固相萃取光谱法测定水及肉制品中痕量亚硝酸钠

采用固相萃取光谱法对亚硝酸钠进行定量分析.首先确定分析波长为472.5 nm,随后优化衍生化反应的条件:pH 4.74、衍生化时间15 min、衍生化试剂亚硝酸钠-对氨基苯磺酸-1-萘酚物质的量比1∶3∶3.富集条件:富集膜种类为尼龙膜,过膜体积为10mL.在0.002～0.030 mg/L质量浓度范围,吸光度y与质量...

Spectroscopic Determination of Trace Nitrite in Water and Meat Following Solid Phase Extraction

A spectroscopic method was used for the quantitative analysis of sodium nitrite after solid phase extraction. The analytical wavelength was set at 472.5 nm, and the derivatization conditions were optimized as follows: pH 4.74, derivatization time 15 min, and derivatization reagent composition sodium nitrite:p-aminobenzenesulfonic acid:1-naphthol molar ratio of 1:3:3. Enrichment was accomplished using a nylon membrane with a loading volume of 10 mL. In the concentration range of 0.002–0.030 mg/L, the absorbance (y) had a quadratic relationship with nitrite concentration (x), expressed as y = ?268.76x2 + 14.55x + 0.03, with a correlation coefficient (R2) of 0.999, and the limit of detection (LOD) of the presented method was 1.29 μg/L. The method was applied to the detection of NaNO2 in tap water with spiked recoveries of 91.3%–114.0%, and relative standard deviations (RSDs) of 4.21%–7.90%. The results of this method for sodium nitrite in bacon agreed with those of ion chromatography, with standard deviations of 8.51% and 9.98% in parallel experiments on American-style and Shuanghui-branded bacons, respectively. This study has provided a rapid, sensitive, accurate and precise method for the determination of NaNO2 with high selectivity.