面粉中滑石粉的现场快速检测方法及其装置研究

Rapid Detection Method of Talc Powder in Flour

为建立面粉中滑石粉的现场快速检测方法,并研制出便携式检测装置,实现现场快速检测,通过实验摸索出适合的消化剂配方,即V(H_2SO_4):V(HClO_4):V(HNO_3)=1:1:4;将样品经1 mol/L HCl清洗、加热消化后,取反应液,通过镁试剂的显色反应,定性地判断样品中是否加入滑石粉。结果表明:用样量为1g时,此方法的检出下限为1%,检测时间在40 min左右,重复性较好,假阳性率2.5%,假阴性率2.5%,反应可在密闭的便携武装置内进行,实现现场、快速、无污染检测。

A method and a set of portable equipment for rapid detection of talc powder in flour on the spot was developed. Appropriate digestant （vitrol ： perchloric acid ： nitric acid= 1 ： 1 ： 4 ） was selected to digest talc powder . After the sample was washed by 1mol/L HCl and digested during heating, p-nitrobenzene azoresorcinol was added into and the change of colour showed whether there was talc powder in the samples. With good repeatability, when the sample was lg,detection limit of this method was 1% and detection time was about 40 min,false positive rate 2.5% ,false negative rate 2.5%. Airtight equipment was designed according to this method. Conclusion. The method and the equipment could be practically applied for its accuracy , rapidity and briefness.