液态奶中硫氰酸钠快速检测试剂盒的研制与应用

硫氰酸钠(NaSCN,Sodium thiocyanate)是一种具有防腐作用的化工原料,常被加入乳制品中以延长其货架期,增大了安全风险。目前已报道的硫氰酸钠快速检测方法,大多存在底色干扰严重和灵敏度低等弊端。为提高检测灵敏度,本研究基于SCN~-可与Fe~(3+)反应生成血红色络合物的原理,通过显色显色剂筛选、显色条件优化,以模拟奶模拟牛奶基质,经样品前处理、显色剂显色,建立了一种NaSCN半定量速测管法,并开发为快速检测试剂盒,用于液态奶样品中硫氰酸钠残留量检测。结果表明,最佳显色条件为:以2 mol/L硝酸铁(2 mol/L硝酸作溶剂)作为显色剂,常温下2 min内显色完全。该试剂盒对液态奶中硫氰酸钠残留的检出限为5 mg/kg;5~100 mg/kg时,区分度良好;准确、灵敏、快速(5 min)、稳定,无需仪器辅助,适合中小型企业与基层单位现场对大批量样品进行筛查。

Development and Application of Rapid Determination Kit for Sodium Thiocyanate in Liquid Milk

Sodium thiocyanate (NaSCN), a chemical raw material with preservative effect, was often used in dairy products to extend the shelf life, which increased the safety risk. The rapid detection methods for sodium thiocyanate that had been reported had several drawbacks such as serious background interference and low sensitivity. A NaSCN semi-quantitative rapid detection method was established in this study with the principle of sanguineous complex reaction induced by SCN- and Fe3+ by selecting the chromogenic agent, optimizing chromogenic reaction conditions, simulating milk matrix, pretreating samples and the chromogenic reaction. The rapid determination kit for sodium thiocyanate residues in liquid milk samples was developed. The optimum conditions were as follows: the chromogenic agent, 2 mol/L iron nitrate (2 mol/L nitric acid as the solvent); reaction time, 2 min. The reaction was complete in room temperature under the optimum conditions. The detection limit of the kit for sodium thiocyanate residues in liquid milk was 5 mg/kg, and the color gradient was well distinguished in the NaSCN concentration of 5~100 mg/kg. The proposed kit was accurate, sensitive, rapid (5 min), stable and not in need of instrument assistance, and wad suitable for on-site screening a large quantities of liquid milk samples for small and medium-sized enterprises and basic units.