 ppb 5 ppb 5 ppb 50 ppb 5 ppb 10 ppb 5 ppb 20 ppb 10 ppb 5 ppb 10 ppb 5 ppb 5 ppb 5 ppb 50 ppb 5 ppb 10 ppb 5 ppb 5 ppb 50 ppb 5 ppb
TESTS Assay (By acid–base titrimetry). Weigh accurately about 2.0 g, and dilute with 120 mL of water. Titrate potentiometrically with 1 N sodium hydroxide volumetric solution to the inflection point at a pH near 9, using the first derivative method [Part 2: Titrimetric Methods; Potentiometric Titrations; First Derivative Method for Determination of Equivalence Point]. One milliliter of 1 N sodium hydroxide corresponds to 0.04900 g of H3PO4.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Dilute 3.0 g of sample with water to 25 mL, and add 0.5 mL of nitric acid.
Nitrate [Part 2: Colorimetry and Turbidimetry; Nitrate; Procedure for Nitrate, Method 1 (Brucine Sulfate)]. For sample solution A, use 2.0 g in 4 mL of water. For control solution B, use 1.0 g and 1 mL of nitrate ion (NO3) standard solution.
Sulfate Use test as for phosphoric acid, [Part 4: Phosphoric Acid].
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4269 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Mercury (By CVAAS, [Part 2: Trace and Ultratrace Elemental Analysis; Mercury Determination by CVAAS]). To each of three 100 mL volumetric flasks containing about 35 mL of water, add 4.0 g of sample. To the second and third flasks, add mercury ion (Hg) standards of 10 ng (2.5 ppb) and 20 ng (5.0 ppb), respectively. Add 5 mL of nitric acid to all three flasks, and dilute to the mark with water. Mix. Zero the instrument with the blank, and determine the mercury content using a suitable mercury analyzer system (1.0 mL of 0.01µg/mL Hg = 10 ng).
Trace Metals Determine the aluminum, barium, boron, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, molybdenum, potassium, sodium, strontium, tin, titanium, vanadium, zinc, and zirconium by the ICP–OES method described in [Part 2: Trace and Ultratrace Elemental Analysis; Inductively Coupled Plasma−Optical Emission Spectroscopy (ICP–OES); Preconcentration of Ultratrace-Grade Reagents for Analysis by ICP–OES].
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4269 ACS Reagent Chemicals, Part 4
