Suitable for use in ultratrace elemental analysis.
Note: Reagent must be packaged in a preleached Teflon bottle and used
in a clean laboratory environment to maintain purity.
GENERAL DESCRIPTION
Typical appearance: clear liquid with a sharp odor
Analytical use: trace metal analysis
Change in state (approximate): boiling point, 118 °C; freezing point, 16
°C
Aqueous solubility: miscible with water
pKa: 4.8
SPECIFICATIONS
Assay
≥90% CH3COOH
Maximum Allowable
Chloride (Cl)
1 ppm
Sulfate (SO4)
1 ppm
Mercury (Hg)
1 ppb
Aluminum (Al)
1 ppb
Barium (Ba)
1 ppb
Boron (B)
5 ppb
Cadmium (Cd)
1 ppb
Calcium (Ca)
1 ppb
Chromium (Cr)
1 ppb
Cobalt (Co)
1 ppb
Copper (Cu)
1 ppb
Iron (Fe)
5 ppb
Lead (Pb)
1 ppb
Lithium (Li)
1 ppb
Magnesium (Mg)
1 ppb
Manganese (Mn)
1 ppb
Molybdenum (Mo)
1 ppb
Potassium (K)
1 ppb
Silicon (Si)
5 ppb
Sodium (Na)
5 ppb
Strontium (Sr)
1 ppb
Tin (Sn)
1 ppb
Titanium (Ti)
1 ppb
Vanadium (V)
1 ppb
Zinc (Zn)
1 ppb
Zirconium (Zr)
1 ppb
TESTS
Assay. (By acid–base titrimetry). The
assay of acetic acid used for ultratrace metal analysis may vary, depending
on the method of purification. Tare a glass-stoppered flask containing about
30 mL of water. Quickly add about 3 mL of the sample, stopper, and weigh accurately.
Dilute to about 50 mL, add 0.15 mL of methyl orange indicator solution, and
titrate with 1 N sodium hydroxide. One milliliter of 1 N sodium hydroxide corresponds
to 0.06005 g of acetic acid.
% Acetic acid =
(mL × N NaOH) × 6.005
Sample wt (g)
Chloride. (Page 35). Dissolve 10.0 g
in 10 mL of water.
Sulfate. To 48 mL (50 g) of sample, add
2 mL of 1% sodium carbonate solution, and evaporate to dryness on a hot plate
(≈100 °C). Dissolve the residue in 1.0 mL of 10% hydrochloric acid and 15
mL of water. Dilute to 25 mL with water. For the control, take 0.05 mg of sulfate
ion (SO4) in 20 mL of water, add 1.0 mL
of 10% hydrochloric acid, and dilute to 25 mL. To sample and control solutions,
add 1 mL of 12% barium chloride solution. Compare after 10 min. Sample turbidity
should not exceed that of the control solution.
Mercury. (By CVAAS, page 65). To a set
of three 100-mL volumetric flasks containing about 35 mL of water, add 20.0
g of sample. To the second and third flasks, add mercury ion (Hg) standards
of 10 ng (0.5 ppb) and 20 ng (1.0 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 0.01 µg/mL Hg = 10 ng).
Trace Metals. Determine the aluminum,
barium, boron, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium,
magnesium, manganese, molybdenum, potassium, silicon, sodium, strontium, tin,
titanium, vanadium, zinc, and zirconium by the ICP–OES method described on page
69.
