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酱油中成份较复杂.特别是氯化物含量高.影响铅的测定.为了消除氯化物等其它物质的干扰,我们利用氢氧化镁共沉淀法进行前处理.方法的回收率90%～98%,精密度R·S=2.7%.1 实验部分1.1 仪器WFX—IC型原子吸收分光光度计;铅空心阴极灯;离心机.1.2 仪器条件 狭缝0.2nm,灯电流2mA,能量75%,空气乙炔焰为贫化性火焰.1.3 试剂 铅标准溶液(1mg/ml);200g/LNaoH溶液;200g/LMgCl_2溶液;硝酸(分析纯).1.4 标准曲线绘制 吸取0.0,5.0,10.0,15.0,20.0,25.0μg铅标准溶液于10ml比色管中,与样品相同条件测得标准曲线:Y=0.3765X+5.4×10~(-4),r=0.999.
Soy sauce is more complex ingredients, especially high chloride content affect the determination of lead.In order to eliminate the interference of chloride and other substances, we use magnesium hydroxide coprecipitation method for pretreatment recovery of 90% to 98% Precision R · S = 2.7% .1 Experimental 1.1 Instrument WFX-IC atomic absorption spectrophotometer; Lead hollow cathode lamp; Centrifuge .1.2 Instrument conditions Slit 0.2nm, lamp current 2mA, energy 75%, air Acetylene Flame for the degenerative flame .1.3 reagent lead standard solution (1mg / ml); 200g / LNaoH solution; 200g / LMgCl2 solution; nitric acid (analytical grade) .1.4 standard curve drawing draw 0.0,5.0,10.0,15.0,20.0,25.0 μg standard solution of lead in 10ml colorimetric tube, the standard curve measured with the same sample: Y = 0.3765X + 5.4 × 10 -4, r = 0.999.