A simple and sensitive colorimetric method was developed for determination of cefotaxime sodium(CTX)using gold nano-particles(AuNPs)with 13 nm size as sensor. Specifically,CTX in alkaline medium can be degraded into a sulfhydryl compound u-sing boiling water bath. In hydrochloric acid-sodium citrate buffer(pH=2. 3),the sulfhydryl compound can easily form Au-S with AuNPs and be modified on the surface of AuNPs,leading to the aggregation of AuNPs with color changes from red to blue or purple. Therefore,the concentration of CTX was determined by a UV-Vis spectrometer. The degree of aggregation of AuNPs is expressed as△(A649/A520 ),which is an analytical signal indirectly related to the concentration of CTX. Under the optimal experimental condi-tions,the linear range of CTX was in the range of 0. 020～0. 60 μg·mL-1 and the detection limit was 0. 006 μg·mL-1. The pro-posed method was used to determine CTX in urine,saliva and milk with the recoveries and relative standard deviations(RSD％) ranging from 97. 5～105. 0％and 1. 0～2. 3％,respectively.%本文以13 nm的金纳米颗粒(AuNPs)为探针,构建了一种简单、灵敏的比色法对头孢噻肟钠(CTX)进行检测.其做法是:CTX在碱性介质、沸水浴加热条件下降解生成巯基化合物,该巯基化合物与AuNPs在盐酸-柠檬酸钠缓冲溶液中容易形成Au-S键而修饰在AuNPs的表面,诱导AuNPs的团聚,使AuNPs的颜色从红色变为紫色或蓝色,实现对CTX的检测.CTX浓度在0.020～0.60μg·mL-1范围内与AuNPs的△(A649/A520)呈现良好的线性关系,检出限为0.006μg·mL-1.该方法对尿样、唾液、牛奶中两个浓度水平的CTX加标回收率在97.5～105.0％,相对标准偏差(RSD％)在1.0～2.3％,表明该方法可用于体液与牛奶中CTX的检测.
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