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对食品中苯甲酸的测定方法,国标法中介绍的是簿层层析法,操作比较繁杂,且又属於半定量法;气相色谱法虽然可以测定苯甲酸,但需具备色谱仪且费时。用紫外分光光度法则可克服上述不足。现介绍如下。1 材料与方法1.1 仪器751紫外分光光度计,氢弧灯,石英比色皿,光径1.0cm,125ml分液漏斗,50ml具塞比色管。1.2 试剂无水乙醚,6NHCl,4%NaCl溶液,1%NaHCO_3溶液,苯甲酸标准溶液,(同GB5009.29.85配制方法)。1.3 操作步骤称取2.5g事先混匀的样品置於
Determination of benzoic acid in food, GB method described in the book chromatography, the operation is more complicated, and belongs to the semi-quantitative method; although the determination of benzoic acid by gas chromatography, but need to have a chromatograph and time-consuming. UV spectrophotometry can overcome these deficiencies. Now introduced as follows. 1 Materials and Methods 1.1 Instruments 751 UV spectrophotometer, hydrogen arc lamp, quartz cuvette, light diameter 1.0cm, 125ml separatory funnel, 50ml plugged with colorimetric tube. 1.2 Reagents Anhydrous ether, 6NHCl, 4% NaCl solution, 1% NaHCO_3 solution, benzoic acid standard solution (with GB5009.29.85 preparation method). 1.3 operation steps Weigh 2.5g pre-mixed samples placed