Lipophilic toxin profiles detected in farmed and benthic mussels populations from the most relevant production zones in Southern Chile

Lipophilic toxins associated with diarrhoeic toxins were found in Mytilus chilensis (Blue mussels) and Aulacomya ater (Ribbed mussels). These shellfish samples were collected from Chiloe Island, Southern Chile. The samples were tested by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After the analysis, four toxins were found: DTX-1, DTX-3, YTX and PTX. All toxins were identified by comparing their HPLC retention times with those of analytical standards and confirmed by LC-MS/MS. Dinophysistoxin-1 (DTX-1) and dinophysistoxin-3 (DTX-3) toxins were the major components within the mussel extracts. Nevertheless, the percentages of these toxins differed depending on the area they were collected from and/or the sampling date. The levels detected in Butacheuques Island for okadaic acid (OA) was 267 ± 3.5 μg OA eq kg(-1) (p < 0.05) and for DTX-3 was 183.4 ± 7.5 μg kg(-1) in ribbed mussels. Pectenotoxin (PTX) and yessotoxin (YTX) were the toxins detected in minor proportions in the toxic profile of the bivalves. The maximum concentration of YTX detected in ribbed mussels was 85.2 ± 2.8 μg kg(-1) in Mechuque Island, whereas the PTX-2 level in ribbed mussels was 82.0 ± 2.4 μg kg(-1) in Cailin Island. Analogues of YTX and PTX-2 were not detected in any of the analysed mussels, which did not support the supposed presence of isomers of toxins as a result of the enzymatic metabolism of bivalves. This study found evidence proving co-occurrence of lipophilic toxins - like PTX and YTX - with diarrhoeic toxin in samples collected in Southern Chile, which is, to date, the more complex mix of lipophilic toxins ever found in mussels samples from Southern Chile.     

Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the Southern part of Chile

The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55–2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of bioaccumulation and biotransformation they will thereafter exhibit.     

Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

Until recently, little focus was given to the presence of diarrhetic shellfish poisoning (DSP) toxin esters in seafood products. However, during the last few years, the occurrence of a high percentage of esters of the total amount of DSP toxins present in some seafood products has been observed. Samples of Danish surf clams (Spisola spp.) and blue mussels (Mytilus edulis) from 1999-2004 were analysed by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) for the presence of DSP toxin esters. The samples contained only okadaic acid and esters of okadaic acid. The level of total okadaic acid equivalents ranged from 224 to 2516 µg kg^-1 in surf clams. The percentage of okadaic acid esters of the total okadaic acid equivalents ranged from 83 to 98%, mean 95%. The level of total okadaic acid equivalents ranged from 43 to 1631 µg kg^-1 in blue mussels. The percentage of okadaic acid esters of the total okadaic acid equivalents ranged from 21 to 86%, mean 59%. The probability of a high percentage of okadaic acid esters seems to increase with higher amounts of total okadaic acid equivalents in the bivalves. The large prevalence of DSP toxin esters are of particular importance because of the increased use of chemical methods instead of mouse bioassay for the detection of DSP toxicity.     

免疫亲和净化-液相色谱-串联质谱法测定贝类中腹泻性贝类毒素

建立贝类中腹泻性贝类毒素的免疫亲和净化-液相色谱-串联质谱分析方法。样品采用80%甲醇溶液提取,选择磷酸盐缓冲液与提取液(4∶1,V/V)混合稀释后,免疫亲和选择专一净化,液相色谱-串联质谱分析。根据腹泻性免疫亲和柱的使用特性,对上样液、淋洗液、洗脱液等参数进行优化。质谱采用电喷雾负离子电离,多反应监测模式,外标法定量。3种分析物在1.0~100μg/L质量浓度范围内线性相关系数均大于0.996,对应的检出限和定量限均为0.3μg/kg和1.0μg/kg,平均回收率为82.7%~94.3%,相对标准偏差为0.70%~7.61%。本方法基质干扰小、净化效果强、灵敏度高,适合贝类中腹泻性贝类毒素的分析测定。     

Transfer of aflatoxin B1 and fumonisin B1 from naturally contaminated raw materials to beer during an industrial brewing process

The aim of this research was to determine the fate of aflatoxins (AFs) and fumonisins (FBs) naturally occurring in raw materials (maize grit and malted barley) during four industrial brewing processes. The aflatoxin B₁ (AFB₁) level in raw materials varied from 0.31 to 14.85 µg kg^?1, while the fumonisin B₁ (FB₁) level (only in maize grit) varied from 1146 to 3194 µg kg^?1. The concentration in finished beer ranged from 0.0015 to 0.022 µg l^?1 for AFB₁ and from 37 to 89 µg l^?1 for FB₁; the other aflatoxins and fumonisin B₂ were not found in beer samples. The average percentage of toxins recovered in finished beer, referring to the amounts contained in raw materials, were 1.5% ± 0.8% for AFB₁ and 50.7% ± 4.7% for FB₁. These results were mainly due to the different solubility of the two mycotoxins during the mashing process. If raw materials comply with the limits fixed by European Commission Regulations, the contribution of a moderate daily consumption of beer to AFB₁ and FB₁ intake does not contribute significantly to the exposure of the consumer.     

液相色谱-串联质谱法快速测定食品中的可乐定

目的 采用超高压液相色谱-电喷雾串连四极杆质谱分析食品基质中的可乐定, 为可乐定中毒事件的样本分析提供依据。方法 食物样本粉碎后经甲醇水溶液超声提取, 低温离心后, 上清液用 Waters ACQUITY UPLCTM BEH C18 色谱柱分离, 以 0.1%甲酸和甲醇溶液为流动相梯度洗脱, 最后用串联四极杆质谱在正离子MRM 模式下进行测定。结果 以淀粉和炸鸡为加标基质, 三个加标水平下可乐定的平均回收率为91.5%~127.8%, 相对标准偏差小于 16%, 定量限为 0.02 mg/kg。结论 该方法操作快速简单、重现性好, 成功用于 2010 年 4 月怀柔水岸山吧可乐定中毒事件的食品检测。     

Rapid multi-class multi-residue method for the confirmation of chloramphenicol and eleven nitroimidazoles in milk and honey by liquid chromatography-tandem mass spectrometry (LC-MS)

A confirmatory method was developed to allow for the analysis of eleven nitroimidazoles and also chloramphenicol in milk and honey samples. These compounds are classified as A6 compounds in Annex IV of Council Regulation 2377/90 (European Commission 1990) and therefore prohibited for use in animal husbandry. Milk samples were extracted by acetonitrile with the addition of NaCl; honey samples were first dissolved in water before a similar extraction. Honey extracts underwent a hexane wash to remove impurities. Both milk and honey extracts were evaporated to dryness and reconstituted in initial mobile phase. These were then injected onto a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system and analysed in less than 9 min. The MS/MS was operated in multiple reaction monitoring (MRM) mode with positive and negative electrospray ionization. The method was validated in accordance with Commission Decision 2002/657/EC and is capable of analysing metronidazole, dimetridazole, ronidazole, ipronidazole and there hydroxy metabolites hydroxymetronidazole, 2-hydroxymethyl-1-methyl-5-nitroimidazole, and hydroxyipronidazole. The method can also analyse for carnidazole, ornidazole, ternidazole, tinidazole, and chloramphenicol. A recommended level of 3 µg l^?1/µg kg^?1 for methods for metronidazole, dimetridazole, and ronidazole has been recommended by the Community Reference Laboratory (CRL) responsible for this substance group, and this method can easily detect all nitroimidazoles at this level. A minimum required performance level of 0.3 µg l^?1/µg kg^?1 is in place for chloramphenicol which the method can also easily detect. For nitroimidazoles, the decision limits (CCα) and detection capabilities (CCβ) ranged from 0.41 to 1.55 µg l^?1 and from 0.70 to 2.64 µg l^?1, respectively, in milk; and from 0.38 to 1.16 µg kg^?1 and from 0.66 to 1.98 µg kg^?1, respectively, in honey. For chloramphenicol, the values are 0.07 and 0.11 µg l^?1 in milk and 0.08 and 0.13 µg kg^?1 in honey. Validation criteria of accuracy, precision, repeatability, and reproducibility along with measurement uncertainty were calculated for all analytes in both matrices.     

Detection of dehydroepiandrosterone and androsterone in a traditional Chinese herbal product

Dehydroepiandrosterone (DHEA) and androsterone (ADT) were detected in a traditional Chinese herbal product by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). DHEA and ADT were tentatively identified by comparing their electron ionization (EI) mass spectra with those in the GC-MS Wiley database. A multiple reaction monitoring (MRM) scan was performed in LC-MS/MS to confirm the presence of the DHEA and ADT in the herbal product extract. Both the [M + H]⁺ and the [M + NH₄]⁺ of DHEA and ADT were selected as the precursor ions. DHEA was detected with ion transitions m/z 306.4 → 271.2, 306.4 → 253.3, 289.2 → 270.9, 289.3 → 253.1 while ADT was detected with ion transitions m/z 308.5 → 273.6, 308.5 → 255.3, 291.5 → 273.5, 291.5 → 255.2, which confirmed the presence of the two steroid hormones in the herbal product. Limits of detection (LODs) of 0.2 µg ml^-1 for DHEA and 0.3 µg ml^-1 for ADT were found in methanolic standard solutions when [M + NH₄]⁺ of DHEA and ADT were selected as the precursor ions, which allowed the detection of DHEA and ADT at trace level without time-consuming derivatization.     

Trichothecene and beauvericin mycotoxin production and genetic variability in Fusarium poae isolated from wheat kernels from northern Italy

The importance and widespread incidence of Fusarium poae as a natural contaminant of wheat in different climatic areas warrants investigation into the genetic diversity and toxin profile of a northern Italy population. Eighty-one strains of F. poae isolated from durum wheat kernels, identified by species-specific polymerase chain reaction and translation elongation factor-1α gene sequence analysis, were genetically characterized by the amplified fragment length polymorphism (AFLP) technique and analysed by high-pressure liquid chromatography for their ability to produce the beauvericin (BEA) and trichothecene mycotoxins. A high level of variability was observed by using AFLP analyses, with the lowest level of genetic similarity among the strains being approximately 61%. Most of the strains, 95%, produced BEA at <2655 µg g^?1; 88% produced the trichothecene nivalenol at <865 µg g^?1 and 76% produced the trichothecene fusarenon-X at <167 µg g^?1. These data show that F. poae can produce high amounts of BEA together with trichothecenes, and can represent a high potential mycotoxin risk in Italy for wheat colonized by this species.     

Detection of the hepatotoxic microcystins in 36 kinds of cyanobacteria Spirulina food products in China

Gel filtration chromatography, ultra-filtration, and solid-phase extraction silica gel clean-up were evaluated for their ability to remove microcystins selectively from extracts of cyanobacteria Spirulina samples after using the reversed-phase octadecylsilyl ODS cartridge for subsequent analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The reversed-phase ODS cartridge/silica gel combination were effective and the optimal wash and elution conditions were: H₂O (wash), 20% methanol in water (wash), and 90% methanol in water (elution) for the reversed-phase ODS cartridge, followed by 80% methanol in water elution in the silica gel cartridge. The presence of microcystins in 36 kinds of cyanobacteria Spirulina health food samples obtained from various retail outlets in China were detected by LC-MS/MS, and 34 samples (94%) contained microcystins ranging from 2 to 163 ng g^?1 (mean?=?14?±?27 ng g^?1), which were significantly lower than microcystins present in blue green alga products previously reported. MC-RR?–?which contains two molecules of arginine (R)?–?(in 94.4% samples) was the predominant microcystin, followed by MC-LR?–?where L is leucine?–?(30.6%) and MC-YR?–?where Y is tyrose?–?(27.8%). The possible potential health risks from chronic exposure to microcystins from contaminated cyanobacteria Spirulina health food should not be ignored, even if the toxin concentrations were low. The method presented herein is proposed to detect microcystins present in commercial cyanobacteria Spirulina samples.     

Saxitoxins and okadaic acid group: accumulation and distribution in invertebrate marine vectors from Southern Chile

Harmful algae blooms (HABs) are the main source of marine toxins in the aquatic environment surrounding the austral fjords in Chile. Huichas Island (Aysén) has an history of HABs spanning more than 30 years, but there is limited investigation of the bioaccumulation of marine toxins in the bivalves and gastropods from the Region of Aysén. In this study, bivalves (Mytilus chilenses, Choromytilus chorus, Aulacomya ater, Gari solida, Tagelus dombeii and Venus antiqua) and carnivorous gastropods (Argobuccinum ranelliformes and Concholepas concholepas) were collected from 28 sites. Researchers analysed the accumulation of STX-group toxins using a LC with a derivatisation post column (LC-PCOX), while lipophilic toxins (OA-group, azapiracids, pectenotoxins and yessotoxins) were analysed using LC-MS/MS with electrospray ionisation (+/–) in visceral (hepatopancreas) and non-visceral tissues (mantle, adductor muscle, gills and foot). Levels of STX-group and OA-group toxins varied among individuals from the same site. Among all tissue samples, the highest concentrations of STX-group toxins were noted in the hepatopancreas in V. antiqua (95 ± 0.1 μg STX-eq 100 g^?1), T. dombeii (148 ± 1.4 μg STX-eq 100 g^?1) and G. solida (3232 ± 5.2 μg STX-eq 100 g^?1; p < 0.05); in the adductor muscle in M. chilensis (2495 ± 6.4 μg STX-eq 100 g^?1; p < 0.05) and in the foot in C. concholepas (81 ± 0.7 μg STX-eq 100 g^?1) and T. dombeii (114 ± 1.2 μg STX-eq 100 g^?1). The highest variability of toxins was detected in G. solida, where high levels of carbamate derivatives were identified (GTXs, neoSTX and STX). In addition to the detected hydrophilic toxins, OA-group toxins were detected (OA and DTX-1) with an average ratio of ≈1:1. The highest levels of OA-group toxins were in the foot of C. concholepas, with levels of 400.3 ± 3.6 μg OA eq kg^?1 (p < 0.05) and with a toxic profile composed of 90% OA. A wide range of OA-group toxins was detected in M. chilensis with a toxicity < 80 μg OA eq kg^?1, but with 74% of those toxins detected in the adductor muscle. In all evaluated species, there was no detection of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods. In addition, the STX-group and OA-group toxin concentrations in shellfish was not associated with the presence of HAB. The ranking of toxin concentration in the tissues of most species was: digestive glands > mantle > adductor muscle for the STX-group toxins and foot > digestive gland for the OA-group toxins. These results gave a better understanding of the variability and compartmentalisation of STX-group and OA-group toxins in different bivalve and gastropod species from the south of Chile, and the analyses determined that tissues could play an important role in the biotransformation of STX-group toxins and the retention of OA-group toxins.     

基于动态微波辅助萃取法快速检测西红柿中 六种三嗪类除草剂

目的 建立简便和快速地萃取西红柿中六种三嗪类除草剂的方法。方法 首先, 西红柿中三嗪类除草剂通过动态微波辅助萃取法进行萃取之后, 利用盐析液液萃取法对萃取物进行快速的富集和净化; 之后, 将获得的萃取物用氮气吹干, 用流动相定容至0.5 mL; 最后, 采用高效液相色谱-质谱仪对萃取物进行分析。结果 实验中对影响动态微波辅助萃取和盐析液液萃取萃取效率的实验条件进行了优化, 最优的实验条件为: 萃取剂为70%乙腈-水溶液, 微波萃取功率为350 W, 微波萃取时间为7 min, 萃取剂流速为1.0 mL/min, 萃取液pH值为8, 盐析盐为醋酸铵, 用量为2.0 g。六种三嗪类除草剂在1~1000 ng/mL范围内成线性关系, 相关系数为0.995~0.998; 检出限为0.08~0.33 ng/g; 方法的回收率为68%~104%, 相对标准偏差为5.0%~7.3%。结论 该方法被成功应用于西红柿中三嗪类除草剂的检测, 结果令人满意。     

液相色谱-串联质谱高通量检测酸乳中多种塑料添加剂的迁移量

文章建立了一种液相色谱-串联质谱(Liquid chromatography tandem mass spectrometry,LC-MS/MS)高通量检测酸乳中多种塑料添加剂迁移量的方法.以乙酸乙酯为提取溶剂,超声提取两次,每次10 min,离心分离取上清液,氮吹至近干后用甲醇复溶,过有机滤膜后进LC-MS/MS检测...     

Pyrrolizidine alkaloids in honey: comparison of analytical methods

Pyrrolizidine alkaloids (PAs) are a structurally diverse group of toxicologically relevant secondary plant metabolites. Currently, two analytical methods are used to determine PA content in honey. To achieve reasonably high sensitivity and selectivity, mass spectrometry detection is demanded. One method is an HPLC-ESI-MS-MS approach, the other a sum parameter method utilising HRGC-EI-MS operated in the selected ion monitoring mode (SIM). To date, no fully validated or standardised method exists to measure the PA content in honey. To establish an LC-MS method, several hundred standard pollen analysis results of raw honey were analysed. Possible PA plants were identified and typical commercially available marker PA-N-oxides (PANOs). Three distinct honey sets were analysed with both methods. Set A consisted of pure Echium honey (61–80% Echium pollen). Echium is an attractive bee plant. It is quite common in all temperate zones worldwide and is one of the major reasons for PA contamination in honey. Although only echimidine/echimidine-N-oxide were available as reference for the LC-MS target approach, the results for both analytical techniques matched very well (n?=?8; PA content ranging from 311 to 520?µg?kg^?1). The second batch (B) consisted of a set of randomly picked raw honeys, mostly originating from Eupatorium spp. (0–15%), another common PA plant, usually characterised by the occurrence of lycopsamine-type PA. Again, the results showed good consistency in terms of PA-positive samples and quantification results (n?=?8; ranging from 0 to 625?µg?kg^?1 retronecine equivalents). The last set (C) was obtained by consciously placing beehives in areas with a high abundance of Jacobaea vulgaris (ragwort) from the Veluwe region (the Netherlands). J. vulgaris increasingly invades countrysides in Central Europe, especially areas with reduced farming or sites with natural restorations. Honey from two seasons (2007 and 2008) was sampled. While only trace amounts of ragwort pollen were detected (0–6.3%), in some cases extremely high PA values were detected (n?=?31; ranging from 0 to 13019?µg?kg^?1, average?=?1261 or 76?µg?kg^?1 for GC-MS and LC-MS, respectively). Here the results showed significantly different quantification results. The GC-MS sum parameter showed in average higher values (on average differing by a factor 17). The main reason for the discrepancy is most likely the incomplete coverage of the J. vulgaris PA pattern. Major J. vulgaris PAs like jacobine-type PAs or erucifoline/acetylerucifoline were not available as reference compounds for the LC-MS target approach. Based on the direct comparison, both methods are considered from various perspectives and the respective individual strengths and weaknesses for each method are presented in detail.     

Quantitative determination of mycotoxins in urine by LC-MS/MS

Naturally occurring mycotoxins are responsible for a wide array of adverse health effects. The measurement of urinary mycotoxin levels is a useful means of assessing an individual's exposure, but the development of sensitive and accurate analytical methods for detecting mycotoxins and their metabolites in urine samples is challenging. Urinary mycotoxins are present in low pg ml^–1 concentrations, and the chromatographic identification of their metabolites can be obscured by other endogenous metabolites. We developed an analytical method focused on the selection of two appropriate multiple-reaction monitoring transition for unambiguous identification and quantification of carcinogenic aflatoxin M₁ (AFM₁), ochratoxin A (OTA) and fumonisin B₁, B₂ (FB₁, FB₂) in urine samples from a small volunteer group in a pilot study. AFM₁, OTA, FB₁ and FB₂ were concentrated selectively, interfering substances were removed using an immunoaffinity column (IAC), and mycotoxins were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in combination with a stable-isotope standard-dilution assay (SIDA). The method was sensitive enough to measure mycotoxins and their metabolites at pg ml^–1 levels in urine. The combination of LC-MS/MS and SIDA was critical to distinguishing pseudo-OTα interference from genuine OTα. Twelve urine samples contained OTA ranging from 0.013 to 0.093 ng ml^?1 (mean = 0.031 ng ml^?1). AFM₁ were detected in one sample at a 0.002 ng ml^?1 level, while FB₁ and FB₂ were undetectable in all 12 samples. None of the samples in this pilot study contained a detectable level of OTα, despite the presence of OTA, and this may suggest the need for further epidemiological investigation of OTA exposure in the Korean population.     

Antioxidant capacity of potato chips and snapshot trends in acrylamide content in potato chips and cereals on the Canadian market

The concentration of acrylamide was measured in selected varieties of five brands of potato chips and breakfast cereals over a 5-year period. Most of the products were purchased in one locality in Canada. Samples were analysed by an isotope dilution (¹³C₃) acrylamide method. They were extracted with water, partitioned with dichloromethane, filtered through a 5 kDa centrifuge filter, cleaned-up on HLB Oasis polymeric and Accucat mixed mode anion and cation exchange SPE columns, and analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The acrylamide concentration in potato chips varied from 106 to 4630 ng g^?1, while values in cereals varied from 50 to 347 ng g^?1. Wide variations were observed between brands, within brands over time, and between lots of the same brand. A subset of potato chip samples was analysed for in vitro antioxidant activity. No relationship was found between antioxidative capacity of potato chips and their acrylamide content.     

Routine approach to qualitatively screening 300 pesticides and quantification of those frequently detected in fruit and vegetables using liquid chromatography tandem mass spectrometry (LC-MS/MS)

This paper describes an efficient and effective analytical scheme to first screen for 300 pesticides in fruit and vegetables samples using liquid chromatography tandem mass spectrometry (LC-MS/MS) with a commercially enhanced product ion method. Then presumed positive extracts are analysed using a quantitative and confirmatory LC-MS/MS method optimized for 55 pesticides. A quick, easy, cheap, effective, rugged, and safe (QuEChERS) method with acetate buffering (AOAC Official Method 2007.01) was used for sample preparation, which has been previously shown to yield high-quality results for hundreds of pesticide residues in foods. The advantages and disadvantages of both the qualitative screening and quantitative/confirmatory methods and their combination are critically discussed. No false-negatives for the 55 pesticides occurred above 10 ng g^?1 for extracts analysed by both LC-MS/MS methods, and the no false-positives were encountered from the screening analysis (after analyst review) because all presumptive identifications were confirmed in the second analysis. The monitoring scheme was applied during a one-year period on 200 fruit and vegetable samples from Hungarian markets. No pesticide residues were found in half the samples, and twelve violations of European maximum residue limits were detected.     

超高效液相色谱-串联质谱法测定乳饮料中香兰素的不确定度评定

采用液相色谱-质谱法对乳饮料中香兰素进行不确定度评定.通过整个测定过程建立不确定度测定模型来确定影响不确定度的主要来源,并对各不确定度分量进行合成和扩展,最终建立液相色谱-质谱法测定乳饮料香兰素的不确定度评定方法.结果表明,影响乳饮料中香兰素测定的主要来源为称样量、样品定容、测定浓度、测定重复性和提取回收率,其测定结果...     

Identification of the first fumonisin mycotoxins with three acyl groups by ESI-ITMS and ESI-TOFMS following RP-HPLC separation: palmitoyl,linoleoyl and oleoyl EFB1 fumonisin isomers from a solid culture of Fusarium verticillioides

The aim of this study was to apply RP-HPLC/ESI-ITMS and RP-HPLC/ESI-TOFMS to investigate and characterise six new higher molecular weight fumonisins (three pairs of isomers) extracted from a Fusarium verticillioides-infected solid rice culture. The ITMS and ITMS² spectra clearly indicated the m/z values (960, 984 and 986) of the protonated molecules and the FB₁ toxin-like structures of these compounds, respectively. Moreover, the data evaluation software of the TOFMS equipment unambiguously demonstrated the exact masses of the protonated molecules and the suggested empirical formulae (C₅₀H₈₉NO₁₆, C₅₂H₈₉NO₁₆ and C₅₂H₉₁NO₁₆) of the new fumonisins, with mass accuracy in the range between 0.1 and ?1.1?ppm. Subtraction of the empirical formula of FB₁ toxin (C₃₄H₅₉NO₁₅) from these formulae and correction for the mass of water split-off from the fumonisin molecule during ester formation resulted in the empirical formulae of the fumonisin backbone esterifying agents (fatty acids): C₁₆H₃₂O₂ (palmitic acid, PA), C₁₈H₃₂O₂ (linoleic acid, LA) and C₁₈H₃₄O₂ (oleic acid, OA). We denoted the new compounds as esterified FB₁ (EFB₁) toxins, with the suggested names EFB₁ PA, iso-EFB₁ PA, EFB₁ LA, iso-EFB₁ LA, EFB₁ OA and iso-EFB₁ OA. The total amount of these new compounds comprised 0.1% of the FB₁ concentration, which may be rated as significant when it is considered that these new components are significantly more apolar than earlier-described fumonisins, and their uptake into and toxicity elicited in the various tissues of living organisms may therefore also be significantly different from those of other fumonisins.