辣椒粉、辣椒酱、腐乳、辣条、鸭蛋、橙子等样品经正己烷提取、浓缩,用5 mL环己烷:乙酸乙酯为1:1复溶残渣,经0.45μm有机滤膜过滤后,上凝胶色谱仪净化,分别采用高效液相色谱仪(LC)和液相色谱三重四级杆串联质谱仪(LC/MS/MS)进行仪器分析,外标法定量,该方法的精密度和准确度均较好,适用于各类食品中苏丹红的检测.

建立一种准确、 快速的测定大米中农药马拉硫磷残留的方法.经丙酮溶液提取,用石墨化碳黑小柱和氟罗里硅柱双柱结合净化,氮吹浓缩,然后用气相色谱-质谱联用(GC-MS)检测.马拉硫磷标准质量浓度在0.1～1.0 mg/L范围内,线性关系良好,相关系数r达0.998.添加质量分数为0.1～1.0 mg/kg时,回收率在91.8％～119.5％,相对标准偏差(RSD)在3.1％～8.5％,定量检出限达0.05 mg/kg.新建的GC-MS法操作简单、 净化效果好、 灵敏度高、 检测效果良好.

建立了高效液相色谱与原子荧光联用技术测定食用菌中无机汞、甲基汞、乙基汞形态的分析方法.对试样的前处理方法及液相色谱和原子荧光的最佳参数进行了优化,结果表明:在优化条件下,3种汞化合物的线性范围在0~50μg/L时,相关系数均优于0.999,检出限在0.008~0.024 mg/kg之间;方法的RSD均小于7%,加标平均回收率在75%~97%之间.该方法前处理简单、检出限低、准确度高、杂质干扰少、检测费用低、耗时短,适用于普通实验室对食用菌中不同形态汞的检测分析.

采用顶空固相微萃取(HS-SPME)和气相色谱质谱联用技术(GC/MS),建立了测定奶茶中香兰素和乙基香兰素的分析方法.选取了75 μm carboxen/聚二甲基硅氧烷(CAR/PDMS)萃取纤维,考察了萃取温度、萃取时间和盐浓度等因素对萃取效率的影响.采用3,4-亚甲二氧苯乙酮作为内标,对香兰素和乙基香兰素进行定量.结果表明,在检测范围0.5～25.0 μg内,该方法对香兰素(R2=0.9974)和乙基香兰素(R2 =0.9987)具有良好的线性关系,固体样品中香兰素和乙基香兰素的检出限分别为0.5 mg/kg和0.3 mg/kg,液体样品中检出限分别为0.05 mg/kg和0.03 mg/kg,香兰素的平均回收率为88.99％ ～105.15％,相对标准偏差(RSDs)为2.40％ ～9.26％,乙基香兰素的平均回收率为91.57％～105.13％,相对标准偏差为2.35％～8.49％.该方法操作简便、准确可靠,适合于奶茶中香兰素和乙基香兰素的分析要求.

采用超高效液相色谱-稳定性同位素稀释质谱法测定米线中的乌洛托品,对测试过程的不确定度来源进行系统分析,建立不确定度评估的数学模型,通过对不确定度各主要分量的分析计算,得出合成不确定度和扩展不确定度.当乌洛托品的测定结果为0.821 mg/kg时,扩展不确定度为0.079 mg/kg,k=-2.该评估模型为同位素稀释质谱法的不确定度评估提供了参考依据.

本文建立了一种气相色谱(GC)和气相色谱-质谱(GC-MS)法测定饮料中香兰素和乙基香兰素含量的方法.无色样品经乙醚萃取、离心、取上清液浓缩定容经0.22 μm有机相滤膜净化进样,有颜色样品经乙醚萃取、离心、取乙醚上清液浓缩至近干,丙酮溶解混匀,过石墨化碳黑柱净化,浓缩定容,分别进GC-FID和GC-MS测定及确证,外标法定量.GC法测定香兰素和乙基香兰素的添加回收率范围为80％ ～105％,相对标准偏差(RSD)小于6.0％.GC-MS法测定香兰素和乙基香兰素的添加回收率范围为81％～110％,相对标准偏差(RSD)小于6.0％.该方法中GC仪器操作简单、成本较低,可广泛应用于饮料中香兰素和乙基香兰素日常检测,GC-MS法采用选择离子扫描(SIM)排除GC法测定的假阳性结果,使测定结果更准确可靠,两种方法互补使用,适合饮料中香兰素和乙基香兰素的日常分析检测和质量控制.

A gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) method was developed for the determination of methenamine in dairy products. Methenamine-(C6N4)-C-13-N-15 isotopic reference material was used as an internal standard to quantify the methenamine. The conditions of the extraction, solid phase extraction (SPE) and GC-MS/MS were optimized. Linear calibration curves were obtained over the calibration range of 1-100 mu g/L (R-2 = 0.9992). The limit of detection CLOD) was 2 mu g/kg in the liquid sample and 8 mu g/kg in the solid sample. The limit of quantification (LOQ) was 5 mu g/kg in the liquid sample and 25 mu g/kg in the solid sample. The average recovery of methenamine in dairy products varied from 93.3 to 102.3%. Method validation parameters, including precision and accuracy, were also evaluated. The intra-day precision ranged from 2.0 to 6.8%, with the accuracy varying from -6.7 to +2.3%. The inter-day precision ranged from 3.0 to 8.3%, with the accuracy varying from -8.5 to +1.6%. The method was applied to analyze forty-two dairy samples collected in Yunnan. The values of methenamine were observed from 11 to 18 mu g/kg in milk samples, and 622-7310 mu g/kg in cheese samples. Results of the stability test indicated that methenamine was more stable in milk powder than milk and cheese. (C) 2015 Elsevier Ltd. All rights reserved.

采用超高效液相色谱-串联质谱法(UPLC-MS/MS)和稳定性同位素稀释技术,建立了测定腐竹中乌洛托品的分析方法.以乙腈为提取溶剂,向腐竹样品中加入乌洛托品的稳定性同位素,经固相萃取柱净化,采用HILIC色谱柱分离,目标物在UPLC-MS/MS的多反应监测(MRM)模式下,内标法定量.该方法在1～40 μg/L范围内有良好的线性关系,相关系数为0.9996,方法定量限为2μg/kg.在添加水平为2、10、30μg/kg时,平均回收率为97.8％ ～101.5％,相对标准偏差(RSD)为1.9％～4.8％.本方法灵敏度高,准确度和重复性好,可为作为检测腐竹中违法添加乌洛托品的方法.

Objective To establish a rapid and sensitive high performance liquid chromatography method for determination of demethyl fumarate in seasoned flour products. Methods Chromatographic column was ODS-C18 4.6 mm×250 mm. The mobile phase was methanol 0.02 mol/L ammonium acetate (55:45, v:v). Sample was crushed and extracted with ammonia water methanol solution; pH value was adjusted to 6 with hydrochloric acid;0.45μm membrane was used for filtration after ultrasonic extraction. Then, the sample was injected into high performance liquid chromatography, the component was qualitatively determined by retention time and quantitatively determined by peak area. Results Under the optimal conditions, the method showed a good linearity in the range of 0.25~10.0 mg/L, and the correlation coefficient was 0.9995. The limit of detection was 0.03 mg/kg, and the limit of quantification was 0.1 mg/kg. The recovery percentages varied from 94.0% to 102.5% and relative standard deviations were in the range 3.6%~5.2%. Conclusion The method was proved to be satisfactory in precision, accuracy and sensitivity, and without the distraction of impurities. It can be used to detect demethyl fumarate in seasoned flour products.

A method for the determination of BHA,BHT and TBHQ in edible vegetation oil by gas chromatography coupled with triple quadrupole mass spectrometry(GC/QQQ/MS/M S)was studied.The linear range of detection changed from 0.5 μ g/L to 50 μ g/L(r> 0.999).The detection limits of machine of the three kinds of antioxidants were 0.1 μ g/L,0.04 μ g/L and 0.2 μ g/L and those in the sample were 0.1mg/ kg,0.04mg/kg and 0.2mg/kg.The recoveries of three different concentrations(0.5,5and 50mg/kg) were ranged between 85.0%-110.0% and the relative standard deviations were ranged from 2.53%to 8.37%.This method is simple,quick,accurate and safe.The method can be applied in determination of BHA,BHT and TBHQ in edible vegetation oil samples with satisfactory results.

Objective: To establish a method for simultaneous detection of three species of foodborne pathogenic bacteria using liquid gene chips.Method: Three sets of specific primers and probes were designed according to the gene 23S rDNA of Staphylococcus aureus,the gene iap of Listeria monocytogenes and the gene ipaH of Shigella spp.The multiple PCR reaction systems gave rise to target fragments of 246,112 bp and 174 bp,respectively.The target fragments were captured by microspheres coupled with the gene-specific probes,finally establishing liquid gene chips.Results: The method was highly sensitive and specific.The sensitivity for Staphylococcusaureus,Listeria monocytogenes and Shigella spp.were 38,44 CFU/mL and 21 CFU/mL,respectively.Conclusion: We here report a novel detection assay using liquid gene chips for three foodborne pathogenic bacteria,which provides a highthroughput system for rapid detection of foodborne pathogenic bacteria.

A method for the determination of Benzo( a) Pyrene in animal fat by gas chromatography-triple quadrupole mass spectrometry( GC- MS / MS) was studied. The linear range of detection changed from 0. 1 μg / L to 10 μg / L( r = 0. 997). The limit of quantitation in the samples was 0. 4μg /kg. The recoveries of three different concentrations( 0. 4,4. 0and 40. 0 μg /kg) were 87. 9% ~108. 3 % and the relative standard deviations were 2. 2 % ~ 9. 3 %. This method is simple and accurate and it has been applied to the determination of Benzo( a) Pyrene in samples with satisfactory results.

利用气相色谱-三重四级杆质谱联用技术,建立了动物油脂中苯并(a)芘的检测方法.分析结果表明,该方法对动物油脂中苯并(a)芘的检测线性范围为0.1 ～20 μg/L,相关系数为0.997,样品定量检测限为0.4 μg/kg.添加三个浓度梯度(0.4、4.0和40.0 μg/kg)的样品平均回收率在87.9％～108.3％之间,相对标准偏差在2.2％～9.3％之间.该方法简便、准确,应用于实际样品中的测定结果令人满意.

目的建立酒类食品中17种邻苯二甲酸酯的气相色谱-串联质谱检测方法,并对市场上不同类型酒类食品邻苯二甲酸酯含量的分布情况进行分析。方法用正己烷提取样品,气相色谱-串联质谱定量分析。结果线性范围为5~10000μg/L,相关系数大于0.999,仪器检出限为0.1~25μg/L,样品的检出限为0.001~0.1 mg/kg。3个浓度梯度(0.3、3.0、30.0 mg/kg)的平均回收率在83.7%～105.9%,相对标准偏差(RSD, n=6)在1.9%～5.7%。抽样结果显示配制酒中邻苯二甲酸酯检出率较其他类型酒类高。结论此方法灵敏度高、准确、重现性好,适用于酒类食品中邻苯二甲酸酯的检测。

Recent international and domestic quantitative and qualitative determination methods of melamine and its analogues were introduced. The international and domestic standard methods,reported methods,rapid screening analysis methods and precautions about these methods were described.

A method for determination of Neotame in Distilled Spirit by high performance liquid chromatography (HPLC) has been established. Ethanol is removed by heating with boiling water and constant volume to the corresponding volume with water. Neotame is determined by HPLC with the factors such as the detector DAD, the column of Agilent Eclipse XDB-C18 (4.6 mm × 250 mm, 5 um), mobile phase ratio (Vacetonitrile : Vion pair buffer solution = 25:75), sample size 20 uL, the temperature of the column at 30℃ and testing wavelength at 218 nm. It is quantified using external standard. The recoveries of the method with satisfactory precision ranged from 97% to 102%. This method is simple and suitable for the determination of Neotame in distilled Spirit.