质子化壳聚糖功能性金纳米搅拌棒吸附萃取-离子色谱法测定乳制品中的亚硝酸盐及硝酸盐

Determination of Nitrite and Nitrate in Dairy Products by Protonated Chitosan Functionalized Gold Nanoarticles Coated Stir Bar Sorptive Extraction with Ion Chromatography

以刻蚀不锈钢丝为基体,采用化学沉积法在其表面制备金纳米粒子(AuNPs),再利用自组装技术将壳聚糖(CTS)修饰于AuNPs上,并对其进行质子化改性,制备了一种以质子化壳聚糖功能化AuNPs为涂层的固相萃取搅拌棒(PCTS/AuNPs-SBSE),结合离子色谱法(IC),建立了乳制品中亚硝酸盐和硝酸盐的测定方法。优化了萃取温度、溶液pH值、萃取时间以及解析溶剂和时间。PCTS/AuNPs-SBSE-IC法测定亚硝酸盐和硝酸盐的线性范围分别为0.005~0.5 mg/L和0.02~5.0 mg/L,相关系数为0.9985和0.9988,检出限为1.2μg/L和6.7μg/L(S/N=3),富集倍数为22~25倍,RSD为2.6%~7.2%(n=5)。在实际样品分析中,加标回收率为84.7%~100.4%,RSDs在2.8%~8.5%(n=3)之间。结果表明,本方法简单、灵敏、选择性好,可用于乳制品中硝酸盐和亚硝酸盐的富集检测。

Protonated chitosan(PCTS)modified gold nanoparticles(AuNPs)composites coating was fabricated using an etched stainless steel wire as a support on which AuNPs were first deposited,then after modified with CTS by self-assembly method and protonated.A method of stir bar sorptive extraction(SBSE)based on PCTS/AuNPs-ion chromatography(IC)was thus developed for measurement of nitrite and nitrate in dairy products.Experimental parameters including extraction temperature,pH,extraction time,desorption solvent and time were optimized.Under the optimized conditions,the dynamic linear ranges of the developed PCTS/AuNPs-SBSE method were 0.005-0.5 mg/L and 0.02-5.0 mg/L for the nitrite and nitrate with enrichment factors of 22-25 folds,the correlation coefficients were 0.9985 and 0.9988,the limits of detections were 0.0012 mg/L and 0.0067 mg/L(S/N=3),and RSDs were in the range of 2.6%-7.2%(n=5),respectively.In the case of real samples analyses,the recoveries of spiked nitrite and nitrate were 84.7%-100.4%with RSDs of 2.8%-8.5%(n=3).The developed method was simple,sensitive and selective,and could be used for the analysis of nitrite and nitrate in dairy products.