超高效液相色谱-串联质谱法同时测定水体中莠去津和呋喃丹的含量

水样中莠去津和呋喃丹通过C18固相萃取柱使之分离并富集。用氮气将固相萃取柱吹干后,用二氯甲烷淋洗使被测组分洗脱,所得洗脱液用氮气吹至尽干,用混合溶剂[甲醇与甲酸-水(0.1+99.9)溶液按40比60的比例混合]1 mL溶解残渣,所得溶液供超高效液相色谱-串联质谱法(UPLC-MS/MS)分析用。用Waters BEH C18色谱柱作分离柱,用不同比例的甲醇和甲酸-水(0.1+99.9)溶液的混合液作流动相进行梯度淋洗,使上述两种农药分离后进行串联质谱测定,所用质谱条件为电喷雾离子源,正离子扫描和多反应监测模式。两种农药质量浓度均在0.10~10.00μg.L-1范围内与相应的峰面积值呈线性关系,检出限(3S/N)均为0.15 ng.L-1。在3个浓度水平上(0.10,0.50,5.00μg.L-1)加入两种农药的标准溶液进行回收试验,测得其平均回收率在77.0%~102.2%之间,相对标准偏差(n=5)在2.9%~7.6%之间。     

Bond Elut PBA固相萃取柱净化-高效液相色谱-串联质谱法同时测定鸡肉中金刚烷胺和利巴韦林的残留量

取鸡肉样品约2.0 g,加入100μg·L^-1金刚烷胺-d₆和利巴韦林-¹³C₅的混合内标溶液100μL和体积比为7∶3的20 g·L^-1三氯乙酸溶液-乙腈的混合溶液15 mL,涡旋30 s,振荡15 min,离心5 min,上层有机相转移至50 mL离心管中。重复上述操作一次,合并上层有机相,过普通滤纸,滤液用约100μL氨水调节酸度至pH 8.5,过活化好的Bond Elut PBA固相萃取柱。固相萃取柱先以体积比1∶9的乙腈-0.25 mol·L^-1乙酸铵混合溶液3 mL和含5%(体积分数)氨水的甲醇溶液3 mL淋洗,然后以含2%(体积分数)甲酸的甲醇溶液4 mL洗脱。收集洗脱液,氮吹至干,残渣用体积比1∶9乙腈-水混合溶液1 mL复溶后,过0.22μm滤膜。滤液进入高效液相色谱-串联质谱仪,在Eclipse XDB-C₈色谱柱上用不同体积比的含5 mmol·L^-1乙酸铵的1%(体积分数)甲酸溶液-甲醇-水...     

超高效液相色谱-串联质谱法测定印刷电路板中全氟辛烷磺酸盐

经剪碎和粉碎的印刷电路板样品用甲酸-甲醇(0.1+99.9)溶液超声提取,所得提取液于45℃旋转蒸发至1mL,加水5mL,用稀甲酸或稀氨水调节溶液的pH值为4～5。将溶液通过Oasis WAX固相萃取小柱净化,用甲酸(2+98)溶液和甲醇先后清洗小柱后,用氨水-甲醇(2+98)混合溶液洗脱,将全部洗脱液氮吹蒸发至近干,用流动相溶液定容为1mL供测定。所用色谱柱为Acquity UPLC BEH C18柱,柱温30℃,进样量为5μL。由5mmol.L-1乙酸铵溶液及乙腈(60+40)混合溶液作为流动相,在0.3mL.min-1流量条件下进行洗脱。质谱测定中采用ESI负电离方式,多反应监测扫描模式。测得全氟辛烷磺酸盐质量分数在1.0～1 000μg.kg-1范围内与峰面积值呈线性关系,测定下限(10S/N)为1.0μg.kg-1。用标准加入法测得回收率在89.0%～99.3%之间。     

固相萃取-超高效合相色谱法测定猪肉中氟苯尼考对映体及其代谢物氟苯尼考胺的含量北大核心CSCD

在10.0 g猪肉样品中加入含3%(体积分数)氨水的乙酸乙酯溶液25 mL,涡旋1 min混匀,离心5 min,所得沉淀用上述方法再重复提取一次。合并两次提取液,于40℃减压浓缩至近干,用10 mL磷酸盐缓冲溶液(pH 6.0)溶解残渣。所得溶液过活化好的HLB固相萃取柱,用10 mL水淋洗,真空抽柱1 min,用6 mL甲醇洗脱。收集洗脱液,于40℃氮吹至近干,加入体积比8∶2的正庚烷-异丙醇混合溶液1 mL,涡旋3 min溶解残渣,过0.22μm有机滤膜,滤液供超高效合相色谱仪分析。采用CHIRALPAK AD-3手性色谱柱作固定相,设置柱温40℃,系统背压13.8 MPa,以不同体积比的超临界二氧化碳和含0.5%(体积分数)氨水的甲醇溶液的混合溶液为流动相进行梯度洗脱,在检测波长224 nm处用外标法测定(-)-氟苯尼考、(+)-氟苯尼考及它们的代谢物氟苯尼考胺的含量。结果显示:3种目标化合物的质量浓度在0.50~20.00 mg·L^(-1)内与其对应的峰面积呈线性关系,测定下限为0.05 mg·kg^(-1)[(-)-氟苯尼考和(+)-氟苯尼考]和0.1 mg·kg^(-1)(氟苯尼考胺)。以阴性猪肉样品为基质进行3个浓度水平的加标回收试验,3种目标化合物的回收率为81.2%~107%,测定值的相对标准偏差(n=6)为5.0%~9.0%。方法用于20份猪肉样品的分析,仅在1份样品中检出(-)-氟苯尼考(248μg·kg^(-1))。     

超声提取-高效液相色谱法测定粗榧中高三尖杉酯碱

用乙醇(每克样品加15 mL)超声提取40 min使粗榧中高三尖杉酯碱溶出.每一样品先后提取3次,所得提取液经合并,减压蒸发并定容为10.0 mL供高效液相色谱分析用.在色谱测定中,采用Diamonsil C18色谱柱作为固定相,采用0.08 mol·L-1乙酸铵溶液和甲醇以55比45的体积比混合的溶液作为流动相.紫外检测的波长为291 nm,对方法的精密度和回收率分别作了试验,测得其相对标准偏差(n=5)为8.08%.     

气相色谱-串联质谱法快速测定禽蛋中203种农药及化学污染物残留

建立了禽蛋中203种农药及化学污染物残留的气相色谱-串联质谱(GCMS/MS)检测方法.样品用乙腈振荡提取,经ODS C18+Carb串联固相萃取柱净化,乙腈-甲苯(3:1,v/v)洗脱,洗脱液浓缩至0.5mL,氮吹至近干,加1mL正己烷超声溶解后,在气相色谱-串联质谱多反应监测(MRM)模式下进行测定.在1倍MRL(...     

固相萃取-原子荧光光谱法测定大米中无机硒的含量

建立了固相萃取-原子荧光光谱法测定大米中无机硒含量的方法.大米粉样品0.5 g用水20 mL提取,离心后上清液中加入5 g·L-1氢氧化钠溶液,调至pH 4～7,过滤即得提取液.将提取液上SAX强阴离子交换柱进行固相萃取,收集洗脱液10 mL以分离无机硒,再采用原子荧光光谱法测定大米中无机硒的含量.结果表明:无机硒的质...     

气相色谱-串联质谱法测定茶叶中10种酸性除草剂的残留量

取茶叶样品5.00g,用水[预先用50%(体积分数)盐酸溶液调节其酸度至pH 2.0]10.0mL浸泡30min。先后用乙腈超声提取2次(每次用乙腈20.0mL),每次20min,离心,合并两次提取的上清液,先后于30℃水浴中减压蒸发以及在常温下吹氮至溶液近干,加入乙腈-甲苯-乙酸(75+25+1)混合溶液(简称为ATA混合液)5.0mL溶解残渣,此溶液流经Cleanert Pestic Carb/NH2固相萃取柱净化。收集流出液(主液),用ATA混合液15.0mL淋洗萃取柱,收集流出液并与主液合并,在常温条件下吹氮至近干。加入丙酮870μL溶解残渣。按文献报道的方法进行五氟苄溴(PFBBr)衍生化于60℃水浴中反应1.0h,用正己烷1.0mL提取所生成的衍生物。按所选条件用气相色谱-串联质谱法测定提取液中10种酸性除草剂的残留量。结果表明:10种酸性除草剂化合物的质量浓度在一定范围内与其峰面积之间呈线性关系,检出限(3S/N)在0.022 3～1.54μg·kg~(-1)。以红茶、绿茶和乌龙茶为基质,按标准加入法进行回收试验,回收率在72.2%～109%之间,测定值的相对标准偏差(n=6)在0.10%～5.2%之间。     

气相色谱-质谱法测定塑料制品中多环芳烃

将正己烷-二氯甲烷(2+1)混合溶剂加入于塑料样品中,在水浴中于室温下超声萃取30 min,所得溶液在控温30℃的水浴中用旋转蒸发浓缩至2 mL,并将此溶液通过硅胶柱净化分离.先用正己烷淋洗硅胶柱以洗去非极性的正构烷烃,然后以正己烷-二氯甲烷(3+2)混合溶剂淋洗,所得洗脱液先经旋转蒸发浓缩至2 mL,再用氮气吹拂浓缩至恰为1.0 mL,此溶液供气相色谱-质谱分析之用,对相应的分析条件也作了详述.由于采用了先旋转蒸发后氮气吹拂的浓缩方法,不仅使蒸发时间缩短,而且减少了低沸点多环芳烃(PAH)的挥发损失.按所提出的方法测定了塑料中16种PAH,方法的检出限(3S/N)小于0.01 mg·kg-1.选用一种含PAH甚少的塑料样品作为基体,加入3个浓度水平含16种PAH的混合标准溶液按方法操作进行回收试验,测得回收率在87.2%～100.2%之间,测定值的相对标准偏差(n=7)在1.3%～5.8%之间.     

高效液相色谱-质谱联用法测定茶叶中30种磺酰脲类除草剂的残留量

提出了高效液相色谱-质谱联用法测定茶叶中30种磺酰脲类除草剂残留量的方法。样品经少量水浸泡后乙腈提取,经Cleanert HXN固相萃取柱净化,用乙腈与0.02mol·L-1磷酸溶液(按体积比9比1混合)的混合液洗脱,洗脱液经氮气吹干后用1mL流动相溶液溶解残渣,所得溶液供高效液相色谱-质谱分析,用外标法定量。30种磺酰脲类标准品的质量浓度在100μg.L-1以内呈线性,方法的检出限(2S/N)在2～10μg.kg-1之间。平均加标回收率在74.5%～115.5%之间,相对标准偏差(n=6)在1.30%～9.36%之间。     

Multiresidue analysis of 47 pesticides in cooked wheat flour and polished rice by liquid chromatography with tandem mass spectrometry

Liquid chromatography in conjunction with tandem mass spectrometry was used to directly quantify of 47 pesticide residues from cooked wheat flour and polished rice, which are the most widely consumed cereals in the Republic of Korea. The sample clean‐up was carried out according to the method established by the Korea Food and Drug Administration. The mobile phase for liquid chromatograpy separation consisted of water and 5 mm methanolic ammonium formate. Tandem mass spectroscopy experiments were performed in electrospray ionization positive mode and the multiple reaction monitoring mode. The matrix effects estimated for the 47 pesticides had a mean value of 99% and ranged from 45 to 147%. High recoveries (70–140%) and relative standard deviations (≤20%) were achieved for most of the pesticides tested. The method used in this study allowed for rapid quantification and identification of low levels of pesticides in cooked wheat flour and polished rice samples. Of the screened pesticide residues, only tricyclazole and fenobucarb were found in polished rice samples. However, no samples contained residues above the MRL established by the Korea Food and Drug Administration. Copyright © 2008 John Wiley & Sons, Ltd.     

Use of a multifunctional column for the determination of deoxynivalenol in grains, grain products, and processed foods

Deoxynivalenol (DON), also known as vomitoxin, belongs to a class of naturally occurring mycotoxins produced by Fusarium spp. DON, 12, 13-epoxy-3,7 trihydroxytrichothec-9-en-8-one, is one of the most frequently detected mycotoxins in agricultural commodities worldwide. A method consisting of extraction, filtration, column cleanup, and RP-HPLC-UV separation and quantitation was validated for the determination of DON in grains (rice and barley), grain products (whole wheat flour, white flour, wheat germ, and wheat bran), and processed foods (bread, breakfast cereals, and pretzels). A 25 g test portion was extracted with 100 mL acetonitrile-water (84 + 16, v/v). After blending for 3 min, the supernatant was applied to a multifunctional column (MycoSep 225). The purified filtrate (2 mL) was evaporated to dryness and redissolved in the mobile phase. The toxins were then subjected to RP-HPLC-UV analysis. The accuracy and repeatability characteristics of the method were determined. Recoveries of DON added at levels ranging from 0.5 to 1.5 microg/g for all test matrixes were from 75 to 98%. SD and RSD(r) ranged from 0.7 to 11.6% and 0.9 to 12.7%, respectively. Within-laboratory HorRat values were from 0.1 to 0.7 for all matrixes analyzed. The method was found to meet AOAC method performance criteria for grains, grain products, and processed foods. The identity of DON in naturally contaminated test sample extracts was confirmed by HPLC/MS/MS analysis.     

同位素稀释-液相色谱-串联质谱法在小麦粉细交链孢菌酮酸和腾毒素标准物质制备和定值中的应用

建立了小麦粉中细交链孢菌酮酸（TeA）和腾毒素（TEN）标准物质的研制和定值方法,为开展粮食中交链孢霉毒素基体标准物质的研制提供重要方法学借鉴。该标准物质样品为天然污染交链孢霉毒素的小麦籽粒,定值目标物为TeA和TEN,采用同位素稀释-液相色谱-串联质谱法（ID-LC-MS/MS）进行定值测量,多个实验室合作定值。所研制的标准物质具有常温避光保存、定值不确定度小等特点。该标准物质是目前国际上唯一一种天然污染TeA和TEN的小麦粉标准物质,可用于食品安全风险监测、产品质量检测等领域相关分析方法的评价和测量质量控制等。     

23种中国和法国小麦样品及小麦面粉样品中九种元素的分析

采用电感耦合等离子体发射光谱对１０种法国小麦样品,２种中国小麦样品,７种法国小麦面粉样品以及４种中国面粉样品进行了钙,镁,锌,铁,锰,铜,钼,钾及磷共９种微量和常量元素的含量分析。     

A fast and reliable method for the quantitative determination of benzimidazoles and metabolites in milk by LC-MS/MS with on-line sample treatment

A method to detect the presence of common wheat in durum wheat flour samples was developed and tested. Flour samples, or ground wheat samples, were digested by pepsin and chymotrypsin, and the peptide mixture obtained was analyzed by LC/ESI-MS and LC/ESI-MS/MS, which led to the identification of two marker peptides. One peptide was coded only in the DD genome, and thus present only in common wheat; the second was present in all wheat samples (both common and durum), so it was used as marker of the total wheat content. The ratio of the chromatographic areas of these two peptides, as determined by LC/ESI-MS, was related to the proportion of common wheat in the sample using a calibration curve that was constructed with standards of known composition. The proportions of common wheat in samples obtained by mixing different common and durum wheat varieties were accurately determined by this method. Finally, the method was applied in a survey of several durum wheat flour brands present on the Italian market. The results of the survey revealed that contamination of durum wheat flour with common wheat is commonplace.     

Analysis of pesticide residues using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) pesticide multiresidue method in combination with gas and liquid chromatography and tandem mass spectrometric detection

The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 80 pesticides belonging to various chemical classes from various types of representative commodities with low lipid contents. A mixture of 38 pesticides amenable to gas chromatography (GC) were quantitatively recovered from spiked lemon, raisins, wheat flour and cucumber, and determined using gas chromatography-tandem mass spectrometry (GC-MS/MS). An additional mixture of 42 pesticides were recovered from oranges, red wine, red grapes, raisins and wheat flour, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination. The pesticides chosen for this study included many of the most frequently detected ones and/or those that are most often found to violate the maximum residue limit (MRL) in food samples, some compounds that have only recently been introduced, as well as a few other miscellaneous compounds. The method employed involved initial extraction in a water/acetonitrile system, an extraction/partitioning step after the addition of salt, and a cleanup step utilizing dispersive solid-phase extraction (D-SPE); this combination ensured that it was a rapid, simple and cost-effective procedure. The spiking levels for the recovery experiments were 0.005, 0.01, 0.02 and 0.2 mg kg(-1) for GC-MS/MS analyses, and 0.01 and 0.1 mg kg(-1) for LC-MS/MS analyses. Adequate pesticide quantification and identity confirmation were attained, even at the lowest concentration levels, considering the high signal-to-noise ratios, the very good accuracies and precisions, as well as the good matches between the observed ion ratios. Mean recoveries mostly ranged between 70 and 110% (98% on average), and relative standard deviations (RSD) were generally below 10% (4.3% on average). The use of analyte protectants during GC analysis was demonstrated to provide a good alternative to the use of matrix-matched standards to minimize matrix-effect-related errors. Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity/pesticide combinations.     

Multiresidue gas chromatographic method for determining synthetic pyrethroid pesticides in agricultural products: collaborative study

Fourteen laboratories from 6 countries and regions participated in an international collaborative study to evaluate a multiresidue gas chromatographic (GC) method for determining 8 synthetic pyrethroid pesticides in grains, fruits, and vegetables. The study design was based on Youden's matched-pairs principle for collaborative tests of analytical methods. Each laboratory analyzed 12 collaborative samples of wheat, oranges, and tomatoes as blind samples. Wheat samples were extracted with acetonitrile-water (2 + 1), while orange and tomato samples were extracted with acetone. Residues were partitioned into hexane, evaporated to dryness with a rotary evaporator, and then dissolved in hexane. The hexane extract was partitioned with acetonitrile and cleaned up on a 5% water-deactivated Florisil column with 6% ethyl ether in hexane as eluant. Residue concentrations were determined by GC with electron capture detection with splitless injection by comparison with single-point calibration standards. The appropriate standard concentration was determined by screening sample extracts before analysis. The multiresidue method was tested over the concentration range of 0.095-1.909 mg/kg depending on the 8 different of pesticides and agricultural products analyzed in the collaborative study. Statistical analysis of data from 13 laboratories showed weighted average recoveries for 8 pyrethroids in wheat, oranges, and tomatoes at 0.105-1.909, 0.095-1.909, and 0.105-0.954 mg/kg, respectively, ranging from 91.8 to 100.2%, from 88.1 to 100.6%, and from 88.2 to 101.5%, respectively. Reproducibility relative standard deviation values ranged from 6.46 to 17.74%, from 5.94 to 18.13%, and from 5.59 to 10.48%, respectively. Repeatability relative standard deviation values ranged from 6.34 to 10.84%, from 5.19 to 11.72%, and from 3.20 to 8.09%, respectively. The multiresidue GC method for determining synthetic pyrethroid pesticides in agricultural products has been adopted first action by AOAC INTERNATIONAL.     

基于真菌毒素污染差异的液相色谱-串联质谱法鉴别板栗粉中掺假小麦粉

建立了分散固相萃取-超快速液相色谱-串联质谱法同时测定板栗粉和小麦粉中43种真菌毒素的方法,对48份板栗粉和80份小麦粉样品的污染状况进行调查,筛选出5种专属于小麦粉的标志性真菌毒素.样品采用84％(v/v)乙腈水溶液提取,提取液采用C18结合增强型脂质去除净化剂(EMR-Lipid)净化,采用响应曲面-中心组合设计优...     

Measurement of water absorption capacity in wheat flour by a headspace gas chromatographic technique

The purpose of this work is to introduce a new method for quantitatively analyzing water absorption capacity in wheat flour by a headspace gas chromatographic technique. This headspace gas chromatographic technique was based on measuring the water vapor released from a series of wheat flour samples with different contents of water addition. According to the different trends between the vapor and wheat flour phase before and after the water absorption capacity in wheat flour, a turning point (corresponding to water absorption capacity in wheat flour) can be obtained by fitting the data of the water gas chromatography peak area from different wheat flour samples. The data showed that the phase equilibrium in the vial can be achieved in 25 min at desired temperature (35°C). The relative standard deviation of the reaction headspace gas chromatographic technique in water absorption capacity determination was within 3.48%, the relative differences has been determined by comparing the water absorption capacity obtained from this new analytical technique with the data from the reference technique (i.e., the filtration method), which are less than 8.92%. The new headspace gas chromatographic method is automated, accurate and be a reliable tool for quantifying water absorption capacity in wheat flour in both laboratory research and mill applications.     

Suitability of an orbitrap mass spectrometer for the screening of pesticide residues in extracts of fruits and vegetables

For about 500 pesticides, the sensitivity of a benchtop high-resolution mass spectrometer using the Orbitrap for mass separation was compared to that of a widely used (low-resolution) tandem mass spectrometer. Both instruments were coupled to LC and used electrospray ionization. The selectivity of the Orbitrap in the full-scan acquisition mode without fragmentation was evaluated at a resolution of 100 000 full width at half maximum for all pesticides detectable with sufficient sensitivity. For this purpose, quasimolecular ions were extracted within 5 ppm windows from total ion chromatograms of two types of extracts of cucumber, lemon, wheat flour, raisin, and tea. In each of the obtained reconstructed ion chromatograms (individual chromatograms for 500 pesticides, each pesticide in 10 different extracts) the sum of signals not arising from the analyte was used to get a measure on selectivity. In addition, the target analyte list was checked for ions of similar mass. The influence of matrix on the ability to detect low concentrations of fortified pesticides was also studied, with the help of spiked extracts. This part of the survey tested whether analyte peaks were lost because of insufficient mass resolution or an early closing C-Trap (used to control the ion current into the Orbitrap). Finally, the stability of the ion ratio [M+H]+/[M+Na]+ was tested, which may be helpful to confirm the identity of an analyte.