The test method for purity in food additives is specified in the Japanese Standards of Food Additives.
Heavy Metals Limit Test is employed in which the heavy metals are darkened with sodium sulfide TS in acidic solution, as their quantity is expressed in terms of the quantity of lead (Pb). The current
component specification is 10 – 20 µg/g, calculated as lead. However, to harmonize with the
international specifications by JECFA, it is predicted that the specifications will become applicable
only to lead and the value will be lowered. By using the twin injection function of ZA3000 series atomic absorption photometers, a large sample volume can be injected and dried without extending the drying time and therefore, lead at 0.2 µg/L level in citric acid can be easily analyzed.
