Determination of tetrodotoxin in puffer-fish tissues, and in serum and urine of intoxicated humans by liquid chromatography with tandem mass spectrometry

A simple and rapid method was developed for the analysis of tetrodotoxin in puffer-fish tissues, and in serum and urine of humans poisoned after consuming puffer-fish, by means of high-performance liquid chromatography with tandem mass spectrometry (LC/MS/MS). Tetrodotoxin was extracted with 2% acetic acid. The extracted solution from puffer-fish tissues was diluted with water, and the extracted solution from human serum and urine was cleaned up by LC/MS/MS with a methacrylate-styrenedivinylbenzene cartridge. The LC separation was performed on a C18 column (50 mm x 2.1 mm i.d.) using 10 mmol/L IPCC-MS7-methanol (65 : 35) as the mobile phase at a flow rate of 0.2 mL/min. The mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of tetrodotoxin were 79-90% from puffer-fish tissues fortified at 0.1 microg/g and 1 microg/g, and 93-101% from human serum and urine fortified at 0.5 ng/mL and 5 ng/mL. The detection limits of tetrodotoxin were 0.01 microg/g in puffer-fish tissues and 0.1 ng/mL in human serum and urine. Thirty samples of puffer-fish from wholesale markets, and 7 serum and 5 urine samples of humans poisoned after consuming puffer-fish were analyzed by this method. Tetrodotoxin was detected in all puffer-fish tissues, and all serum and urine samples at the levels of 0.04-140 microg/g, 0.9-1.8 ng/mL and 15-150 ng/mL, respectively.     

超高效液相色谱-四极杆飞行时间质谱筛查一起由生物碱引起的食物中毒

目的 采用超高效液相色谱-四极杆飞行时间质谱(UPLC-QTOF MS)技术对1起食物中毒事件的样本进行筛查,为患者救治及做好此类中毒的检测提供策略和依据.方法 患者的呕吐物、洗胃液和食物样本经酸化乙腈提取,C18固相萃取填料净化,利用UPLC-QTOF MS进行非依赖型全信息质谱数据采集,经UNIFI软件进行峰谱识别...     

Determination of nitrofurazone in livestock products and seafoods by liquid chromatography-tandem mass spectrometry

A sensitive and selective method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of nitrofurazone (NFZ) in swine muscle, swine liver, chicken muscle, chicken liver, egg, eel, yellowtail and shrimp has been developed. The drug was extracted with 0.2% metaphosphoric acid-methanol (6 : 4), and the extracts were cleaned up on an Oasis HLB cartridge (200 mg). The extracts were analyzed by LC-MS/MS using electrospray ionizationin the negative ion mode. The LC separation was performed on a Hypersil Gold C18 column (15 cmx2.1 mm i.d.) with a gradient system of 0.01% formic acid-acetonitrile as the mobile phase at a flow rate of 0.2 mL/min. The quantitative and confirmatory determination of NFZ was performed by selected reaction monitoring (SRM). The calibration graph for NFZ was rectilinear from 0.2 to 100 ng/mL with SRM. The recoveries of NFZ from samples fortified at 1 and 10 ng/g were 79.6-106.8%, and quantification limit was 0.2 ng/g for the drug. This is well below the detection limit (1 ng/g) set by the Japanese Food Sanitation Law.     

Determination of free and conjugated forms of bisphenol A in human urine and serum by liquid chromatography-tandem mass spectrometry

Exposure of humans to bisphenol A (BPA), a widely used industrial chemical, is well-known. In humans and animals, conjugation of BPA molecule with glucuronide or sulfate is considered as a mechanism for detoxification. Nevertheless, very few studies have directly measured free, conjugated (e.g., glucuronidated), and substituted (e.g., chlorinated) forms of BPA in human specimens. In this study, free, conjugated (BPA glucuronide or BPAG and BPA disulfate or BPADS), and substituted (chlorinated BPA; mono- [BPAMC], di-[BPADC], and trichloride [BPATrC]) forms of BPA were determined in human urine and serum samples, using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. The instrumental calibration for each of the target compounds ranged from 0.01 to 100 ng/mL and showed excellent linearity (r > 0.99). The limits of quantification (LOQs) were 0.01 ng/mL for free BPA and 0.05 ng/mL for the conjugated and substituted BPA. Respective recoveries of the six target compounds spiked into water blanks and sample matrices (urine and serum), and passed through the entire analytical procedure, were 96 ± 14% and 105 ± 18% (mean ± SD) for urine samples and 87 ± 8% and 80 ± 13% for serum samples. The optimal recoveries of BPAG and BPADS in the analytical procedure indicted that no deconjugation occurred during the SPE procedure. The method was applied to measure six target chemicals in urine and serum samples collected from volunteers in Albany, New York. BPA and its derivatives were found in urine samples at concentrations ranging from < LOQ to a few tens of ng/mL. In serum, free and conjugated BPA were detected at sub ng/mL concentrations, whereas BPA chlorides were not detected. The urine and serum samples were also analyzed by enzymatic deconjugation and liquid-liquid extraction (LLE) for the determination of total BPA, and the results were compared with those measured by the SPE method. To our knowledge, this is the first report on the occurrence of BPAG and BPADS in human serum.     

Determination of mepiquat chloride in grape, wine and juice by liquid chromatography with electrospray tandem mass spectrometry

A simple and rapid method was developed for the analysis of mepiquat chloride in grape, wine and juice by high-performance liquid chromatography with electrospray tandem mass spectrometry (LC/MS/MS). Mepiquat chloride was extracted with water-methanol (1:1). Extracted solution was adjusted to pH 10 with ammonia solution. A part of the extracted solution was cleaned up on a styrenedivinylbenzene (SDVB) cartridge for LC/MS/MS. The LC separation was performed on a C18 column (50 mm x 2 mm i.d.) using 0.1% IPCC-MS7-methanol (60:40) as the mobile phase at a flow rate of 0.2 mL/min. The mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of mepiquat chloride from fresh grape, wine and juice fortified at 5 microg/kg and 50 microg/kg were 84.5-96.1%. The lower limit of quantification was 1 microg/kg. Fourteen fresh grape samples, 14 wines (white), 36 wines (red) and 11 juice samples were analyzed by this method. Mepiquat chloride was detected in 5 fresh grape samples, 3 wines (white) and 1 wine (red) at the level of 12.8-199 microg/kg, 5.7-47.7 microg/kg and 24.1 microg/kg, respectively.     

高效液相色谱-串联质谱法检测鲜冻肉中违禁注水药物

建立鲜冻肉中同时检测阿托品、利多卡因、普鲁卡因、山莨菪碱、东莨菪碱、沙丁胺醇6?种违禁注水药物残留的高效液相色谱-串联质谱法。样品经磷酸盐缓冲液提取,HLB固相萃取小柱净化,采用多反应监测模式检测,外标法定量分析。结果表明：6?种药物在0.25～50?ng/mL范围内线性关系良好,线性相关系数均大于0.99,检出限和定量限分别为0.5?μg/kg和2.0?μg/kg;回收率在78.07%～96.76%之间,精密度的相对标准偏差在0.4%～2.1%之间（n=6）。该方法前处理简单、快速、准确、灵敏,可以满足实际检测分析的需要。     

Determination of sucralose in foods by liquid chromatography/tandem mass spectrometry

A simple method for the determination of sucralose in various foods using liquid chromatography-electrospray ionization tandem mass spectrometry (LC/MS/MS) was developed. Sucralose was extracted with water or methanol, and the extract was cleaned up on a C18 cartridge, and diluted with water for injection into the LC/MS/MS. The LC separation was performed with a reversed-phase gradient on an ODS column, and the mass spectral acquisition was done in the negative ion mode by applying selected reaction monitoring (SRM). The recoveries of sucralose from various kinds of foods fortified at 100 micrograms/g and 5 micrograms/g were 88.1-96.7% and 92.7-98.5%, respectively. The lower limits of quantification were 0.5 microgram/g in beverage, low-malt beer, yogurt and chocolate and 2.5 micrograms/g in other foods. Forty-three commercial foods containing sucralose were analyzed by this method. Sucralose was detected in all samples at levels of 3.8-481 micrograms/g.     

Bisphenol S in urine from the United States and seven Asian countries: occurrence and human exposures

As concern regarding the toxic effects of bisphenol A (BPA) grows, BPA in many consumer products is gradually being replaced with compounds such as bisphenol S (BPS). Nevertheless, data on the occurrence of BPS in human specimens are limited. In this study, 315 urine samples, collected from the general populations in the United States, China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam, were analyzed for the presence of total BPS (free plus conjugated) concentrations by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). BPS was detected in 81% of the urine samples analyzed at concentrations ranging from below the limit of quantitation (LOQ; 0.02 ng/mL) to 21 ng/mL (geometric mean: 0.168 ng/mL). The urinary BPS concentration varied among countries, and the highest geometric mean concentration [1.18 ng/mLor 0.933 μg/g creatinine (Cre)] of BPS was found in urine samples from Japan, followed by the United States (0.299 ng/mL, 0.304 μg/g Cre), China (0.226 ng/mL, 0.223 μg/g Cre), Kuwait (0.172 ng/mL, 0.126 μg/g Cre), and Vietnam (0.160 ng/mL, 0.148 μg/g Cre). Median concentrations of BPS in urine samples from the Asian countries were 1 order of magnitude lower than the median concentrations reported earlier for BPA in the same set of samples, with the exception of samples from Japan. There were no significant differences in BPS concentrations between genders (male versus female), or among age groups (categorized as ≤ 19, 20-29, 30-39, 40-49, and ≥ 50 years), or races (Caucasian versus Asian). The daily intake (EDI) of BPS was estimated on the basis of urinary concentrations using a simple pharmacokinetic approach. The median EDI values of BPS in Japan, China, United States, Kuwait, Vietnam, Malaysia, India, and Korea were 1.67, 0.339, 0.316, 0.292, 0.217, 0.122, 0.084, and 0.023 μg/person, respectively. This is the first study to report the occurrence of BPS in human urine.     

Determination and confirmation of five phenolic antioxidants in foods by LC/MS and GC/MS

Identification and determination of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), nordihydroguaiaretic acid (NDGA), propyl gallate (PG) and tert-butylhydroquinone (TBHQ) by means of LC/MS and GC/MS were examined. These five phenolic antioxidants were detected as their pseudo-molecular ions [M-H]- by LC/MS using a Shim-pack FC-ODS column with drying gas. Moreover, BHA, BHT and TBHQ were detected based on their mass fragment ions by GC/MS. Decomposition of TBHQ, NDGA and PG during analysis could be prevented by the addition of L-ascorbic acid (AsA) to the extraction solvent. All five antioxidants were extracted from nikuman, olive oils, peanut butter, pasta sauce and chewing gum with a mixture of acetonitrile-2-propanol-ethanol (2:1:1) containing 0.1% AsA (AsA mixture), which had been cooled in a freezer and filtered. One part filtrate and 5 parts water were mixed and placed on a Mega-Bond Elut C18 cartridge, except in the case of chewing gum. Lipids in foods were removed on a C18 cartridge by washing with 5 mL of 5% acetic acid, and antioxidants were eluted with 5 mL of AsA mixture. The antioxidants spiked into nikuman, olive oil, peanut butter, pasta sauce and chewing gum were successfully identified and their concentrations determined by LC/MS, and GC/MS with good recoveries.     

LC-MS/MS测定尿液中的11种多环芳烃生物标志物

为评估烟气环境中人体对多环芳烃的暴露状态,考察了固相萃取柱、色谱柱和质谱条件对分析结果的影响,建立了测定尿液中1-羟基萘(1-OHNap)、2-羟基萘(2-OHNap)、1-羟基芘(1-OHPyr)、6-羟基(6-OHChr)、3-羟基芴(3-OHFlu)、1-羟基菲(1-OHPhe)、2-羟基菲(2-OHPhe)、3-羟基菲(3-OHPhe)、4-羟基菲(4-OHPhe)、9-羟基菲(9-OHPhe)、2-羟基芴(2-OHFlu)等11种多环芳烃生物标志物的固相萃取-液相色谱-串联质谱方法(LC-MS/MS)。以1-羟基芘-d9(1-OHPyr-d9)、3-羟基菲-d9(3-OHPhe-d9)和1-羟基萘-d8(1-OHNap-d8)为内标,通过β-葡糖苷酸/芳基硫酸酯酶酶解、Bond Elut C18小柱固相萃取、Agilent ZORBAX Eclipse PAH色谱柱分离和多反应监测模式(MRM)质谱检测了尿液中多环芳烃的羟基代谢物(OHPAHs)。结果表明,OHPAHs的定量限为6~130 pg/mL,r为0.9991~1.0000,加标回收率为72.45%~124.50%,日内精密度为1.49%~7.35%,日间精密度为2.90%~12.00%。该方法适用于尿液中多环芳烃生物标志物的分析。     

Monitoring algal toxins in lake water by liquid chromatography tandem mass spectrometry

Microcystins (MCs) and cylindrospermopsin (CYL) are potent natural toxins produced by cyanobacteria (blue-green algae) that grow worldwide in eutrophic freshwaters and cause animal and human water-based toxicoses. The main purpose of this work has been assessing the contamination levels of some MCs and CYL in eutrophic Italian lake (Albano) water. To do this, we have developed an original analytical method involving MC extraction with a sorbent (Carbograph 4) cartridge. CYL is a highly polar compound that is scarcely retained by any sorbent material. To analyze this toxin, we directly injected 0.5 mL of filtered lake water into the liquid chromatography (LC) column. Analytes were quantified by LC coupled to tandem mass spectrometry in the multireaction monitoring mode. The recovery of five selected MCs added to an analyte free lake water sample at three different concentrations (50, 150, and 500 ng/L) ranged between 93 and 103% with RSD values no larger than 8%. Limits of quantification (LOQ) of the five MCs were within the 2-9 ng/L range, whereas the LOQ of CYL was 300 ng/L. The occurrence and abundance of cyanotoxins in Lake Albano was monitored over four months (Sept-Dec 2004) by analyzing water samples collected monthly at the center of the lake and at different depths (from 0 to -30 m). During survey and with the MS/MS system operating in the parent ion scan mode, we individuated two demethylated forms of MC-RR and one demethylated variety of MC-LR. Demethylated MC-RRs are known to be even more toxic than MC-RR toward zooplanktic grazers. CYL was the most-abundant toxin during the first three monitoring months. To the best of our knowledge, this is the first work reporting concentration levels of CYL in lake water.     

Simultaneous determination of daidzein, equol, genistein and bisphenol A in human urine by a fast and simple method using SPE and GC-MS

Human diet contains weakly estrogenic compounds such as daidzein (DAI) and genistein (GEN), phytoestrogens present in soy and many vegetables as well as bisphenol A (BPA), a contaminant from packing materials and plastic containers for foods and beverages. In light of concerns about hormonally active agents, biomonitoring methods are needed to assess human exposure to such compounds. A method for simultaneous determination of DAI, its metabolite equol (EQ), GEN, and BPA by GC-MS analysis was established, validated and applied to measure concentrations in human urine. Sample preparation involves enzymatic conjugate cleavage, SPE and derivatization by silylation. For GC/MS analysis, deuterated DAI and GEN and( 13)C-BPA are used as internal standards. LOD are 4, 4, 5 and 3 ng/mL urine for DAI, EQ, GEN and BPA, respectively. Interassay variations were 9% for DAI, 15% for EQ, 18% for GEN and 10% for BPA. Simple workup and accuracy of the method are suited for biomonitoring. An analysis of urine samples from 15 adults consuming typical German food revealed dietary exposure to phytoestrogens in all samples: GEN concentrations ranged between 13 and 238 ng/mL, those for DAI ranged from 12 to 356 ng/mL. More than half of the individuals excreted also the more estrogenic metabolite EQ, at levels of 8-128 ng/mL. Higher concentrations (GEN: 820, DAI: 960 and EQ: 1740 ng/mL) were measured in a 24 h urine sample upon ingestion of soy protein (50 g with 12.9 mg DAI and 25.2 mg GEN). Only urine collected after some days on strict phytoestrogen-free diet had undetectable isoflavone levels. BPA was detected in 9 of 15 urine samples ranging from 3 to 11 ng/mL, and at 55 ng/mL in one sample. In conclusion, a reliable method to determine BPA and isoflavones in urine was established and applied in a pilot study: Biomonitoring results show much higher dietary exposure to phytoestrogens than to BPA in German adults.     

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。     

An immunoassay to evaluate human/environmental exposure to the antimicrobial triclocarban

A sensitive, competitive indirect enzyme-linked immunosorbent assay (ELISA) for the detection of the antimicrobial triclocarban (TCC) was developed. The haptens were synthesized by derivatizing the para position of a phenyl moiety of TCC. The rabbit antisera were screened and the combination of antiserum 1648 and a heterologous competitive hapten containing a piperidine was further characterized. The IC(50) and detection range for TCC in buffer were 0.70 and 0.13-3.60 ng/mL, respectively. The assay was selective for TCC, providing only low cross-reactivity to TCC-related compounds and its major metabolites except for the closely related antimicrobial 3-trifluoromethyl-4,4'-dichlorocarbanilide. A liquid-liquid extraction for sample preparation of human body fluids resulted in an assay that measured low part per billion levels of TCC in small volumes of the samples. The limits of quantification of TCC were 5 ng/mL in blood/serum and 10 ng/mL in urine, respectively. TCC in human urine was largely the N- or N'-glucuronide. TCC concentrations of biosolids measured by the ELISA were similar to those determined by LC-MS/MS. This immunoassay can be used as a rapid, inexpensive, and convenient tool to aid researchers monitoring human/environmental exposure to TCC to better understand the health effects.     

Urinary bisphenol A concentrations and their implications for human exposure in several Asian countries

Bisphenol A (BPA) is an industrial chemical used in the manufacture of polycarbonate plastics and epoxy resins. Due to the potential of this compound to disrupt normal endocrinal functions, concerns over human exposure to BPA have been raised. Although several studies have reported human exposure to BPA in Western nations, little is known about exposure in Asian countries. In this study, we determined total urinary BPA concentrations (free plus conjugated) in 296 urine samples (male/female: 153/143) collected from the general population in seven Asian countries, China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam, using high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). On the basis of urinary BPA concentrations, we estimated the total daily intake. The results indicated that BPA was detected in 94.3% of the samples analyzed, at concentrations ranging from <0.1 to 30.1 ng/mL. The geometric mean concentration of BPA for the entire sample set from seven countries was 1.20 ng/mL. The highest concentration of BPA was found in samples from Kuwait (median: 3.05 ng/mL, 2.45 μg/g creatinine), followed by Korea (2.17 ng/mL, 2.40 μg/g), India (1.71 ng/mL, 2.09 μg/g), Vietnam (1.18 ng/mL, 1.15 μg/g), China (1.10 ng/mL, 1.38 μg/g), Malaysia (1.06 ng/mL, 2.31 μg/g), and Japan (0.95 ng/mL, 0.58 μg/g). Among the five age groups studied (≤ 19, 20-29, 30-39, 40-49, and ≥ 50 years), the highest median concentration of BPA was found in urine samples from the age group of ≤ 19 years. There was no significant difference in BPA concentrations between genders (male and female) or domicile of residence (rural and urban). The estimated median daily intakes of BPA for the populations in Kuwait, Korea, India, China, Vietnam, Malaysia, and Japan were 5.19, 3.69, 2.90, 2.13, 2.01, 1.80, and 1.61 μg/day, respectively. The estimated daily intake of BPA in the seven Asian countries was significantly lower than the tolerable daily intake recommended by the U.S. Environmental Protection Agency. This is the first study to document the occurrence of and human exposure to BPA in several Asian countries.     

Simultaneous determination of dichlorvos, trichlorfon and naled in fruits and vegetables by liquid chromatography with tandem mass spectrometry

A method for simultaneous determination of Dichlorvos (DDVP), Trichlorfon (DEP) and Naled (BRP) in fruits and vegetables by liquid chromatography with tandem mass spectrometry (LC/MS/MS) was developed. Pesticides were extracted with ethyl acetate together with phosphoric acid and anhydrous sodium sulfate, followed by an ENVI-Carb cartridge cleanup. Phosphoric acid prevented BRP from being converted to DDVP during extraction of pesticides from the sample. When the sample was dissolved in acetonitrile in a silanized glass vial, BRP and DEP remained intact. Mass spectral acquisition was performed with a TurbolonSpray (ESI) interface in the positive mode by applying multiple reaction monitoring. In LC separation, an ODS column was used with acetic acid-ammonium acetate-methanol as a mobile phase. Recoveries from 8 fruits and vegetables at the fortification level of 0.1 microg/g were 75.0-91.8% for BRP, 70.2-88.9% for DDVP, and 77.3-92.1% for DEP. The detection limits of BRP, DDVP and DEP were 1, 2 and 2 ng/g, respectively.     

超高效液相色谱-四极杆/飞行时间质谱检测猪肉和牛肉中30 种食源性兴奋剂类药物残留

建立猪肉和牛肉中30 种食源性兴奋剂的超高效液相色谱-四极杆/飞行时间质谱的快速筛查和确证方法。样品经37 ℃酶解16 h,体积分数1.0%甲酸-乙腈溶液提取后,经PRiME-HLB通过式固相萃取小柱净化,用Waters XBridge BEH C18柱分离,在飞行时间质谱模式和数据依赖扫描串联质谱模式对目标物进行检测,通过一次数据采集,可同时完成化合物的定性筛查和确证。结果表明：30 种食源性兴奋剂的精确质量数偏差小于5.0×10－6,在0.5～100.0 ng/mL范围内线性良好,相关系数大于0.998 0。检出限范围为0.1～2.0 μg/kg;定量限范围为0.2～4.0 μg/kg。方法回收率范围为77.99%～109.2%,相对标准偏差为0.29%～9.68%（n=6）。该方法有效提高了食源性兴奋剂检测的效率和准确度,具有较强的实用价值。     

Determination of dimetridazole, metronidazole and ronidazole in salmon and honey by liquid chromatography coupled with tandem mass spectrometry

A liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed to determine the residues of dimetridazole (DMZ), metronidazole (MNZ) and ronidazole (RNZ) in salmon and honey. These compounds were extracted with ethyl acetate from samples and cleaned up using a silica solid phase extraction (SPE) cartridge. These compounds were determined by reversed-phase LC using a C18 column with distilled water-methanol as the mobile phase, and MS detection in the positive mode by applying selected reaction monitoring (SRM). DMZ-d(3), MNZ-(13)C(2),(15)N(2) and RNZ-d(3) were used as internal standards. The method was validated in salmon and honey spiked with these compounds at 0.4-2 μg/kg, and average recoveries were in the range of 91.2-107.0%. Repeatability was 1.7-17.1% and intermediate precision was less than 20%. The detection limits of DMZ, MNZ and RNZ in salmon and honey were 0.05-0.2 μg/kg. The method was applied to 3 salmon and 20 honey samples. The concentrations of these compounds in all samples were lower than the detection limits established by the Ministry of Health, Labour and Welfare in Japan.     

2DLC-MS/MS法测定人尿液中多环芳烃暴露生物标志物

为解决分析卷烟烟气多环芳烃(PAHs)暴露的生物标志物——羟基多环芳烃(OHPAHs)时基质干扰较大、前处理复杂等问题,建立了中心切割二维液相色谱-串联质谱(2DLC-MS/MS)同时测定人尿液中10种OHPAHs的方法.尿液样品仅需酶解过滤后直接上机,第一维色谱以水-甲醇体系为流动相,C18色谱柱分离除杂;第二维色谱...     

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.