Validation of a rapid and sensitive routine method for determination of chloramphenicol in honey by LC-MS/MS

Chloramphenicol (CAP) is a broad spectrum antibiotic used in the treatment of human and animal diseases. However, CAP can exhibit toxic effects in certain susceptible individuals, causing bone marrow depression, including fatal aplastic anemia. As this condition is dose-independent, CAP has been banned for use in food-producing animals, including honeybees. In this study, a quick, simple and low-cost routine analytical method was developed for the screening and confirmation of chloramphenicol in honey by LC-MS/MS. Sample clean-up takes only two steps without SPE procedure and with recoveries >97%. Honey samples were selected from several producers in Brazil and diluted in a small amount of water. After fortification and addition of d (s)-chloramphenicol as internal standard, the samples were extracted with ethyl acetate. Complete validation of the method was performed on the basis of EU decision 2002/657. Within-laboratory CV reproducibility at the lowest concentration was <10%. An evaluation of two different methods to calculate the decision limit and detection capability gave 0.08 μg kg(-1) for CCα and 0.12 μg kg(-1) for CCβ.     

超声辅助提取-HPLC-ICP/MS联用分析食品中水溶性铬价态

目的 建立一种超声辅助提取-高效液相色谱分离-电感耦合等离子体质谱仪联用法(HPLC-ICP/MS)测定食品中水溶性铬价态分析方法。方法 样品经EDTA-硝酸铵混合溶液提取后,含蛋白质的样品加入铁氰化钾和乙酸锌溶液沉淀蛋白质,0.45μm微孔滤膜过滤后备用。样品经离子交换柱分离,ICP/MS检测。结果 Cr(III)和Cr(VI)在0.5 ng/mL～50 ng/mL的范围内呈线性关系,大米和鸡蛋样品在0.025mg/kg,0.05mg/kg和2.0mg/kg添加水平下的回收率为62%~117.9%;土豆在0.025mg/kg,0.05mg/kg和1.0mg/kg添加水平下回收率为80.2%~118.2%;牛奶在0.025mg/kg,0.05mg/kg和0.6 mg/kg添加水平下回收率为64.5%~106.5%,日内相对标准偏差小于8%,日间相对标准偏差小于10%;两种价态的铬的检出限均为10 μg/kg。结论 该方法快速、准确、灵敏, 适合用于多种食品中可溶性铬价态分析检测。     

Application of ion-trap LC/MS/MS for determination of acrylamide in processed foods

Ion-trap LC/MS/MS was evaluated for use in the determination of acrylamide (AA) in processed foods. Multiple reaction monitoring (MRM) analysis of a series of AA standard solutions containing deuterium-labeled acrylamide (AA-d3) as an internal standard was performed. A linear relationship between the concentration of AA and the ratio of peak area (AA/AA-d3) in the extracted ion chromatogram (m/z 55, 58 derived from m/z 72, 75, respectively) was obtained over a wide range of 2-20,000 ng/mL. The quantification limit of AA was 2 ng/mL. In analyses of 37 commercial foods, AA was detected in a potato snack at the maximum value of 3,570 ng/g and found in 23 foods prepared or cooked at high temperature. The samples were analyzed in triplicate and the relative standard deviations (RSD) were less than 15% in many processed foods.     

ICP/MS and ICP/AES elemental analysis (38 elements) of edible wild mushrooms growing in Poland

Thirty-eight elements, including toxic cadmium, lead, mercury, silver and thallium, were determined in 18 species of wild edible mushrooms collected from several sites in Pomorskie Voivodeship in northern Poland in 1994. Elements were determined by double focused high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES), after wet digestion of the dried samples with concentrated nitric acid in closed PTFE vessels using a microwave oven. K, P and Mg were present at levels of mg/g dry matter; Na, Zn, Ca, Fe, Cu, Mn, Rb, Ag, Cd, Hg, Pb, Cs, Sr, Al and Si were present at µg/g levels, while Tl, In, Bi, Th, U, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, La, Lu and Ba were present at ng/g levels.     

Simultaneous determination of quinolones in foods by LC/MS/MS

A simple method was developed for the simultaneous determination of seven quinolones (enoxacin, ofloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin and sarafloxacin) in foods using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The seven quinolones were extracted with acetonitrile containing 0.2% formic acid, and the extracted solution was cleaned up on a C18 cartridge. The extract was diluted with 5 mmol/L IPCC-MS3 for injection into the LC-ESI-MS/MS. The LC separation was carried out on an ODS column with gradient elution of 5 mmol/L IPCC-MS3-acetonitrile as the mobile phase. Mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of the seven quinolones were mostly greater than 60% from foods fortified at 10 ng/g. The detection limits in foods were 2 ng/g for enoxacin and ciprofloxacin, and 1 ng/g for the other drugs. Twenty cattle muscle, 7 swine muscle, 9 chicken muscle, 16 milk, 19 prawn and 20 broiled eel samples from retail markets were analyzed by this method. Enrofloxacin and its metabolite ciprofloxacin were detected in 9 broiled eel at the level of trace (tr)-34 ng/g and tr-10 ng/g, respectively.     

Simultaneous determination of pesticides in agricultural products by LC/MS/MS using clean-up with ultrafiltration

A method for simultaneous determination of multiple pesticide residues in agricultural products was developed by using a pretreatment with ultrafiltration, followed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). The pretreatment process (extraction of pesticides from agricultural products with methanol, dilution of the extract with water, and ultrafiltration) gave recoveries in the range of 50-150% for 63 of 83 pesticides spiked at 0.25 microg/ g into 6 agricultural products. The detection limits of pesticides by LC/MS/MS were below 0.0005-0.05 micro/g. This method is useful for screening purposes and for multiresidue analysis of pesticides in agricultural products. Pesticide residues in 50 domestic crops were investigated by this method, and residues of 14 pesticides were detected in 30 crops.     

超声萃取-ICP-OES法快速测定食品中硼砂

建立超声萃取-电感耦合等离子体发射光谱（ICP-OES）法快速测定食品中硼砂含量的方法。食品样品经水超声萃取后,直接采用ICP-OES法测定其中硼元素含量,再换算成硼砂的含量。该法在0.05⁵0mg/L范围内线性良好,相关系数为0.9999,检出限为0.95mg/kg（以硼砂计）,低中高三个不同浓度加标回收率为99.1%¹02.4%,相对标准偏差为0.55%⁰.80%。该方法操作简单,分析快速、灵敏、准确,适用于食品中硼砂含量的测定。      

微波消解-电感耦合等离子体质谱法测定调味品中砷的含量

利用微波消解-电感耦合等离子体质谱法(ICP-MS)测定调味食品中砷的含量.样品经过微波消解,在线加入内标校正基体效应,通过修正方程校正质量数干扰.测定砷元素校正曲线的相关系数0.9999,检出限为0.001mg/kg,样品分析结果的变异系数为1.2%～3.3%(n=6),加标回收率在78.4%～93.1%之间.同时采用国家标准方法氢化物-原子荧光光度法验证了方法的准确度,两种方法结果无显著性差异.实验结果表明,本方法具有简单、快速、检出限低等特点,可用于调味品中砷含量的测定和监控.     

Quantitative determination of fluorotelomer sulfonates in groundwater by LC MS/MS

Aqueous film-forming foams (AFFF) are complex mixtures containing fluorocarbon- and hydrocarbon-based surfactants that are used to fight hydrocarbon-fueled fires. The military is the largest consumer of AFFF in the United States, and fire-training activities conducted at military bases have led to groundwater contamination by unspent fuels and AFFF chemicals. A direct-injection, liquid-chromatography tandem mass spectrometry (LC MS/MS) method was developed to quantify a suite of fluorotelomer sulfonate surfactants in groundwater collected from military bases where fire-training activities were conducted. The 4:2, 6:2, and 8:2 fluorotelomer sulfonates were detected and quantified in groundwater from two of the three military bases. The total fluorotelomer sulfonate concentrations observed at Wurtsmith AFB, MI, and Tyndall AFB, FL, ranged respectively from below quantitation (< or = 0.60) to 182 microg/L and from 1100 to 14,600 microg/L. Analyses of a fluorotelomer-based AFFF concentrate by negative ion fast atom bombardment/mass spectrometry and LC MS/MS analyses indicate that the AFFF concentrate contains only a small amount of fluorotelomer sulfonates and that fluoroalkylthioamido sulfonates are the main anionic fluorosurfactant in the mixtures. More research is needed to determine the fate of fluoroalkylthioamido sulfonates in the environment.     

A multi-residue method for the determination of 90 pesticides in matrices with a high water content by LC-MS/MS without clean-up

A method using QuEChERS extraction and LC-MS/MS in electrospray positive ionisation mode was developed and validated for the analysis of 90 pesticides in a high water content matrix (tomato) in a single chromatographic run. To assess the intra-laboratory reproducibility of the method, validation was conducted on four different days by two different analysts. The validation data was treated using a spreadsheet developed in-house, which sets the most appropriate model for linear fit by determining whether the residuals of the calibration curves are homocedastic or heterocedastic. A statistical test for the significance of regression was also carried out. Calibration was always matrix-matched and the curves were obtained over the range 0.0075-0.10 or 0.020-0.125 mg kg(-1). Identification of analytes was based on retention times and MRM ratios. Recoveries were assessed at four different levels for each analyte and were between 73 and 106%, with relative standard deviations under reproducibility conditions of <20%. The measurement uncertainties of the method for each pesticide analysed were below 50%. Previous validation of the same method, applied to papaya samples and satisfactory results obtained in various proficiency tests with different high water content matrices, demonstrated the applicability of the method to these classes of commodities, without clean-up. The validated method will be applied routinely in the pesticide residues monitoring programme that constitutes the National Residue and Contaminant Control Plan of Brazil.     

气相色谱-串联质谱法同时测定肉制品中氯霉素、甲砜霉素残留

建立了肉制品中氯霉素、甲砜霉素的气相色谱串联质谱检测方法。样品经均质后,用乙酸乙酯提取,正己烷脱脂,弗罗里硅土小柱净化,衍生后用气相色谱串联质谱法检测,内标法定量。优化了二级质谱条件,包括离子对及碰撞电压。该方法检出限为氯霉素(CAP)0.02μg/kg,甲砜霉素(TAP)0.1μg/kg,加标回收率均在86%~97%之间,相对标准偏差(RSD)在3.8%~12.3%之间,在0.1~20 ng/mL范围内都呈现出良好线性关系。     

超声萃取-GC/MS法测定纺织品中邻苯二甲酸酯

以二氯甲烷为萃取溶剂,采用超声萃取-GC/MS法测定纺织品中禁用的6种邻苯二甲酸酯(PAEs)。结果表明,该测试方法对6种邻苯二甲酸酯(DBP、BBP、DEHP、DNOP、DINP和DIDP)的检出限分别为0.03,0.08,0.05,0.04,0.30和0.38 mg/kg。以4种标准贴衬为基布,邻苯二甲酸酯标准品的加标回收率为82.5%~112.1%,RSD均小于10%。该方法简单、快捷、准确可靠,适用于对纺织品中PAEs的测定分析。     

超声辅助萃取-ICP原子发射光谱仪联用同时测定水样中多种金属离子

目的本文优化了超声辅助乳化萃取结合电感耦合等离子体（ICP）原子发射法同时测量水样中镉、钴、镍、锌4种金属离子。方法采用吡咯烷二硫代氨基甲酸铵（APDC）溶液作为螯合剂,超声条件下采用二氯甲烷对重金属螯合物进行萃取。优化了缓冲液的pH值,测定了不同加标浓度下方法的回收率。并对自来水、矿泉水、海水等水样进行了测定。结果该方法对Cd、Co、Ni、Zn 4种金属离子在200 μg/L加标条件下绝对回收率为91.0%~27.0%之间,检出限为Cd为0.81 μg/L,Co为1.03 μg/L,Ni为1.28 μg/L,Zn为0.14 μg/L。结论该方法对实际自来水样具有较好的应用,对镉、钴、镍、锌4种金属离子相对回收率分别为96.4%、77.4%、120.2%和85.6%,所测自来水中镉、钴、镍、锌四种金属含量分别为1 μg/L、0 μg/L、2 μg/L和146 μg/L,均符合国标要求。对矿泉水中镉、钴、镍的相对回收率分别为77.8%,89.9%和74.2%。矿泉水中没有检测到镉、钴两种金属离子,镍含量为1 μg/L。从相对回收率结果来看该方法适合于自来水和矿泉水中部分金属离子的测定,而不适合于对海水中金属离子的测定。     

GC/MS联用快速检测纺织品中禁用偶氮染料

建立了一种纺织品中禁用偶氮染料的气相色谱/质谱(GC/MS)联用快速分析方法.在优化的程序升温色谱条件下,采用HP-5 MS毛细管色谱柱对21种芳香胺进行了检测.结果21种芳香胺得到了较好的分离,回收率为89.3%～93.1%,相对标准偏差(RSD)为6.4%～9.5%,运行时间由44min缩短为25min,提高了检测效率,实现了纺织品中禁用偶氮染料的快速测定.该方法快速,准确,适于大批量样品的分析.     

LC-MS/MS multi-analyte method for mycotoxin determination in food supplements

A multi-analyte method for the liquid chromatography-tandem mass spectrometric determination of mycotoxins in food supplements is presented. The analytes included A and B trichothecenes (nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, neosolaniol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin and T-2 toxin), aflatoxins (aflatoxin-B₁, aflatoxin-B₂, aflatoxin-G₁ and aflatoxin-G₂), Alternaria toxins (alternariol, alternariol methyl ether and altenuene), fumonisins (fumonisin-B₁, fumonisin-B₂ and fumonisin-B₃), ochratoxin A, zearalenone, beauvericin and sterigmatocystin. Optimization of the simultaneous extraction of these toxins and the sample pretreatment procedure, as well as method validation were performed on maca (Lepidium meyenii) food supplements. The results indicated that the solvent mixture ethyl acetate/formic acid (95:5, v/v) was the best compromise for the extraction of the analytes from food supplements. Liquid–liquid partition with n-hexane was applied as partial clean-up step to remove excess of co-extracted non-polar components. Further clean-up was performed on Oasis HLB? cartridges. Samples were analysed using an Acquity UPLC system coupled to a Micromass Quattro Micro triple quadrupole mass spectrometer equipped with an electrospray interface operated in the positive-ion mode. Limits of detection and quantification were in the range of 0.3–30 ng g^?1 and 1–100 ng g^?1, respectively. Recovery yields were above 60% for most of the analytes, except for nivalenol, sterigmatocystine and the fumonisins. The method showed good precision and trueness. Analysis of different food supplements such as soy (Glycine max) isoflavones, St John's wort ( Hypericum perforatum), garlic (Allium sativum), Ginkgo biloba, and black radish (Raphanus niger) demonstrated the general applicability of the method. Due to different matrix effects observed in different food supplement samples, the standard addition approach was applied to perform correct quantitative analysis. In 56 out of 62 samples analysed, none of the 23 mycotoxins investigated was detected. Positive samples contained at least one of the toxins fumonisin-B₁, fumonisin-B₂, fumonisin-B₃ and ochratoxin A.     

Simultaneous determination of 7 kinds of preservatives and saccharin in foods with HPLC, and identification with LC/MS/MS

A simultaneous determination method of saccharin (SA), sorbic acid (SOA), benzoic acid (BA), p-hydroxybenzoic acid ethyl (PHBA-Et), p-hydroxybenzoic acid isopropyl (PHBA-isoPr), p-hydroxybenzoic acid propyl (PHBA-Pr), p-hydroxybenzoic acid isobutyl (PHBA-isoBu) and p-hydroxybenzoic acid butyl (PHBA-Bu) in foods by HPLC was examined. A mixture of acetonitrile-water (1:1) was used to extract these additives from foods excluding liquid foods, while acetonitrile was used to extract them from liquid foods. HPLC was performed using a TSKgel ODS80Ts (4.6 mm i.d. x 150 mm) column with a mobile phase of 0.01% formic acid solution containing 2 mmol/L-di-n-butyl (or amyl) ammonium acetate (A) and acetonitrile (B) under the following conditions: A/B = 8: 2 (0-8 min) --> 6: 4 (15-32 min). Recoveries of these additives spiked in foods were 78-120%. The determination limits were 10 microg/g. As the identification method, examination by liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was used. Unknown compounds were identified by detection of product ions from their precursor ions in the negative mode with multiple reaction monitoring, m/z 182 > 106 for SA, m/z 121 > 77 for BA, m/z 111 > 67 for SOA and m/z 165 > 92 for PHBA-Et. Ratios of intensity of m/z 179 > 137 to m/z 179 > 92 were used for identification of isomers PHBA-isoPr and PHBA-Pr, and the ratios of intensity of m/z 193 > 137 to m/z 193 > 92 were used for isomers PHBA-isoBu and PHBA-Bu, because these isomers have very similar (Received December 12, 2006)     

改进的食品中三聚氰胺的高效液相色谱串联质谱检测法

高效液相色谱串联质谱法是测定三聚氰胺公认的标准方法,具有灵敏度高、精密度好等特点.本研究对国家标准GB/T22388-2008中液相色谱串联质谱法进行了改进,对于液态奶、奶粉和鲜蛋基质,采用50%乙腈水溶液超声提取30min,提取液经过离心处理后,用Agela ASB-C18色谱柱(150×2.1min,5μm)分离,乙腈和10mmol/L乙酸铵作为流动相(5:95),用串联质谱在多反应监测模式下定量检测.方法定量限为0.0lmg/kg,线性范围为0.01～0.5mg/L,相关系数r2>0.999.平均回收率为65%-80%,相对标准偏差为2.159%-6.68%(n=6).     

气—质联用法同时检测高脂食品中14种光引发剂

建立气相色谱-质谱联用仪测定高脂食品中14种光引发剂的方法。将均质后的试样经丙酮-正己烷(体积比2:8) 20℃提取15 min后,振荡离心,上清液采用HLB管进行净化,收集洗脱液,并以PSA萃取管进一步净化。离心后提取上机。当加标水平为0. 000 2~0. 001 0 mg/kg时的回收率为73. 0%~92. 4%,相对标准偏差为4. 1%~8. 9%,检出限为0. 02~0. 20μg/kg。该方法操作快捷,技术参数均满足GB/T 27404—2008附录F中的要求,适用于高脂食品中14种光引发剂的同时分析。