摘要:
使用5,5'-二硫硝基苯甲酸(DTNB)比色法来测定鸡全蛋粉中的金属硫蛋白含量,采用酸水解的方法对样品进行前处理,通过单因素和正交试验确定最优条件为:水解时间24 h,盐酸浓度6 mol/L,质量体积比1:20 g/mL,水解温度130 ℃,在此条件下,水解度为55.28%,金属硫蛋白含量为0.4821 mg/g。在前处理后对检测方法的反应条件及试剂配制条件进行优化,最终选用pH为4.0的磷酸氢二钠-柠檬酸缓冲液配制Ellman试剂,反应最佳pH为7.2。得到的线性回归方程为Y=0.019x+0.027,R2=0.999,呈良好的线性关系。加标回收率在75.83%~88.15%,相对标准偏差为3.10%,该方法具有较好的重现性和准确度和精密度,方法检测限为7.57 μg/g,本方法可以用于样品中金属硫蛋白(MTs)的快速检测。
Abstract:
The experiment used 5, 5'-dithianitrobenzoic acid (DTNB) colorimetric method to quantify metallothioneins (MTs) content, pretreatment of samples by acid hydrolysis. The optimal condition was determined by single factor and orthogonal test:24 hours hydrolysis, 6 mol/L hydrochloric acid, 1:20 mass volume ratio, and hydrolysis temperature at 130℃. The optimized hydrolysis degree could achieve 55.28%, with detection of MTs 0.4821 mg/g. After pretreatment, the reaction conditions and reagent preparation conditions were optimized. Ellman reagent was preparal with disodium hydrogen phosphate-citric acid buffer with pH4.0, the best reaction pH was 7.2. The experiment showed a good linear regression (Y=0.019x+0.027, R2=0.999). Besides, the recovery test result of its standard was 75.83%~88.15%, and the relative standard deviation was 3.10%. The method had relatively good reproducibility, accuracy and precision with detection limit 7.57 μg/g. This method could be used for rapid detection of MTs.
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