Page 137 - Analytical method for food addtives

Reference
12,13
collected in electrolyte-trapping solution and then detected by
assemble (as 8,9). SO 2 purged with N 2 from acidified sample,
in gas diffusion cell into flowing stream of malachite green,
to produce SO 2 gas which diffuses across Teflon membrane
Test solution reacted with NaOH, then test stream acidified
which is discoloured. Detector set at 615 nm
differential pulse polarography
Method conditions
solution to test portion, blend until
Solid foods: Add 3–30 times TCM
g samples add 100 mL 5 % 2–5 Reflux with HCl in distillation apparatus. Sweep SO 2 through a condenser with nitrogen into hydrogen peroxide ethanol:water mixture solution. SO 2 oxidised to sulphuric acid which is titrated with standardised NaOH solution 6,7 Sulphite oxidised to sulphate in the presence of sulphite Liq
White wine: Add 19 times TCM
homogeneous and centrifuge
Sample preparation
Summary of methods for sulphites in foods Matrix To 50 Foods . Foods 10 Foods alcohol to 100 necessary Foods and beverages solution to 1–2

Table 8.1 (a) Method Optimised Monier–Williams Enzymatic Differential pulse polarographic FIA