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目的建立流动注射法检测植物油中醛类化合物的方法。方法利用醛类物质和间苯三酚在酸催化作用下生成红色单甲川类衍生物的原理,在自制的流动注射分析仪中,以相同摩尔量的甲醛、乙醛、正丙醛、正丁醛、正戊醛、正己醛、正庚醛、正辛醛和正壬醛配成的混合醛为标准物质,通过优化反应中的酸催化剂种类及用量、温度、试剂浓度以及流速等参数,确定最佳的流动注射法检测植物油中的醛类物质方法。结果最佳的流动注射条件为:两个蠕动泵的流速控制在0.5 m L/min,检测波长为455 nm,进样量为100μL,恒温水浴槽的温度为75℃。在该条件下,醛类化合物在0.0006~0.03 mol/L浓度范围内具有良好的线性关系,线性方程为Y=3.19×10~8X+1.12×10~5,r~2=0.998;该方法的相对标准偏差为0.41%~2.1%,回收率在90%以上。结论该方法可用于实际食用油样品中醛类物质的检测,具有方法简单、测试快速、数据准确的特点,可在食品检测领域中获得推广。
Objective To establish a method for the determination of aldehydes in vegetable oil by flow injection. Methods The principle of using aldehydes and phloroglucinol to produce red monomethine derivatives under acid catalysis was studied. In a homemade flow injection analyzer, the same molar amount of formaldehyde, acetaldehyde, n-propionaldehyde, n-butyl Aldehydes, n-valeraldehyde, n-hexanal, n-heptanal, n-octanal and n-nonyl aldehyde as the standard material, by optimizing the type and amount of acid catalyst, temperature, reagent concentration and flow rate and other parameters to determine the most Good flow injection method for the determination of aldehydes in vegetable oils. Results The best flow injection conditions were as follows: the flow rate of the two peristaltic pumps was controlled at 0.5 m L / min, the detection wavelength was 455 nm, the injection volume was 100 μL and the temperature of the thermostatic water bath was 75 ℃. Under these conditions, the aldehydes showed a good linearity in the range of 0.0006 ~ 0.03 mol / L with the linear equation Y = 3.19 × 10 ~ 8X + 1.12 × 10 ~ 5 and r ~ 2 = 0.998. The relative standard deviation was 0.41% ~ 2.1%, the recovery rate was above 90%. Conclusion The method can be used for the detection of aldehydes in real cooking oil samples. The method has the advantages of simple method, rapid testing and accurate data. It can be popularized in the field of food testing.