Acrylamide levels in Finnish foodstuffs analysed with liquid chromatography tandem mass spectrometry

Sample clean-up and HPLC with tandem mass spectrometric detection (LC-MS/MS) was validated for the routine analysis of acrylamide in various foodstuffs. The method used proved to be reliable and the detection limit for routine monitoring was sensitive enough for foods and drinks (38 microg/kg for foods and 5 microg/L for drinks). The RSDs for repeatability and day-to-day variation were below 15% in all food matrices. Two hundred and one samples which included more than 30 different types of food and foods manufactured and prepared in various ways were analysed. The main types of food analysed were potato and cereal-based foods, processed foods (pizza, minced beef meat, meat balls, chicken nuggets, potato-ham casserole and fried bacon) and coffee. Acrylamide was detected at levels, ranging from nondetectable to 1480 microg/kg level in solid food, with crisp bread exhibiting the highest levels. In drinks, the highest value (29 microg/L) was found in regular coffee drinks.     

液相色谱-串联质谱法测定猪肉及组织中沙丁胺醇的含量不确定度评定

目的分析液相色谱一串联质谱法检测猪肉及组织中沙丁胺醇的不确定度,探讨各因素对检验结果的影响。方法依据JJG1059.1-2012《测量不确定度评定与表示》和CNAS-GL06《化学分析中不确定度的评估指南》规定的方法和程序,分析影响测量不确定的来源,并对各不确定度分量进行了评估。结果合成各变量的不确定度,最终得到测定结果的扩展不确定度:(11.05±0.77)μg/kg(k=2)。结论影响检测结果不确定度的主要因素为回收率和标准曲线拟合,在实际测量过程严格控制实验条件可提高检测的准确性和可靠性。     

Multi-residue method for the analysis of pesticides in Arabica coffee using liquid chromatography/tandem mass spectrometry

Coffee is a major tropical agricultural commodity and represents a significant fraction of the economy of many countries. However, certain plant and animal species can damage coffee crops, affecting trade. A solution to this issue is the use of pesticides, some of which are harmful to human health and the environment. This work consisted of the development of a multi-residue method for the analysis of pesticides in coffee by using LC-MS/MS. The QuEChERS extraction procedure was used. The following analytical parameters were optimised: selectivity, analytical range, linearity, LOD, LOQ, precision (RSD%) and recovery of the method. The results showed that the method is selective, as they were linear in the range of 10.0–100.0 µg kg^?1. The sensitivity, recovery and precision were adequate for the multi-residue analysis of pesticides in coffee. The method was applied to the analyses of 15 Brazilian coffee samples.     

Quantitative analysis of acrylamide in tea by liquid chromatography coupled with electrospray ionization tandem mass spectrometry

An effective sample preparation procedure was optimized and a liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed for the quantitative analysis of acrylamide in tea. [¹³C₃]-acrylamide was used as internal standard. Acrylamide was extracted at 25 °C for 20 min by 10 ml water followed by 10 ml acetonitrile, and then 4 g of magnesium sulfate and 0.5 g of sodium chloride were added to the above mixture under stirring thoroughly. In order to increase the response of acrylamide, 9 ml acetonitrile layer was taken and concentrated to 0.5 ml. Solid-phase extraction with an Oasis MCX cartridge was carried out for clean-up. The limit of detection (LOD) and limit of quantification (LOQ) were 1 and 5 ng/ml, respectively. The recovery efficiency of the extraction procedure ranged between 74% and 79%. The levels of acrylamide in 30 tea samples were less than 100 ng/g. Black, oolong, white and yellow tea samples had quite low acrylamide contents (<20 ng/g). Higher acrylamide levels occurred in baked, roasted, and one sun-dried green tea samples (46–94 ng/g).     

水果中噻虫嗪农药残留LC/MS/MS测定

目的建立一种简单、快速、灵敏的水果中噻虫嗪农药残留的液相色谱-串联质谱(liquid chromatography-mass spectrometry/mass spectrometry,LC-MS/MS)分析方法。方法称取水果样品5 g,加入乙腈20 m L在超声波振荡条件下提取,提取液使用20 mg石墨化炭黑(Carb)和60 mg N-丙基乙二胺(PSA)粉末进行分散固相萃取净化,经液相色谱质谱联用仪检测,外标法定量。结果噻虫嗪农药残留的色谱图分离效果良好,方法的检出限为0.3μg/kg,线性相关系数为0.9999,噻虫嗪在苹果、梨、桃中的添加水平为0.01、0.05、0.10 mg/kg,回收试验表明该方法平均回收率为88.9%~100.3%(n=6),相对标准偏差为1.98%~4.53%。结论该方法简单、快速、灵敏、净化效果好、回收率高,适合水果中噻虫嗪农药残留的检测和安全监控。     

Validation of antibiotics in catfish by on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry

For the first time automated on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of 13 antibiotics (sulfonamides and tetracyclines) in catfish. The method proposed was validated according to Commission Decision 2002/657/EC, showing good linearity between 2 and 350 μg kg⁻¹, high recovery (80–99%) and reproducibility (13–20%) values, lower detection limits than 0.1 μg kg⁻¹, and quantification limits under 2.4 μg kg⁻¹ (between 39 and 84 times lower than the MRL fixed by the EU). Moreover, the proposed method was also used to determine sulfonamides and tetracyclines in 16 out of 107 samples, all previously analysed by microbiological screening that gave positive results. Five out of 13 antibiotics were found, having tetracycline the higher occurrence (10 samples); in all cases the concentrations were lower than the MRL established.     

Comprehensive screening of veterinary drugs in honey by ultra-high-performance liquid chromatography coupled to mass spectrometry

In the context of multi-residue screening in honey, a complete methodology was developed for 200 veterinary drugs comprising a sample preparation step and an ultra-high-performance liquid chromatography (UHPLC) coupled to time-of-flight (TOF) mass spectrometry analysis. In addition, specific analytical strategies were developed for two compounds, streptomycin and chloramphenicol, using UHPLC and tandem mass spectrometry (MS/MS). Methodologies were then applied to real honey samples obtained from the Swiss market.     

Triacylglycerol analysis of pequi (Caryocar brasiliensis Camb.) oil by electrospray and tandem mass spectrometry

Electrospray ionization liquid chromatography/tandem mass spectrometry was used to identify the fatty acid and triacylglycerol (TAG) composition of pequi (Caryocar brasiliensis Camb.) oil. The fatty acid composition was relatively simple; the oil contained approximately 442 and 517 g kg^?1 of palmitic and oleic acids respectively. Linoleic and stearic acids were found in much smaller amounts. The TAG composition of pequi oil is also relatively simple with trioleoyl glycerol (OOO, 56 g kg^?1), palmitoyl dioleoyl glycerol (POO, 466 g kg^?1) and dipalmitoyl oleoyl glycerol (POP, 452 g kg^?1) comprising 974 g kg^?1 of the total. Dioleoyl stearoyl glycerol (OOS) was found in small amounts (5.2 g kg^?1). All TAGs were identified via sodium adduct molecular ions [M + Na]⁺, where M is the TAG in question. Tandem mass analysis provided a very useful fragmentation pattern showing both sodium adduct diacylglycerol ions and diacylglycerol ions with the neutral loss of fatty acid residues. Copyright © 2005 Society of Chemical Industry     

Determination of malachite green residues in rainbow trout muscle with liquid chromatography and liquid chromatography coupled with tandem mass spectrometry

A method for the determination of malachite green and its major metabolite leucomalachite green in rainbow trout muscle is reported with limits of detection of 0.8 and 0.6 μg kg^-1, respectively. Residues were extracted with an acetonitrile-acetate buffer mixture and partitioned into methylene chloride. Clean-up of the extracts was performed on alumina and propylsulfonic acid solid-phase extraction columns using the automated solid-phase extraction system. The chromatographic separation of malachite green and leucomalachite green was achieved on a Chromspher 5B column using an acetonitrile-acetate buffer mobile phase. Leucomalachite green was converted to malachite green by post-column oxidation before spectrophotometric detection at 600 nm. The mean recoveries of malachite green and leucomalachite green from control rainbow trout muscle spiked at 2-50 μg kg^-1 were 65% (range 63.4-65.9%, relative standard deviation 3.9-16.1%) and 74% (range 58.3-82.6%, relative standard deviation 3.3-11.4%), respectively. Qualitative confirmation of the determined residues was performed with liquid chromatography coupled with tandem mass spectrometry detection with limits of detection of 2.5 and 1 μg kg^-1 for malachite green and leucomalachite green, respectively.     

Assessment of liquid chromatography–tandem mass spectrometry approaches for the analysis of ceftiofur metabolites in poultry muscle

The use of cephalosporin antibiotics in veterinary practice is likely to play an important role in the development of β-lactam-resistant bacteria. To detect off-label cephalosporin antibiotic usage, an analytical method is needed that, besides the native compound, also detects their active metabolites. In this paper, the applicability of three approaches for the quantitative analysis of ceftiofur using LC–MS/MS is assessed, viz. (A) analysis of ceftiofur, desfuroylceftiofur and/or desfuroylceftiofur cystein disulfide, (B) derivatisation of ceftiofur metabolites to desfuroylceftiofur acetamide and (C) chemical hydrolysis using ammonia, to produce a marker compound for ceftiofur. We found that approach A was not suited for quantitative analysis of total ceftiofur concentration or for effectively detecting off-label use of ceftiofur. Approach B resulted in adequate quantitative results, but was considered a single compound method because it depends on cleavage of a thioester group, which is present in only a limited number of cephalosporin antibiotics. Approach C showed adequate quantitative results but, in contrast to approach B, it is applicable to a range of cephalosporin antibiotics. Therefore, it is applicable as a broad quantitative screening of cephalosporin compounds in poultry tissue samples to indicate off-label use of cephalosporins in poultry breeding. Based on this study, it was concluded that approach C is the most suitable to detect off-label use of a range of cephalosporin antibiotics.     

Determination of selected mycotoxins in mould cheeses with liquid chromatography coupled to tandem with mass spectrometry

A simple and feasible method is described for analysing nine mycotoxins in cheese matrix. The method involves liquid extraction followed by high performance liquid chromatographic separation and mass spectrometric detection of the analytes, and allows the determination of aflatoxins B1, B2, G1, G2 and M1, ochratoxin A, mycophenolic acid, penicillic acid and roquefortine C simultaneously. Average recoveries of the mycotoxins from spiked samples at concentration levels of 5-200 µg kg^-1 ranged from 96-143%. Within-day relative standard deviations at these concentration levels varied from 2.3-12.1%. The limit of quantification for aflatoxin M1 was 0.6 µg kg^-1 and for the other compounds 5 µg kg^-1. The method developed was applied for analysing these mycotoxins in blue and white mould cheeses purchased from Finnish supermarkets. Roquefortine C was detected in all of the blue mould cheese samples in concentrations of 0.8-12 mg kg^-1. One blue cheese contained also 0.3 mg kg^-1 mycophenolic acid. The other investigated mycotoxins were absent in the samples.     

Determination of phenolic and other polar compounds in flaxseed oil using liquid chromatography coupled with time-of-flight mass spectrometry

A new method based on high-performance liquid chromatography coupled with electrospray ionisation time-of-flight-mass spectrometry (HPLC–ESI–TOF (MS)) has been used to analyse phenolic compounds in flaxseed oil. Some phenolic compounds such as secoisolariciresnol, ferulic acid and its methyl ester, coumaric acid methyl ester, diphyllin, pinoresinol, matairesinol, p-hydroxybenzoic acid, vanillin and vanillic acid have been detected from flaxseed oil. The quantification of these compounds in three varieties of flaxseed oils was carried out using their commercial standards. The efficiency, rapidity and high resolution of HPLC coupled to the sensitivity, selectivity, mass accuracy and true isotopic pattern from TOF (MS) have revealed an enormous separation potential allowing the determination of a broad series of phenolic and other polar compounds present in flaxseed oil for the first time.     

液相色谱法及液相色谱-串联质谱法测定山楂及其制品中展青霉素的结果比较与建议

目的比较液相色谱法(liquidchromatography,LC)和液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)测定山楂及其制品中展青霉素的方法学指标。方法 LC法:山楂及固体制品经粉碎酶解后,用乙酸乙酯提取,Mycosep?228Aflapat净化柱净化浓缩,以乙腈和水作为流动相进行梯度洗脱,液相色谱仪被测定; LC-MS/MS法:样品处理方法同LC法(除加同位素外),以乙腈和水作为流动相进行梯度洗脱,外标法定量,采用电喷雾离子源负模式测定。结果 LC法和LC-MS/MS法展青霉素在10～200 ng/mL浓度内线性良好,相关系数均大于0.9999; LC法的回收率为96.12%～104.20%, RSD均小于2.5%,检出限为0.52～0.63μg/kg,定量限为1.7～2.0μg/kg; LC-MS/MS法的回收率为94.68%～103.59%, RSD均小于2.5%,检出限为0.12～0.39μg/kg,定量限为0.38～1.29μg/kg。结论 2种方法结果无显著差异,均可适用于山楂及山楂制品中展青霉素的测定。     

Determination of mycotoxins in cereals by liquid chromatography tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC–MS/MS) method is described for simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T2 and HT2-toxin in cereals. One-step extraction using solvent mixtures of acetonitrile:water:acetic acid (79:20:1) without any clean-up was employed for extraction of these mycotoxins from cereals. The mean recoveries of mycotoxins in spiked cereals ranged from 76.8% to 108.4%. Limits of detection (LOD) and quantification (LOQ) ranged 0.01–20 and 0.02–40 ng/g, respectively. The developed method has been applied for the determination of mycotoxins in 100 cereal samples collected from Malaysian markets. A total of 77 cereal samples (77%) contaminated with at least one of these mycotoxins. Occurrence of mycotoxins in commercial cereal samples were 70%, 40%, 25%, 36%, 19%, 13%, 16, and 16% for aflatoxins, OTA, ZEA, DON, FB₁, FB₂, T2 and HT2-toxin, respectively. The results demonstrated that the procedure was suitable for the determination of mycotoxins in cereals and could be implemented for the routine analysis.     

Determination of tertiary butylhydroquinone in edible vegetable oil by liquid chromatography/ion trap mass spectrometry

A simple, sensitive and accurate analytical method for quantification of tertiary butylhydroquinone (TBHQ) in edible vegetable oil was established by liquid chromatography/ion trap mass spectrometry (LC/ITMS). After extraction, 5 μl of the extracts was directly injected into LC/ITMS for TBHQ determination. Ethanol was selected as the extraction solvent. The optimized fragmentation amplitude was 1.70 V and electrospray ionization (ESI) was more suitable than atmospheric pressure chemical ionization (APCI) for TBHQ detection. The calibration curve showed good linearity (R² = 0.9990) and recoveries from spiked samples ranged from 81.9% to 110.5%. Relative standard deviations of intra-day and inter-day were in the ranges 2.5–5.7% and 3.9–13.8%, respectively. The procedure allows the detection of 0.3 mg/kg TBHQ in edible vegetable oil. Typical edible vegetable oils in the market were detected for TBHQ by the proposed method. As results, TBHQ was detected in blend oil, soybean salad oil and camellia oil samples.     

Determination of diquat and paraquat in olive oil by ion-pair liquid chromatography–electrospray ionization mass spectrometry (MRM)

For the first time a method for determination of herbicides diquat (DQ) and paraquat (PQ) in olive oil was developed utilising liquid chromatography–electrospray ionization mass spectrometry (MRM). n-Hexane/10 mM HFBA aqueous solution partitioning was used as the extraction method. Separation was carried out in an Xterra C8 column (100 × 21 mm, 3 μm), using the gradient mode. Solvent A was a HFBA aqueous solution (5 mM, pH 2) and solvent B acetonitrile/methanol 75/25 (v/v). Peaks used for quantification were m/z = 157 (diquat) and m/z = 158 (paraquat). Detection limit found for both diquat and paraquat was 4 μg kg⁻¹. The method can also be applied for determination of chlormequat (CQ, quantification peak m/z = 58), the detection limit being 0.3 μg kg⁻¹. Such limits are clearly lower than the MCLs commonly applied to olive oil as reference criteria (5 times MCLs in olives). Good reproducibilities (day to day and run to run) were obtained.     

Multitoxin evaluation in fermented beverages and cork stoppers by liquid chromatography–tandem mass spectrometry

A total of twenty‐eight mycotoxins were surveyed in wine (red, white and rose), cider (white and rose) and their cork stoppers from eight countries. Toxins of different fungi genera were detected as follows: Alternaria (ATs: alternariol – AOH; alternariol methyl – AME) and Penicillium/Aspergillus (ochratoxin A – OTA; penicillic acid – PAC). Toxins and levels varied with the sample types and country of origin. Wine presented contamination of OTA, AOH and AME. OTA was detected in forty‐one wine samples with levels ranging from 0.01 to 0.86 μg L^?1, below EU legislation. AOH and AME were detected in thirty‐three and eight of wines samples, respectively, at levels from 0.2 to 13.3 μg L^?1, while no contamination was detected in ciders up to the method LOQs. Regarding the cork stoppers toxins detected, they were AOH, AME and PAC. Corks of red wine from different countries had levels of OAH and AME ranging from 5.0 to 101.0 and 2.5 to 5 μg g^?1, respectively. It is necessary to pay more attention on the corks processing and cork type used in the bottles as, different from the ordinary ones, the ground bark and compressed type did not have toxins detected.     

Development and validation of rapid multiresidue and multi-class analysis for antibiotics and anthelmintics in feed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry

A new multi-residue method for the analysis of veterinary drugs, namely amoxicillin, chlortetracycline, colistins A and B, doxycycline, fenbendazole, flubendazole, ivermectin, lincomycin, oxytetracycline, sulfadiazine, tiamulin, tilmicosin and trimethoprim, was developed and validated for feed. After acidic extraction, the samples were centrifuged, purified by SPE and analysed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. Quantitative validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/CE. Matrix-matched calibration with internal standards was used to reduce matrix effects. The target level was set at the authorised carryover level (1%) and validation levels were set at 0.5%, 1% and 1.5%. Method performances were evaluated by the following parameters: linearity (0.986 < R² < 0.999), precision (repeatability < 12.4% and reproducibility < 14.0%), accuracy (89% < recovery < 107%), sensitivity, decision limit (CCα), detection capability (CCβ), selectivity and expanded measurement uncertainty (k = 2).This method has been used successfully for three years for routine monitoring of antibiotic residues in feeds during which period 20% of samples were found to exceed the 1% authorised carryover limit and were deemed non-compliant.