FCCV标准-Sodium Metabisulfite焦亚硫酸钠.pdf

FCCV
Monographs Sodium Metabisulfite/423
10 mL of hydrofluoric acid, and heat on a hot plate in a hood Soluble Salt Calculate the percent sodium sulfate from th
until dense, white fumes of perchloric acid evolve
weight of barium sulfate obtained in the Correction for Sodium
C.
aution: Handle perchloric acid in an appropriate
Sulfate Content in the Assay, by the formula
fume hood.
×60.86/W,
Add 10 mL of hydrofluoric acid, and heat again to dense, in which is the weight, in milligrams, of barium sulfate,
white fumes. Quantitatively transfer the solution into a 400- and W is the weight, in milligrams, of the sample taken for
mL beaker, add 200 mL of water, and heat to boiling. Gradu-the Sodium Sulfate determination.
ally add, in small portions an
hile stirring constantly, an
excess of hot b
hloride(about 10 mL), and heat Packaging and Storage Store in well-closed containers.
the mixture on a steam bath for 1 h. Collect the precipitate
on filter, wash
weigh. The w
ride, dry, ignite, and
ms, of the barium sulfate so
icates it
eadiv
equivalent of
on factor by the formula Sodium Metabisulfite
in which is the weight, in milligrams, of the sample taken
Sodium Pyrosulfite
for the Sodium Oxi
termination, and W is the weight, Na2S2O5
Formula 190.11
in milligrams
sample taken for the Sodium Sulfate INS: 223
deterr
caS:17681-57-4
Lead
dution Dissolve 159.8 mg of ACS
reagent-gra
te [Pb(NO3 )2] in 100 mL of water DESCRIPTION
ilute to 1000.0 mL with
zater,an
h
n contains 100
Sodium Metabisulfite occurs as colorless crystals or as a white
this solution in glass
to yellow, crystalline powder. It is freely soluble in water and
conta
slightly soluble in alcohol. Its solutions are acid to litmus.
the day ofuse, dilute, stepwise
ired volume of Lead
Function Preservative; antioxidant.
REQUIREMENTS
25
sample into a 2.
acid, cover with
Identification A 1: 10 aqueous solution gives positive tests
for Sodium and for Sulfite, Appendix IIIA.
Assay Not less than 90.0% and not more than 100.5% of
spOS- Iron Not more than 10 mg/k
Lurry Lead Not more than 2 mg/kg.
Selenium Not more than 5 mg/kg.
room TESTS
Assay Add about 200 mg of sample, accurately weighed,
trument to to exactly 50 mL of 0.1 Niodine contained in a glass-stoppered
flask, and stopper the flask. Allow the solution to stand for
5 min, add mL of hydrochloric acid, and titrate the excess
iodine with 0. N sodium thiosullate, adding starch TS as the
indicator. Each milliliter of 0. Niodine is equivalent to 4.752
n that ob-mg of.
Iron Add 2 of hydrochloric acid to 500 mg of sample
e
and evaporate to dryness on a steam bath. Dissolve the residue
roomot brboudrehlor dandthe ate r, ad tee
Loss on Ignition T
solution to remove the
dried at105o
ed, into a suitable bromine. Cool, dilute with water to 25 mL, then add 50 mg
tared crucible, and ignite at 900 to constant weight.
of ammonium persulfate and 5 mL of ammonium thiocyanate
pH(20% slurry) Determine as directed under pH Determi-
TS. Any red or pink color does not exceed that produced in
n