摘要：Lead and other heavy metals extracted with 4% acetic acid solution at 25° and 80°for 10 minutes from commercial 53 glazed potteries for foodstuff were examined by PbCrO4-, PbSO4-, sulfide- and polarographic method, respectively. The amounts of lead and other heavy metals extracted at 80° were larger than those did at 25°. Lead extracted with 4% acetic acid solution at room temperature for 10 minutes from glazed potteries is measured by PbCrO4- and PbSO4-method in the "Test of Specifications and Standards of Containers", provided by the Ministry of Health and Welfare. It may be practical that the test solution is prepared by extraction with 4% acetic acid solution at 80° for 10 minutes, from a consideration of the case of plastic containers to be extracted with 4% acetic acid solution at 60° for 30 minutes. The amounts of lead extracted at 80° were within 3 ppm in most samples. Consequently, more sensitive method than PbCrO4- and PbSO4- method seems to be required for detection of lead. Lead, copper, zinc, manganese, cadmium, antimony and cobalt were detected in the test solution by polarography. Among them, lead, copper, zinc and manganese were detected in many samples. In the official method, lead is only examined but the method should be attended to other dissolved heavy metals. Furthermore, it is most important that the amounts of extracted heavy metals should be determined per surface area of glazed potteries, because they are not proportional to volumes of the extract but to surface areas.
