Study On Detection Of The Use Of Methenamine In Starch Products With SERS

Surface Enhanced Raman Spectra (SERS) is a new material compositiondetection technology which is widely used in biology, medicine and food detectiondue to its high sensitivity and high recognition rate of the sample. Food safetyissues in recent years is imminently, SERS technique because of its rapid, on-site,real-time, economic advantages are widely used in all kinds of food safety testing.In this thesis the mainly research object is the illegal additives methenamine inthe vermicelli. and choose silver sol made by using the method of chemicalreduction as the active substrate to detect the used methenamine samples of SERS.Its particle distribution is tested by using the particle particle detector, and a goodmonodispersity is achieved. At the same time, the stability of the prepared silver solis tested, and concluded that the silver sol can preserve for a long time, which isgood for preparation in advance, and can improve detection speed.Using the silver sol as enhanced base, the aqueous solution of methenaminewith nitric acid and sodium was detected respectively, and found that the situationof using nitric acid detection lower limit is about10-5g/ml. The effect is obviouslybetter than the the situation of using sodium chloride, so the sodium chloride wastaken as the coagulation accelerator in this thesis. Then in the situation of lowconcentration, the different addition amount of chlorine ion, samples of the sameconcentration and the sol with ratio, Ph changes under the same concentrationsystem used for SERS signal is studied and discussed respectively.The influence of signal strength was studied under the added order of the sol,samples and sodium chloride. By using the above conclusion the optimal conditionswas achieved under the low concentration aqueous solution of methenamine, and agood signal strength was got around the raman characteristic peak of1052cm-1from10ppb to0.1ppb. The detection threshold of its aqueous solution is about0.1ppb,which shows the detection method for methenamine detection has a great applypotential. Then simulation of the actual amount vermicelli samples containingcorresponding methenamine were tested, the detection limit is about10PPM.Processing of the operation and measurement process are safe and pollution-free,the pretreatment process is simple, and the whole detection process can becompleted in20minutes. SERS technique provides a simple, rapid and efficientdetection method for the methenamine on-site real-time detection.