Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Ammonium Phosphate, Monobasic (Ammonium Dihydrogen Phosphate) 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
ACS Reagent Chemicals Downloaded from pubs.acs.org by EAST CAROLINA UNIV on 01/03/19. For personal use only.
A u t h o r i t a t i v e V e r s i o n : This version is current as of 01 Jun 2016.
ABSTRACT This monograph for Ammonium Phosphate, Monobasic provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, pH of a 5% Solution at 25.0 °C, Insoluble Matter, Chloride, Nitrate, Sulfate, Heavy Metals, Iron, Calcium, Magnesium, Potassium, and Sodium.
NH4+
NH4H2PO4
-O
O P OH OH
Formula Wt 115.03
CAS No. 7722-76-1
SUPPLEMENTS & UPDATES Published
Authoritative
28 Feb 2017
01 Jun 2016
Expired
Type
Summary
Other Versions
Original
First on-line publication, based on 11th ed.
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
© 2017 American Chemical Society
colorless solid buffer solutions melting point, 190 °C 1 g in 2.5 mL at 25 °C
A
DOI:10.1021/acsreagents.4033.20160601 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥98.0% NH4H2PO4 pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 3.8–4.4
Insoluble matter . . . Chloride (Cl) . . . . . Nitrate (NO3) . . . . . Sulfate (SO4) . . . . . Heavy metals (as Pb) Iron (Fe) . . . . . . . . Calcium (Ca) . . . . . Magnesium (Mg) . . . Potassium (K) . . . . . Sodium (Na) . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
Maximum Allowable 0.005% 5 ppm 0.001% 0.01% 5 ppm 0.001% 0.001% 0.0005% 0.005% 0.005%
TESTS Assay (By acid–base titration). Weigh accurately about 2 g, and dissolve in 50 mL of water. Titrate with 1 N sodium hydroxide to the inflection point occurring at about pH 8, as measured with a pH meter. One milliliter of 1 N sodium hydroxide corresponds to 0.1150 g of NH4H2PO4.
%NH4H2PO4 =
mL × N NaOH × 11.50 Sample wt (g)
pH of a 5% Solution at 25.0 °C [Part 2: Direct Electrometric Methods; pH Potentiometry; pH Range; Procedure for pH of a 5% Solution at 25.0 °C].
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20.0 g dissolved in 200 mL of water.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 2.0 g of sample and 3 mL of nitric acid.
Nitrate [Part 2: Colorimetry and Turbidimetry; Nitrate; Procedure for Nitrate, Method 1 (Brucine Sulfate)]. For sample solution A, use 1.5 g. For control solution B, use 1.5 g and 1.5 mL of nitrate ion (NO3) standard solution.
Sulfate Dissolve 1.0 g in 15 mL of water, and add 2.5 mL of 10% hydrochloric acid (solution approximately pH 2). Filter through a washed filter paper, and add 10 mL of water through the same filter paper. For the control, add 0.10 mg of sulfate ion (SO4)
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4033.20160601 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
in 20 mL of water, and add 1.0 mL of (1:19) hydrochloric acid. Dilute both to 35 mL with water, add 5.0 mL of 40% barium chloride reagent solution, and mix. Observe turbidity after 10 min. Sample solution turbidity should not exceed that of the control solution.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dissolve 6.0 g in 30 mL of water. Use 25 mL to prepare the sample solution, and use the remaining 5 mL to prepare the control solution.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 2 (Hydroxylamine and 1,10-Phenanthroline)]. Use 1.0 g. Add 3 mL of dilute ammonium hydroxide (1:4) to both the sample and the standard solutions.
Calcium, Magnesium, Potassium, and Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Magnesium, Potassium, and Sodium
S a m p l e S t o c k S o l u t i o n . Dissolve 20.0 g of sample in 75 mL of water, add 2 mL of nitric acid (1:1), transfer to a 100 mL volumetric flask, and mix (1 mL = 0.20 g).
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
4.0
0.02; 0.04
N/A
No
Mg
285.2
4.0
0.01; 0.02
A/A
Yes
K
766.5
1.0
0.05; 0.10
A/A
No
Na
589.0
0.10
0.005; 0.01
A/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
C
DOI:10.1021/acsreagents.4033.20160601 ACS Reagent Chemicals, Part 4
