表面增强拉曼光谱法测定牛奶中青霉素G钠的残留量

Determination of Penicillin G Sodium Residuein Milk by Surface Enhanced Raman Spectrometry

青霉素G钠(NaBP)溶液的常规拉曼光谱信号微弱.将制备的浓缩银纳米粒子(AgNPs)20μL与不同浓度(1×10^(-9)~1×10^(-1)mol·L^(-1))的青霉素G钠溶液(pH 6)20μL混合,所得混合液的表面增强拉曼光谱(SERS)信号显著增强,在上述混合液中加入1×10^(-2)mol􀅰L^(-1)硫酸镁溶液8μL,青霉素G钠SERS增强效果最佳.据此,提出了以AgNPs为基底,硫酸镁为凝聚剂,采用SERS测定青霉素G钠含量的方法,并用于加标牛奶样品的检测.结果表明,青霉素G钠浓度为1×10^(-8)~1×10^(-3)mol·L^(-1)时,其浓度的对数值与相应的SERS信号强度呈线性关系,检出限(3s/k)为8.2×10^(-9)mol·L^(-1).按标准加入法进行回收试验,回收率为80.0%~96.0%,测定值的相对标准偏差(n=5)为2.3%~6.5%.

The normal Raman spectrum signal of penicillin G sodium(NaBP)solution was weak.20μL of concentrated silvernanoparticles(AgNPs)prepared were mixed with NaBPsolutionindifferentconcentrations(1×10^(-9)-1×10-1 mol·L^(-1)),andsurfaceenhanced Ramanspectrometry(SERS)signal ofthe mixture obtained was significantlyenhanced.8μLof1×10^(-2)mol·L^(-1)magnesiumsulfatesolution wasaddedintotheabove mixture,and the SERSenhancementeffectof NaBP wasthe best.Therefore,a methodfor determinationof NaBP by SERS with AgNPs as substrate and magnesium sulfate as coagulant was proposed,and this method was applied for determination of NaBPresiduein milk.Asshown bytheresults,linearrelationship betweenthelogarithm of NaBP concentrationandthecorresponding SERSsignalintensity wasfoundintherange of1×10^(-8)-1×10^(-3)mol·L^(-1),with detectionlimit(3s/k)of 8.2×10^(-9)mol·L^(-1).Test for recovery was made by standard addition method,givingresultsintherange of80.0%-96.0%,with RSDs(n=5)ofthe determined valuesintherange of 2.3%-6.5%.