Analytical method for carbamate pesticides in processed foods by LC/MS/MS

A rapid analytical method for the simultaneous determination of carbamate pesticides in processed foods was established by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). The pesticides were extracted from samples with acetonitrile using accelerated solvent extract equipment, except for the fine powder type spices, which were extracted in an ultrasonic bath. The crude extract was cleaned up with a multi-solvent GPC column (Shodex Asahipak GF-310 HQ) using acetonitrile as a mobile phase. The eluent from the column at the retention time between 13 to 18 min was concentrated under nitrogen gas and dissolved in a mixture of acetonitrile-water-0.2 mol/L ammonium formate buffer pH 6.0 (10 : 9 : 1). An aliquot was injected into the LC/MS/MS using electrospray ionization (ESI) with acquisition in the positive mode.The recoveries of 29 kinds of pesticide from dried fruits (raisin, prune and mango) and spices (turmeric, masala, sage, thyme and red pepper) fortified at levels of 0.1 and 0.01 microg/g were mostly in the range of 50 to 150% and those from soybean paste and soy sauce fortified at 0.01 microg/g were 46.9 to 122.6% (C.V. 3.8 to 37.6%), except for 4 kinds of pesticide. The determination limits (S/N> or =10) corresponded to 0.001 to 0.05 mug/g of the pesticides in red pepper.     

An improved LC-MS/MS method for the quantitation of acrylamide in processed foods

An improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of acrylamide in processed foods. The homogenized samples, spiked with ¹³C₃-acrylamide as an internal standard, were extracted with water and centrifuged. D₅-3-chloropropanediol as a recovery standard was added to 1-ml aliquots, and the sample was purified with a C₁₈-cartridge column. The extract was directly analyzed using LC-MS/MS without derivatization. The ion transitions of 72–55 m/z (acrylamide), 75–58 m/z (¹³C₃-acrylamide), and 116–98 m/z (d₅-3-chloropropanediol) were found to be the most reliable for the identification and quantification of acrylamide in multiple reaction monitoring. The limit of quantification for acrylamide, defined as a signal-to-noise ratio of 10:1, was 2 μg/kg. The use of d₅-3-chloropropanediol minimized the effects of variation in the sample matrixes and increased the quality of analysis. This method could be applied to the quantification of acrylamide in processed foods.     

Analysis of acrylamide by LC-MS/MS and GC-MS in processed Japanese foods.

Acrylamide concentrations in processed foods (63 samples covering 31 product types) from Japan were analysed by LC-MS/MS and GC-MS methods. The limit of detection and limit of quantification of acrylamide were 0.2 ng x ml(-1) (6 fmol) and 0.8 ng x ml(-1) (22 fmol), respectively, by LC-MS/MS, and those of 2,3-dibromopropionamide derived from acrylamide were 12 ng x ml(-1) (52 fmol) and 40 ng x ml(-1) (170 fmol), respectively, by GC-MS. Repeatability given as RSD was <5 and <15% for the LC-MS/MS and GC-MS methods, respectively. High correlation (r(2) - 0.946) was observed between values obtained by the two methods. Most potato crisps and whole potato-based fried snacks showed acrylamide concentrations >1000 microg x kg(-1). The concentrations in non-whole potato-based snacks, rice crackers processed by grilling or frying, and candied sweet potatoes were lower compared with those in the potato crisps and the whole potato-based fried snacks. One of the whole potato-based fried snacks, however, showed low acrylamide concentration (<50 microg x kg(-1)) suggesting the formation of acrylamide is strongly influenced by processing conditions. Acrylamide concentrations in instant precooked noodles and won-tons were <100 microg x kg(-1) with only one exception. Roasted barley grains for 'Mugi-cha' tea contained 200-600 microg x kg(-1) acrylamide.     

液相色谱串联质谱法测定食品中红曲色素

采用液相色谱串联质谱法测定了食品中红曲红胺、红曲红素、红曲素、红曲黄素的含量,并选择离子检测进行阳性确证。液体试样用水超声提取,离心定容后,固体和半固体样品采用水溶解定容,提取液再经固相萃取柱净化,样液经洗脱定容后,供液相色谱-质谱/质谱仪测定和确证,外标法定量。该方法的最低检出限、线性范围和方法回收率分别为:1.0 mg/kg、1.0～100.0 mg/kg和89.3%～94.3%。     

Analytical method of hydramethylnon in agricultural products by LC-MS/MS

A simple determination method of hydramethylnon in agricultural products by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The sample was homogenized with phosphoric acid and extracted with acetone. An aliquot of crude extract was re-extracted with hexane and sat. NaCl solution. In the case of tea leaf, solidification processing using ammonium chloride and phosphoric acid was performed before re-extraction with hexane. Clean-up was performed using a silica-gel mini column (500 mg). The LC separation was performed on a C18 column using methanol-water (8 : 2) containing 10 mM ammonium acetate as the mobile phase and MS detection with positive ion electrospray ionization. The calibration curve was linear between 0.002-0.2 μg/mL of hydramethylnon. Recoveries (n=5) of hydromethylnon from 10 kinds of agricultural products fortified at 0.01 μg/g (0.05 μg/g for pineapple) were 82-110%, and their relative standard deviations were 2-12%.     

Simultaneous determination of chloramphenicol and florfenicol in liquid milk, milk powder and bovine muscle by LC-MS/MS

A validated method based on European and Brazilian legislation is reported. It is applicable to the simultaneous determination of chloramphenicol (CAP) and florfenicol (FF) by LC-MS/MS in liquid milk, milk powder and bovine muscle. The chromatographic analysis is completed in 6 min and the extraction procedure is very simple, involving only one step liquid-extraction with ethyl acetate. Where it proved necessary to include clean-up, an efficient and rapid step using C18-dispersive solid was added. Initially, a complete validation was performed with liquid milk matrix; later the scope was extended to the other matrices through extending the inter-day precision (within laboratory reproducibility) RSD values. An internal standard (d(5)-CAP) was employed for quantitative purposes. The method was shown to have good accuracy and precision for determining CAP residues at the level of 0.3-0.6 g kg(-1) and FF residues at the level of 5-15 μg kg(-1).     

高效液相色谱-串联质谱法测定多种食品中7种酚类抗氧化剂和对羟基苯甲酸酯类防腐剂

针对多种食品基质(水果罐头、腌鱼罐头、白酒、果酒、饮料、海鲜酱油、糖果、糕点、调味酱和泡菜),建立了同时测定2,6-二叔丁基-4-甲基苯酚(BHT)、丁基羟基茴香醚(BHA)、特丁基对苯二酚(TBHQ)、对羟基苯甲酸甲酯(MP)、对羟基苯甲酸乙酯(EP)、对羟基苯甲酸丙酯(PP)和对羟基苯甲酸丁酯(BP)残留量的高效液相色谱-质谱联用分析方法。样品经饱和无水Na_2SO_4溶液(用磷酸调p H值至2~3)和乙腈提取各种样品中的待分析物,考察了提取溶剂、净化方式对抗氧化剂和防腐剂萃取量的影响。萃取液经色谱柱Kromasil 100-5(150 mm×2.1 mm×5.0μm)分离,进行MRM多反应监测扫描,外标法定量。结果表明:7种抗氧化剂和防腐剂呈良好的线性关系(r2=0.992 8~0.999 6),方法的测定低限为0.03~0.14 mg/kg,进行低、中、高3个浓度水平的添加实验的平均回收率为85.8%~97.0%,相对标准偏差为1.43%~4.18%(n=10)。该方法准确、灵敏度高,重现性好,适合于多种食品中7种抗氧化剂和防腐剂的检测。     

Simultaneous determination of aflatoxin B1 and M1 in milk,fresh milk and milk powder by LC-MS/MS utilising online turbulent flow chromatography

A novel, fully automated method based on dual-column switching using online turbulent flow chromatography followed by LC-MS/MS was developed for the determination of aflatoxin B₁ and M₁ in milk, fresh milk and milk powder samples. After ultrasound-assisted extraction, samples were directly injected into the chromatographic system and the analytes were concentrated on the clean-up loading column. Through purge switch, analytes were transferred to the analytical column for subsequent detection by mass spectrometry. Different types of TurboFlow^TM columns, transfer flow rates and transfer times were optimised. Method limits of detection obtained for AFB₁ and AFM₁ were 0.05 μg kg^–1, and limits of quantification were 0.1 μg kg^–1. Recoveries of aflatoxin B₁ and M₁ were in range of 81.1–102.1% for all samples. Matrix effects of aflatoxin B₁ and M₁ were in range of 63.1–94.3%. The developed method was successfully used for the analysis of aflatoxin B₁ and M₁ in real samples.     

Determination of acrylamide in processed foods by LC/MS using column switching

An LC/MS method was developed for the determination of acrylamide (AA) in processed or cooked foods. AA was extracted with a mixture of water and acetone from homogenized food samples after the addition of 13C-labeled acrylamide (AA-1-(13)C) as an internal standard. The extract was concentrated, washed with dichloromethane for defatting, and cleaned up on Bond Elut C18, PSA and ACCUCAT cartridge-columns, and then AA was determined by LC/MS in the selected ion recording (SIR) mode. For the LC/MS analysis, four LC columns were connected in-line and the flow of the mobile phase was switched according to a time-program. Monitoring ions for AA were m/z 72 and 55, and those for AA-1-(13)C were m/z 73 and 56. AA and AA-1-(13)C were determined without interference from the matrices in all samples. The recoveries of AA from potato chips, corn snack, pretzel and roasted tea spiked at the level of 500 ng/g of AA were 99.5-101.0% with standard deviations (SD) in the range from 0.3 to 1.6%. The limits of detection and quantification of the developed method were 9 and 30 ng/g for AA in samples, respectively. The method was applied to the analysis of AA in various processed or cooked food samples purchased from retail markets. High levels of AA were found in potato chips and French-fried potato (467-3,544 ng/g). Fried and sugar-coated dough cakes (karinto) contained 374 and 1,895 ng/g. Corn snacks contained 117-535 ng/g of AA. Roasted foods (such as roasted sesame seed, roasted barley (mugi-cha), roasted tea (hoji-cha), coffee beans and curry powder) contained 116-567 ng/g of AA. Foods made from fish, egg and meat contained lower levels of AA than the plant-based foods. Foods containing much water showed a tendency to have low levels of AA compared with dry foods. The proposed method was applicable to the analysis of AA in variety of processed foods.     

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.     

Monitoring of 29 weight loss compounds in foods and dietary supplements by LC-MS/MS

Because of the rapid growth in dietary supplement availability and public concern for weight control, the investigation of foods and various dietary supplements illegally adulterated with weight loss compounds has become increasingly important. A total of 29 weight loss compounds, including sennoside, sibutramine, ephedrine and their analogues, found to be adulterated in foods and dietary supplements were simultaneously examined by LC-MS/MS. The 188 samples were collected between 2009 and 2012 in South Korea, and method validation was performed to determine the adulterants to the weight loss compounds. LODs, LOQs and linearity ranged from 0.03 to 7.5 ng ml^?1, from 0.08 to 30.00 ng ml^?1, and from 0.990 to 0.999, respectively. The results showed that nine weight loss compounds, namely bisacodyl, desmethylsibutramine, didesmethylsibutramine, ephedrine, fluoxetine, pseudoephedrine, sennoside A, sennoside B and sibutramine, were detected in 62 of all collected samples and were found in order of frequency as follows: sibutramine, 25.7%; sennoside A, 22.9%; sennoside B, 20.0%; fluoxetine, 8.6%; desmethylsibutramine, 7.1%; bisacodyl, ephedrine, and pseudoephedrine, 4.3%; and didesmethylsibutramine, 2.9%. Sibutramine, which was the most frequently found adulterant, ranged in levels from 0.03 to 132.40 mg g^?1 (2010), from 0.88 to 76.2 mg g^?1 (2011), and from 0.07 to 0.24 mg g^?1 (2012). Although the concentrations of most compounds ranged widely, some compounds such as bisacodyl and fluoxetine were found at high concentrations in several samples.     

Occurrence of emerging mycotoxins in cereals and cereal-based products from the Korean market using LC-MS/MS

The present study aimed to investigate the occurrence of emerging mycotoxins in cereals (n = 61) and cereal-based products (n = 36) collected from Korean market. First of all, using the quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction method, and ultrahigh-pressure liquid chromatography (UPLC) with triple quadruple tandem mass spectrometry (MS/MS), we developed a simple and fast method for quantitative determination of eight emerging mycotoxins including alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), beauvericin (BEA) and enniatins (ENs; ENA, ENA1, ENB and ENB1). The developed analytical method was validated in parameters of linearity, precision and accuracy. For UPLC-MS/MS analysis, the recoveries of emerging mycotoxins from spiked samples at three concentration levels ranged from 82.7% to 108.8% with RSDs between 0.4% and 14.7%. Analytical methods were applied to determine the contamination of mycotoxins in cereal and cereal-based product samples. Sixty-three of the total 97 samples were contaminated with at least one emerging mycotoxin. The maximum number of emerging mycotoxins observed in a single sample was six out of eight analytes. The highest level of contamination was detected in cereal at 70.9 μg/kg for alternariol monomethyl ether (AME). However, currently there is no international standard for emerging mycotoxins in food. Accordingly, it is necessary to establish a database of emerging mycotoxins contamination through continuous monitoring.     

High-throughput method for the determination of residues of β-lactam antibiotics in bovine milk by LC-MS/MS

This study describes the development and validation procedures for scope extension of a method for the determination of β-lactam antibiotic residues (ampicillin, amoxicillin, penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin, ceftiofur, cefquinome, cefoperazone, cephapirine, cefalexin and cephalonium) in bovine milk. Sample preparation was performed by liquid-liquid extraction (LLE) followed by two clean-up steps, including low temperature purification (LTP) and a solid phase dispersion clean-up. Extracts were analysed using a liquid chromatography-electrospray-tandem mass spectrometry system (LC-ESI-MS/MS). Chromatographic separation was performed in a C18 column, using methanol and water (both with 0.1% of formic acid) as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Main validation parameters such as linearity, limit of detection, decision limit (CCα), detection capability (CCβ), accuracy, and repeatability were determined and were shown to be adequate. The method was applied to real samples (more than 250) and two milk samples had levels above maximum residues limits (MRLs) for cloxacillin – CLX and cefapirin – CFAP.     

Analytical method for fast screening and confirmation of multi-class veterinary drug residues in fish and shrimp by LC-MS/MS

A multi-class, multi-residue analytical method based on LC-MS/MS detection was developed for the screening and confirmation of 28 veterinary drug and metabolite residues in flatfish, shrimp and eel. The chosen veterinary drugs are prohibited or unauthorised compounds in Korea, which were categorised into various chemical classes including nitroimidazoles, benzimidazoles, sulfones, quinolones, macrolides, phenothiazines, pyrethroids and others. To achieve fast and simultaneous extraction of various analytes, a simple and generic liquid extraction procedure using EDTA-ammonium acetate buffer and acetonitrile, without further clean-up steps, was applied to sample preparation. The final extracts were analysed by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The method was validated for each compound in each matrix at three different concentrations (5, 10 and 20 ng g^–1) in accordance with Codex guidelines (CAC/GL 71-2009). For most compounds, the recoveries were in the range of 60–110%, and precision, expressed as the relative standard deviation (RSD), was in the range of 5–15%. The detection capabilities (CCβs) were below or equal to 5 ng g^–1, which indicates that the developed method is sufficient to detect illegal fishery products containing the target compounds above the residue limit (10 ng g^–1) of the new regulatory system (Positive List System – PLS).     

Multiresidue automated turbulent flow online LC-MS/MS method for the determination of antibiotics in milk

A fast and reliable multiresidue method is reported for the identification and quantification of 36 different compounds from seven different classes of antibiotics (aminoglycosides, sulfonamides, macrolides, quinolones, tetracyclines, lincosamides and trimethoprim) in milk. Automated online sample cleanup was applied using turbulent flow chromatography (Transcend TLX system), directly coupled to a mass spectrometer (MS/MS) for sensitive and specific detection. The method involved a simple extraction/protein precipitation using acetonitrile, followed by centrifugation and filtration. After this preliminary step, the extract was injected into the TLX-ESI-MS/MS using optimised turbulent flow and liquid chromatography (LC) conditions. Single-laboratory validation of the method was carried out according to the Directive 2002/657/EC, clearly demonstrating the suitability of this method for quantitative determination of this wide range of antibiotics in milk. A small survey, which covered milk samples of different origin and varied fat content, demonstrated the robustness of this method and its suitability for enforcement purposes.     

Determination of steroid hormones in bovine milk by LC-MS/MS and their levels in Swiss Holstein cow milk

Synthetic and natural steroid hormones have attracted some attention in recent years as endocrine active substances (EAS) that interact or interfere with the endocrine system. Endogenous hormones occur naturally in food of animal origin, among which bovine milk represents an important source. This study was conducted to determine the occurrence of steroid hormones (oestrogens, androgens, progestogens and glucocorticoids) in cow’s milk samples from three farms in Switzerland. An isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of 12 hormones in milk. Some hormonal levels from individual cows showed large variations. The average levels of the hormones analysed (17α-estradiol = 31 ng kg^–1, 17β-estradiol = 6 ng kg^–1, estrone = 159 ng kg^–1, 4-androstenedione = 684 ng kg^–1, progesterone = 15486 ng kg^–1, 17-hydroxyprogesterone = 214 ng kg^–1, cortisone = 112 ng kg^–1, and cortisol = 235 ng kg^–1) were comparable with literature data. Estriol, testosterone and androstenediols were not detected at their respective limit of quantification. No significant differences of hormonal content among milk from cows at different lactation/calving numbers were evidenced, except for progesterone and 4-androstenedione. Due to confounding parameters linked to the physiological stage of the animal, like pregnancy and gestational stage (pregnancy trimester), the causal correlation between the variation of the levels for these two hormones and the lactation/calving number could not be unambiguously demonstrated.     

A new solid phase extraction clean-up method for the determination of 12 type A and B trichothecenes in cereals and cereal-based food by LC-MS/MS

A new reliable and cost-efficient solid phase extraction-based clean-up method for the determination of 12 type A and B trichothecenes [deoxynivalenol (DON), nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, fusarenon-X, T-2 toxin, HT-2 toxin, neosolaniol, monoacetoxy-scirpenol, diacetoxyscirpenol, T-2 triol and T-2 tetraol] in cereals and cereal-based food is presented. Furthermore, the suitability for the simultaneous determination of zearalenone is examined. Toxins were extracted from cereal samples using ACN/water (80/20, v/v), purified by means of a new Bond Elut Mycotoxin column and analyzed via liquid chromatography-electrospray ionization tandem mass spectrometry. Limits of detection were calculated for the matrix wheat and ranged from 0.3 to 5 ng/g, depending on the toxin. Average recovery rates for the tested compounds in seven cereal-based matrices have been determined ranging from 65 to 104%. The relative standard deviations of the complete method ranged from 2.67 (DON, wheat) to 20.0% (T-2 toxin, oats).     

Development and validation of LC-MS/MS method with QuEChERS clean-up for detecting cannabinoids in foods and dietary supplements

ABSTRACT

a rapid and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (THC) using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) clean-up for a variety of foods and dietary supplements (DS). QuEChERS is widely used in extraction or clean-up procedures to eliminate interference of matrices such as sugars, organic acids, lipids, and fatty acids. The samples were categorised into three types, and various pretreatment methods were compared for each type. In all types, the QuEChERS was superior and selected as the final pretreatment method. The optimised method was validated for specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, recovery, precision and accuracy. All of the validation results met the requirements of the international guidelines for all types of samples. The validated method was applied to 30 commercial food samples, CBD was detected in 17 samples, with 2 of them detected below the LOQ level and the rest detected in a range of 70 μg/kg to 31305 mg/kg (3.1%, w/w). Meanwhile, THC was detected in 14 samples; 2 of them were detected below the LOQ level and the rest detected in a 0.08–98.62 μg/g range. These results indicated that the validated method can be successfully applied for the determination of cannabinoids in a variety of samples. Furthermore, it will be useful for controlling the illegal distribution of cannabinoids.     

液相色谱串联质谱法测定纺织品和皮革中PFOS含量

针对国外对全氟辛烷磺酸(PFOS)的限量要求,建立了纺织品和皮革中PFOS的检测方法.样品使用甲醇快速提取(用ASE300快速溶剂萃取仪提取),提取液经C18固相萃取柱净化,浓缩定容后供液相色谱串联质谱仪(LC-MS/MS)测定,采用多反应监测(MRM)进行确证,外标法定量.本方法的最低检出限是0.10 mg/kg,线性范围为0.1～60.0 ng.方法回收率在80.0%～105.8%.     

Rapid and sensitive method for the determination of four EU marker polycyclic aromatic hydrocarbons in cereal-based foods using isotope-dilution GC/MS

A rapid and sensitive method has been developed for the determination of the four European Union marker polycyclic aromatic hydrocarbons (PAHs; benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene) in some cereal-based foods. The method is based on pressurised liquid extraction (PLE), solid-phase extraction clean-up (SPE) and isotope-dilution gas chromatography with mass-spectrometric detection (GC/MS). The developed method was calibrated for the content range of 0.05–12.5 µg kg^?1 (expressed on a product basis). Recoveries of PAH were monitored in each sample via the recovery of ¹³C-labelled PAHs. Recovery values were in the range between 86% and 91%, with relative standard deviations (RSDs) between 5% and 9%. The achieved limits of detection for all analytes were below 0.05 µg kg^?1. The applicability of the method for the analysis of routine samples was studied by the analysis of a set of commercial bread and breakfast cereal samples. In all analysed samples, benzo[a]pyrene (BAP) was the most prevalent PAH with the content between 0.09 and 0.30 µg kg^?1. On average, samples showed low levels of the sum of the four EU marker PAHs (ΣPAH4) that ranged between 0.11 and 0.22 µg kg^?1 for bread samples and between 0.23 and 0.87 µg kg^?1 for breakfast cereal samples. The developed method was found suitable for the determination of PAHs in cereal-based foods like cornflakes and breads with total relative fat contents below 3.5%.