Foreword

This standard replaces the method for determination of lead in GB 5009.12-2010 “National food safety standard Determination of lead in foods”, GB/T 20380.3-2006 “Starch and derived products-Heavy metals content-Part 3: Determination of lead content by atomic absorption spectrometry with electrothermal atomization, GB/T 23870-2009 “Determination of Pb in propolis-Microwave digestion-Graphite furnace atomic absorption spectrophotometry”, GB/T 18932.12-2002 “Method for the determination of potassium, sodium, calcium, magnesium, zinc, iron, copper, manganese, chromium, lead, cadmium contents in honey-Atomic absorption spectrometry”, NY/T 1100-2006 “Determination of lead, cadmium in rice-Graphite furnace atomic absorption spectrometry”, and SN/T 2211-2008 “Determination of lead, cadmium in royal jelly-Graphite furnace atomic absorption spectrometry method”.

Compared with GB 5009.12-2010, the main changes of this standard are as follows:

——in the pretreatment method, the wet digestion and digestion by pressure digestion tank have been retained, the dry ashing and ammonium persulfate ashing method have been deleted and the microwave digestion has been added;

——the graphite furnace atomic absorption spectrometry method has been retained as the method I, using ammonium dihydrogen phosphate-palladium nitrate solution as the matrix modifier; the flame atomic absorption spectrometry has been retained as the method III; and the dithizone colorimetry has been retained as the method IV;

——the inductively coupled plasma mass spectrometry has been added as the method II;

——the hydride generation atomic fluorescence spectrometry and single sweep polarography have been deleted;

——the Annexes for temperature programming for microwave digestion, and instrument reference conditions for graphite furnace atomic absorption spectrometry and flame atomic absorption spectrometry have been added.