Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Sodium Bicarbonate (Sodium Hydrogen Carbonate) 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 Sodium Bicarbonate provides, in addition to common physical constants, a general description including typical appearance, applications, 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, Insoluble Matter, Chloride, Phosphate, Sulfur Compounds, Ammonium, Heavy Metals, Iron, Calcium, Magnesium, and Potassium.
NaHCO3
Formula Wt 84.01
CAS No. 144-55-8
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . white solid Applications . . . . . . . . . . . . . . . . . . . . . . . . buffers; pH adjustment Aqueous solubility . . . . . . . . . . . . . . . . . . . . soluble in 10 parts water at 25 °C
SPECIFICATIONS Assay (dried basis). . . . . . . . . . . . . . . . . . . . 99.7–100.3% NaHCO3 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.015% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.003% Phosphate (PO4) . . . . . . . . . . . . . . . . . . . . . 0.001% Sulfur compounds (as SO4). . . . . . . . . . . . . . . 0.003% Ammonium (NH4) . . . . . . . . . . . . . . . . . . . . 5 ppm Heavy metals (by ICP–OES) . . . . . . . . . . . . . . 5 ppm Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.02% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 0.005% Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.005%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4330 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By acid–base titrimetry). Weigh accurately about 3 g, previously dried over indicating-type silica gel desiccant for 24 h, dissolve it in 50 mL of water, add 0.1 mL of methyl orange indicator solution, and titrate with 1 N hydrochloric acid volumetric solution. The sodium bicarbonate content calculated from the total alkalinity, as determined by the titration, should not be less than 99.7% nor more than 100.3% of the weight taken. One milliliter of 1 N hydrochloric acid corresponds to 0.08401 g of NaHCO3.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 10.0 g dissolved in 100 mL of hot water.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 0.33 g, and neutralize with nitric acid.
Phosphate [Part 2: Colorimetry and Turbidimetry; Phosphate; Procedure for Phosphate, Method 1 (Direct Molybdenum Blue)]. Dissolve 2.0 g in 15 mL of dilute hydrochloric acid (1:2), and evaporate to dryness on a hot plate (~100 °C). Dissolve the residue in 25 mL of approximately 0.5 N sulfuric acid, and continue as described.
Sulfur Compounds Dissolve 2.0 g of sample in 20 mL of water, evaporate to 5 mL, add 1 mL of bromine water, and evaporate to dryness. Cool. Dissolve in 10 mL of 10% hydrochloric acid, and evaporate to dryness. Cool. Add 5 mL of 10% hydrochloric acid, and evaporate to dryness. Cool. Dissolve with 10 mL of water, and evaporate to dryness. Cool. Dissolve in 10 mL of water, adjust to approximately pH 2 with 10% hydrochloric acid or dilute ammonium hydroxide (1:3). Filter through a washed filter paper, wash with two 2 mL portions of water, and dilute with water to 30 mL. Add 1 mL of 12% barium chloride reagent solution. For the control, take 0.06 mg of sulfate ion (SO4) in 15 mL of water. Add 1 mL of dilute hydrochloric acid (1:19), dilute with water to 30 mL, and add 1 mL of 12% barium chloride reagent solution. Compare the sample and control solutions after 30 min. Sample solution turbidity should not exceed that of the control solution.
Ammonium Dissolve 2.0 g in 40 mL of ammonia-free water, and add 10 mL of 10% sodium hydroxide reagent solution and 2 mL of Nessler reagent. Any color should notexceed that produced by 0.01 mg of ammonium ion (NH4) in an equal volume of solution containing the quantities of reagents used in the test.
Heavy Metals ([Part 2: Trace and Ultratrace Elemental Analysis; Inductively Coupled Plasma−Optical Emission Spectroscopy (ICP–OES); Calculation of Heavy Metals (by ICP–OES) Results], by ICP–OES). Use 1.0 g sample.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4330 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Dissolve 1.0 g in 30 mL of dilute hydrochloric acid (1:9), dilute with water to 50 mL, and use the solution without further acidification.
Calcium, Magnesium, and Potassium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Magnesium, and Potassium
S a m p l e S t o c k S o l u t i o n . Dissolve 4.0 g of sample with water in a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.04 g).
For the Determination of Calcium, Magnesium, and Potassium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
0.20
0.04; 0.08
N/A
No
Mg
285.2
0.20
0.01; 0.02
A/A
Yes
K
766.5
0.20
0.01; 0.02
A/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4330 ACS Reagent Chemicals, Part 4
