Objective To establish the method of determination of 3-monochloropropane-1,2-diol (3-MCPD) in grease food by gas chromatography-mass spectrometry (GC-MS).Methods 3-MCPD in grease food represented by bean paste was extracted by ultrasound,purified by alkaline earth solid phase extraction column,derivatived using phenylboronic acid (PBA) and detected by GC-MS.Results The linearity of 3-MCPD ranged from 1-100 ng/mL,with correlation coefficient at 0.9993.The limits of quantitation(LOQ) in soy sauce,bean paste,pepper oil were 0.6,0.5 and 7.0 μg/kg and limits of detection (LOD) were 1.9,1.6 and 18.8 μg/kg,respectively.Average recovery rate and relative standard deviation was 78.3％-106.7％ and 1.9％-11.6％ (n =6),when 3-MCPD was added in grease food at 2.5-1000 μg/kg.Conclusion The method has good purification effect and the detection sensitivity and accuracy,and can be used for the determination of 3-MCPD in grease food.

Objective To establish an isotope dilution gas chromatography-mass spectrometry(GC-MS)for the determination of chloropropanol esters in fried foods.Methods A total of 88 fried food samples were collected from supermarket,breakfast shop and street breakfast,stalls,the fried food sample with no chloropropanols esters detected was used as the blank sample. Samples were extracted using a solvent extraction method,followed by ester-bond cleavage reaction with sodium methylate-methanol and purification by diatomite solid-supported liquid-liquid extraction column. The derivatives in purified solution was detected by GC-MS after being derivatived with heptafluoro butyrylimidazole. The concentration of chloropropanols esters was quantified by using deuterium isotopes as internal standards. The accuracy of the method for evaluating recovery rate of blank samples was adopted,and the relative standard deviation(RSD)of the recovery rate represents the precision of the method.Results The 3-MCPD ester and 2-MCPD ester had good linear relationship in the concentration range of 25-1000 g/L(r>0.9995). The detection limits of 3-MCPD ester and 2-MCPD ester were 20μg/kg. The recovery rate of fat extracts from blank samples at 25,50,100,and 200μg/kg levels ranged from 89.7% to 103.7%,and RSD<8.4%. The detection rates of 3-MCPD ester and 2-MCPD ester in 88 samples were 81.82% and 70.45% respectively,and the content ranges from not-detected(ND) to 1.65mg/kg and to 0.93 mg/kg respectively.Conclusion The method is simple,accurate and reliable. It is suitable for the determination of chloropropanol esters in fried foods. There is a certain degree of contamination of chloropropanol esters in fried foods,and this comtamination is quite common.

Aluminium was measured in 2580 samples of 15 food groups and dietary exposure was estimated. Samples were purchased and analysed during 2010 to 2014. High aluminium levels were found in jellyfish (mean 4862mg/kg), laver (mean 455.2mg/kg) and fried twisted cruller (mean 392.4mg/kg). Dietary exposure to aluminium was estimated for Zhejiang residents. The average dietary exposure to aluminium via 15 food groups in Zhejiang Province was 1.15mg/kg bw/week, which is below the provisional tolerable weekly intake of 2mg/kg bw /week. Jellyfish is the main Al contributor, providing 37.6% of the daily intake via these 15 food groups. This study provided new information on aluminium levels and assessment of aluminium (Al) dietary exposure in Zhejiang Province of China.

Objective Toinvestigatethecontentofintrinsicformaldehydeinsea-food,soastoprovideascientificbasis forestablishingthecriteriaforformaldehyderesidueinsea-foods.Methods Atotalof266samplesofvarioussea-foods were collected from 3 representative coastal regions in Zhejiang Province.The content of intrinsic formaldehyde was examined at pre-determined gradients based on different storage temperature and time.A total of 825 test results were collected.All samples were carefully protected against contamination of exogenous formaldehyde in the process from collectiontoexamination.Results Theconcentrationofformaldehyderangedbetween10.40and223.80,0.08and3.50, 0.08 and 1 4.20,0.08 and 2.89,0.25 and 1 1.02,0.1 2 and 2.61 ,0.08 and 2.37 mg/kg for Bombay duck,yellow croaker,squid,hairtail,inkfish,octopus,and shrimp respectively.The intrinsic formaldehyde content varied between different sea -foods,and also between different individuals of a same species.Meanwhile,storage time significantly influencedintrinsicformaldehydecontentofsea-foods.Conclusion Sea-foodscontainedcertainamountofintrinsic formaldehyde.The national standard which requires zero content of formaldehyde in marine products needs further discussion.

目的 建立大气PM2.5中3种硝基多环芳烃的气相色谱-串联二级质谱测定法.方法 大气PM2.5经石英滤纸采集,待测化合物用二氯甲烷-丙酮有机溶剂提取,提取液用旋转蒸发仪浓缩至1.0 ml;经中性硅胶柱净化,收集洗脱液浓缩至1.0 ml,用气相色谱-串联二级质谱法检测.结果 2-硝基荧蒽的检出限为2 ng/ml,3-硝基荧蒽、1-硝基芘的检出限为5 ng/ml;2-硝基荧蒽的最低检出浓度为1 pg/m3,3-硝基荧蒽、1-硝基芘的最低检出浓度为3 pg/m3(采样体积以1 500 m3计).3种硝基多环芳烃的加标回收率为88.5％ ～ 96.0％,相对标准偏差(RSD)为2.0％～5.2％.结论 该方法操作简便、灵敏度高,适用于PM2.5中3种硝基多环芳烃的测定.

The objective of this study was to establish a method for detecting fatty acid esters of chioropropanols [including 2-monochloropropane-1,3-diol (2-MCPD) ester and 3-monochloropropane-1,2-diol (3-MCPD) ester] in infant milk powder using isotope dilution and GC-MS. The fat fraction in infant milk powder samples was extracted and treated with sodium methylate methanol to cleave the ester bonds of the 2- and 3-MCPD esters. The resultant 2- and 3-MCPDs in the samples were purified with matrix solid phase liquid liquid extraction and derivatized with heptafluorobutyryl imidazole for GC-MS analysis. Standard samples of deuterium isotope labeled 2- and 3-MCPD palmitic acid double esters and stearic acid double esters were used as the internal standards. We also detected 2- and 3-MCPD ester contents in 88 commercial samples of infant formula milk powder using this system. The detection system we established showed a good linearity of 2- and 3-MCPD ester contents in serially diluted standard solutions within the concentration range 25-1000 mu g/L, with r(2) > 0.9995 and an LOD of 30 mu g/kg for both of the MCPD esters. The recoveries of the two MCPD esters spiked at 25, 50, 100, and 200 mu g/kg in blank infant formula milk ranged from 98.2 to 110.5%, with RSDs <4.8%, suggesting good accuracy and reliability of this method. In the 88 commercial infant formula milk powder samples, the mean content of 2-MCPD ester was 41 mu g/kg (0-52 mu g/kg) and that of 3-MCPD was 185 mu g/kg (0-316 mu g/kg). Based on these results, we estimated the exposure levels of the two MCPD esters in infants fed on formula milk, and the results indicate potential health risks of consuming formula milk products contaminated by the two MCPD esters.

目的 建立超高效液相色谱-串联质谱法(UPLC-MS/MS)同时测定鸡肉、鸡蛋中氯霉素(CAP)和甲硝唑(MNZ)的检测方法.方法 以氘代氯霉素(D5-CAP)和氘代甲硝唑(D4-MNZ)为内标,样品采用乙酸乙酯提取,氮气吹干后用0.1 mol/L HCl复溶,正己烷脱脂,MCS固相萃取柱净化处理.在ACQUITYBEH-C18色谱柱中分离,以0.05％氨水-乙腈做流动相,梯度洗脱,氯霉素采用ESI-监测模式、甲硝唑采用ESI+监测模式,均采用同位素内标法定量.结果 鸡肉、鸡蛋样品中氯霉素和甲硝唑的检出限均为0.01 μg/kg;氯霉素的回收率为101.4％～104.3％,相对标准偏差为3.0％～9.1％;甲硝唑的回收率为101.0％～104.9％,相对标准偏差为4.4％ ～8.8％.结论 本法具有良好的选择性、灵敏度和准确度,满足鸡肉、鸡蛋样品中痕量氯霉素、甲硝唑药物残留的高灵敏分析.

目的建立全自动固相萃取-气相色谱法检测水中2,4-滴的方法。方法取1 L水样,加浓硫酸使水样p H＜1,通过全自动固相萃取仪以15 ml/min将水样过HLB固相萃取柱（Waters,500 mg,Oasis）萃取,用0.1 mol/L Na OH甲醇溶液洗脱HLB固相萃取柱上吸附的待测物,氮气吹干,用三氟化硼甲醇溶液衍生后,加纯水用正己烷提取,经气相色谱仪进行检测。结果水样中2,4-滴的浓度为0μg/ml~1.0μg/ml时,与峰面积呈良好的线性关系,相关系数（r）均＞0.999,最低检出浓度为0.01μg/L（1 L水样）。0.1μg/L加标水样组2,4-滴的回收率为110.0%,相对标准偏差（RSD）为6.9%;1.0μg/L加标水样组2,4-滴的回收率为106.0%,RSD为2.3%。结论该方法简便、准确,适用于水中2,4-滴的检测。

A sensitive and rapid analytical method based on alkaline diatomaceous earth extraction followed by GC/MS was developed for the quantitative determination of the toxic contaminant ethyl carbamate (EC) in yellow rice wines. The optimal extraction conditions were investigated. With the application of diatomaceous earth extraction, the damage of organic acids to the capillary column was greatly reduced. By using d5-EC as an internal standard for quantitative analysis of EC, the linearity of the calibration curves was good between 10 and 1000 ng/mL. The LOD and LOQ were 1.7 and 5.0 μg/kg, respectively. The spiked level of EC was 5.0-300 μg/kg, and the average recovery of the spikes was between 78.4 and 98.2%, with an RSD between 4.3 and 8.3%. Upon validation by five laboratories when spiked with 50, 100, and 300 μg/kg, the average respective recoveries were 102.9, 102.2, and 98.7% with a RSD between 0.7 and 8.1%. The validation results demonstrated that the method is fast, simple, selective, and suitable for the determination of EC in yellow rice wines.

A detection method for 19 kinds of phthalic acid ester compounds analyzed by n-hexane/ether/acetonitrile 1:7:8 v/v/v mixed solvent extraction, quick, easy, cheap, effective, rugged, and safe purification and internal standard method of quantitative gas chromatography with mass spectrometry was established. This method can effectively remove interfering materials, such as lipids, fatty acids, and pigments, from dairy products. The 19 kinds of phthalic acid ester compounds were within a 0.025-0.2 mg/kg range, the recovery rate was 65.2-125.7%, relative standard deviation was 7.9-15.4% (n = 6), and the limit of detection was 0.005-0.02 mg/kg. Concentrations of the 19 kinds of phthalic acid ester compounds ranged between 0.01 and 0.12 mg/kg in ten dairy materials and 20 dairy products. The established method is simple, rapid, accurate, and highly sensitive.

目的 采用直接稀释电感耦合等离子体质谱法(ICP-MS)测定人尿镉,并与WS/T 32-1996石墨炉原子吸收法(GFAAS)进行比较.方法 尿样经1％硝酸溶液稀释后,用ICP-MS直接测定;1％硝酸混合0.2％磷酸二氢铵溶液稀释后用GFAAS直接测定尿镉.同时用冻干人尿镉标准物质(ZK018-1、ZK018-2)作为质控样.结果 经t检验,P＞0.05,2种方法检测结果表示差异无统计学意义.结论 用GFAAS测定尿镉需要加入一定的基体改进剂,线性较窄,时间较长.用ICP-MS测定尿镉线性范围宽、抗干扰能力强、测定周期短,完全满足分析的要求,适用于日常样品的测定.

Ethyl carbamate (EC) was analyzed during yellow rice wine production and storage. EC increased slowly during fermentation and rapidly after frying and sterilization. Less amount of EC was formed when cooled rapidly to 30 °C than when cooled naturally. High temperature and long storage time increased EC formation. After 400 days storage, EC increased from 74.0 to 84.2, 131.8 and 509.4 μg/kg at 4 °C, room temperature and 37 °C, respectively, and there was significantly difference between the fried wine and the wine on sale from 2011 (p < 0.01). Urea increased during yellow rice wine fermentation and was above 20 mg/kg after the wine was fried; urea contributed to EC formation when the fried wine was cooled slowly. These results indicate that it is necessary for industry to optimize the wine frying conditions, such as temperature, time and cooling process in order to decrease EC formation.

Objective To establish a method for determination of maleic acid in starch products by GC /MS. Methods The samples were ultrasonicly extracted with ethanol,then centrifuged at high speed to get the supernatant. The supernatant liquid was methylated with boron trifluoride diethyl etherate solution,after cooling,the analytes were extracted by n-hexane for detection of maleic acid using GC-MS-SIM. Results The recovery rates of maleic acid in several starch products,such as starch,pork ball,rice noodles and QQ candy,were 89% ~ 99% with RSD 10%. Calculated on the sample amount of 2. 0 ml,the lowest detection limit was 1. 0 mg / kg. Conclusion The method has the advantages of easy operation,less interference,rapidity,accuracy and satisfying sensitivity,purification effect,so it could be used for determining maleic acid in starch products,and providing basic data for market supervision.

Objective A method was developed for the determination of 16 polycyclic aromatic hydrocarbons(PAH16) in edible oil by isotope dilution gas chromatography- mass spectrometry(GC- MS). Methods The isotope internal standards were added into the samples of edible oil,then heated in alkali solution for saponification. The target compounds of PAH16 were extracted by hexane,adsorbed and purified by neutral silica gel column,and detected by GC- MS. Results The 16 kinds of PAHs showed good linearity between concentration and peak area(r 0. 999). The detection limits of Naphthalene,Acenaphthylene,Acenaphthene,Fluorene,Phenathrene,Anthracene,Fluoranthene,Pyrene were 0. 2 μg / kg,while those of Benz[a]anthracene,Chrysene,Benzo[b]fluoranthene,Benzo[k]fluoranthene,Benzo[a]pyrene,Indeno[1,2,3- cd]pyrene,Dibenz [a,h]anthracene,Benzo[g,h,i]perylene were 0. 5 μg/kg. The recoveries were 85.7% ~125. 0%,and the relative standard deviations(RSDs) were 0. 9% ~ 9. 8%. Conclusion The method is quick and accurate for detection of PAH16 in edible oil.

A method for ethyl carbamate (EC) determination in alcoholic beverages and soy sauce was developed by GC-MS. We adopted the diatomaceous earth solid-phase extraction (SPE) column and elution solvent of ethyl acetate/diethyl ether (5:95 v/v) for sample cleaning. The in-house validation showed the limit of quantification (LOQ) was 5.0 μg/kg. In the accuracy assay, the total average recovery for was 96.7%. The relative standard deviations (RSDs) were <5%. Subsequently, a collaborative trial was organized for the further validation. The RSDs for repeatability and reproducibility were 1.2-7.8% and 2.3-9.6% respectively. It indicated that the present method performed well in different laboratories.

OBJECTIVE:To establish the method of simultaneous determination of methylcarbamate (MC) and ethylcarbamate (EC) in yellow rice wine by gas chromatography-mass spectrometry (GC/MS).METHODS:MC and EC in yellow rice wine were derived by 9-xanthydrol, and then the derivants were detected by GC/MS; and quantitatively analyzed by D5-EC isotope internal standard method.RESULTS:The linearity of MC and EC ranged from 2.0 µg/L to 400.0 µg/L, with correlation coefficients at 0.998 and 0.999, respectively. The limits of quantitation (LOQ) and detection (LOD) were 0.67 and 2.0 µg/kg. When MC and EC were added in yellow rice wine at the range of 2.0-300.0 µg/kg, the intraday average recovery rate was 78.8%-102.3%, relative standard deviation was 3.2%-11.6%; interday average recovery rate was 75.4%-101.3%, relative standard deviation was 3.8%-13.4%. 20 samples of yellow rice wine from supermarket were detected using this method, the contents of MC were in the range of ND (no detected) to 1.2 µg/kg, the detection rate was 6% (3/20), the contents of EC in the range of 18.6 µg/kg to 432.3 µg/kg, with the average level at 135.2 µg/kg.CONCLUSION:The method is simple, rapid and useful for simultaneous determination of MC and EC in yellow rice wine.

OBJECTIVE To understand the content status of ethyl carbamate (EC) in yellow rice wine and the changes in storage period and shelf life in Zhejiang province. METHODS A total of 475 samples of yellow rice wine purchased randomly from supermarkets and food stores in Zhejiang province during 2008-2012, and 49 samples collected from manufacturers were measured for EC content. The sample collected from manufacturers by filter sterilization was placed at 4 °C, room temperature and 37 °C for 400 d, respectively;a bottled wine and a wine in bag were bought from market were placed for 400 d in room temperature to conduct shelf life storage test, and measure the content in every point in 2011. The EC of the samples was determinated by gas chromatography-mass spectrometry after the samples were diluted with D5-EC isotope dilution technique, and purified by alkaline diatomite solid phase extraction column. RESULTS The overall detection rate of EC was 99% (472/475) in yellow rice wine of Zhejiang province in 2008-2012, the median value was 70-112 µg/kg, the 90th percentile was 190-333 µg/kg, the 95th percentile was 214-393 µg/kg, and the maximum value was 430-515 µg/kg. The content of EC was increased gradually along with the increasing of storage age in commercially yellow rice wine, and the average content of EC were positively correlated with storage age(r = 0.988). The contents of EC in yellow rice wine after sterilization increased from 74 µg/kg to 86 µg/kg, 127 µg/kg and 509 µg/kg at 4 °C, room temperature and 37°C, respectively for 400 d storage, the differences had statistical significance (F = 14.73, P < 0.01). The content of EC in yellow rice wines in shelf life, which stored in room temperature with bottle and bag package, was decreased slightly with increasing storage time in the beginning, from 215 to 184 µg/kg and 196 to 158 µg/kg, respectively, and increased again with increasing storage time after 250 d, with 252 µg/kg and 210 µg/kg in bottle and bag package after 400 d, respectively, the differences had statistical significance (Z = 2.37, P < 0.05). CONCLUSION EC is widespread in rice wine, the content of EC was correlated with storage time and temperature.

The main raw materials of rice wine,production process,storage process of EC content were tested,Found in fried wine,storage process EC content will appear to rise apparently.

Objective:To understand the variation tendency of aluminum in cereal products and to assess dietary exposure.Methods: One thousand,four hundred and one samples of fried bread stick,steamed bread and other food products in Zhejiang province during 2006-2010 were monitored and assessed using point evaluation of food consumption dietary nutritional survey.Results: The detection rate of aluminium was 92.2%(1292/1401),and 50.7% of the samples exceeded the national limit(711/1401);The average aluminum content decreased to 126.0 mg/kg in 2010 from 541.3 mg/kg in 2006.The over-limit rate of aluminium contents in fried cake decreased to 37.2% in 2010 from 100% in 2006.The over-limit rate of aluminium in the steamed buns and other food products increased from 50.0% in 2006 to 70.6% in 2010.The adult daily intake of aluminium from the steamed buns increased to 14.77 mg in 2010 from 3.32mg in 2006.Proportion of ADI increased to 25 percent in 2010 form 5.53 percent in 2006.Conclusion: It is suggested to strengthen the administration of aluminium-containing additives in staple food,and control the misuse of aluminium-containing additives in steamed bread and other staple products.