STANDARDS
1. Potassium acid phthalate (If required for standardization of NaOH titrant), Cat. No. P1190, Spectrum.
2. Sodium hydroxymethylsulfonate (HMS) - ~95% purity, Cat. No. 11,270-4, Aldrich.
3. HMS fortification solution (5 μg/μL as SO2):
Weigh approximately 110 mg HMS into small beaker. Dissolve in HMS diluent (C.2.f) and quantitatively transfer to a 10 mL volumetric flask. Dilute to volume with HMS diluent. Calculate equivalent SO2 concentration using the formula:
Conc. SO2, μg/μL = (g HMS weighed x 0.4778) x (%Purity HMS) /1000
[Example: SO2, μg/μL = 110.0 x 0.4778 x 95 /1000 = 4.99 (5.0)]
Note: On the basis of a 50 g sample weight, each 10