A new on-line solid phase extraction high performance liquid chromatography tandem mass spectrometry method to study the sun light photodegradation of mono-chloroanilines in river water

The study investigates the natural photodegradation pathway of mono-chloroanilines in river waters, with the aim to identify the predominant photoproducts formed. At this purpose a new sensitive on-line SPE HPLC–MS/MS method has been developed with LOQ values equal or lower than the legal threshold concentration levels allowed for mono-chloroanilines in waters. The degradation processes of o-, m- and p-chloroaniline have been investigated subjecting their solutions, prepared both in ultrapure and in river water, to sun light irradiation simulated by a solar box system. The SPE HPLC–MS/MS methodology allowed to evaluate the degradation kinetics, to identify the predominant photodegradation products and to propose the chemical structures. Two photoproducts (aniline and 3-aminophenol), for which standards are available, have also been quantified.     

Simple, high throughput ultra-high performance liquid chromatography/tandem mass spectrometry trace analysis of perfluorinated alkylated substances in food of animal origin: milk and fish

The present study documents development and validation of a novel approach for determination of 23 perfluorinated alkylated substances (PFASs) in food of animal origin represented by milk and fish. The list of target analytes comprises four classes of PFASs, both ionic and non-ionic: 11 perfluorocarboxylic acids (PFCAs), 4 perfluorosulphonic acids (PFSAs), 5 perfluorosulphonamides (FOSAs) and 3 perfluorophosphonic acids (PFPAs). Fast sample preparation procedure is based on an extraction of target analytes with acetonitrile (MeCN) and their transfer (supported by inorganic salts and acidification) into the organic phase. Removing of matrix co-extracts by a simple dispersive solid phase extraction (SPE) employing ENVI-Carb and C18 sorbents is followed by an efficient sample pre-concentration performed by acetonitrile evaporation and subsequent dilution of residue in a small volume of methanol (matrix equivalent in the final extracts was 16 and 8 g mL(-1), for milk and fish respectively). Using modern instrumentation consisting of ultra-high performance liquid chromatography (UHPLC) hyphenated with a tandem mass spectrometer (MS/MS), limits of quantification (LOQs) as low as 0.001-0.006 μg kg(-1) for milk and 0.002-0.013 μg kg(-1) for fish can be achieved. Under these conditions, a wide spectrum of PFASs, including minor representatives, can be determined which enables collecting data required for human exposure studies. The pilot study employing the new method for examination of milk and canned fish samples was realized. Whereas in majority of canned fish products a wide spectrum of PFCAs, perfluorooctanesulphonic acid (PFOS) and perfluoro-1-octanesulphonamide (PFOSA) was detected, only in a few milk samples very low concentrations (LOQ levels) of PFOS and perfluorooctansulphonic acid (PFDS) were found.     

Improved extraction and identification by ultra performance liquid chromatography tandem mass spectrometry of phenolic compounds in burdock leaves

The simultaneous ultrasonic and microwave assisted extraction (UMAE) technique was first employed to obtain phenolics. The effects of UMAE variables including extraction time, microwave power, and solvent to solid radio on the yield of phenolics were investigated. The optimized conditions were as follows: solvent to solid ratio was 20:1 (ml/g), extraction time was 30 s, microwave power was 500 W and two times of extraction. Moreover, the phenolic yield of UMAE was higher than that by maceration, indicating a significant reduction of extraction time and an improvement of efficiency. The phenomenon is related to the strong disruption of leaf tissue structure by microwave induced expansion and ultrasonic shaking, which had been observed with the scanning electron microscopy. The phenolic compositions of the extract was then identified by ultra performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS), 10 compounds had been characterized, providing a more complete identification of phenolic compounds in burdock leaves than previously reported. The occurrence of benzoic acid and p-coumaric acid is reported for the first time. This study suggests that UMAE is a good alternative for the extraction of phenolics, with a great potential for industrial application. Also, UMAE provides a new sample preparation technique for characterization of the phenolic compounds from plants.     

高效液相色谱-串联质谱法快速测定6类食品中增效醚的残留

建立了水果、蔬菜、粮谷、油料、动植物脂类、动物源性食品等6类食品中增效醚残留量快速测定的液相色谱-质谱/质谱(LC-MS/MS)方法。样品盐析并除水后,用三氯甲烷提取,氟罗里硅土填料固相萃取柱净化,丙酮-三氯甲烷混合溶剂洗脱,以乙腈-0.1%甲酸为流动相,在Zobax SB C18液相色谱柱完成分离,并于电喷雾正离子多反应监测模式下质谱测定。考察了提取溶剂、净化方法、柱容量、仪器条件、基质效应对分析结果的影响。增效醚质量浓度在0.5～100μg/L范围内,线性相关系数(r)为0.9976,方法定量限(LOQ)为10μg/kg。17种食品基质添加LOQ、低MRL、2倍MRL、高MRL 4个不同浓度水平时,回收率在80.3%～96.3%之间,相对标准偏差为2.7%～14%,方法可以满足多种食品基质中增效醚残留量的定性和定量检测要求。     

Peptides trapping cocaine: docking simulation and experimental screening by solid phase extraction followed by liquid chromatography mass spectrometry in plasma samples

Two different hexapeptides were computationally designed and tested as selective SPE sorbent for cocaine. The amino acid residues used for designing the two hexapeptides, tested in SPE experiments, were, according to chemical function and interatomic distances, the most (QHWWDW) and the lowest (ESSIDH) preserved sequences in 4 proteins binding cocaine. The hexapeptide–cocaine complex was docked with different scoring functions combinations and resulting binding scores were compared with the SPE results. The extraction procedure for SPE was optimized considering volume loading, pH effect, and human plasma matrix interferences. Cocaine was loaded onto the modified resin cartridge at 10 ng mL⁻¹ and the peptide QHWWDW was found to have the highest recovery with the best retention at pH 7.5, in agreement with docking simulation. Retention experiments were carried out also on cocaine metabolites nor-cocaine, benzoylecgonine and ecgonine methyl ester. Except for nor-cocaine the retention of metabolites on resin modified with peptide QHWWDW decreased drastically confirming the peptide selectivity, and validating the simulation data. Compared to standard solutions, only a slight decrease in cocaine recovery was observed loading human plasma samples after a partial protein precipitation.     

Determination of thyreostats in urine and thyroid gland by ultra high performance liquid chromatography tandem mass spectrometry

Thyreostatic compounds could be illegally administered to animals in order to obtain a weight gain due to a higher retention of water in the edible tissue and the gastro-intestinal tract. In the European Union their use for animal production is banned since 1981. Recently a highly sensitive method exploiting the determination of thyreostats with 3-iodobenzylbromide prior to purification to determine thyreostats in urine and other matrices was reported. For the first time, the UPLC instrumentation was used to separate the 3-iodobenzyl derivatives of various thyreostats. The deuterated internal standards tapazole-d₃ and propylthiouracil-d₅ were for the first time used for the quantification of tapazole, thiouracil, methylthiouracil, propylthiouracil, phenylthiouracil and mercaptobenzimidazole. The confirmative quantitative liquid chromatographic tandem mass spectrometric (LC–MS/MS) method was validated according to Commission Decision 2002/657/EC. The decision limit (CCα) and the detection capability (CCβ) were found to be for all compounds below the recommended value of 10 μg kg⁻¹.     

Rapid residue analysis of fluoroquinolones in raw bovine milk by online solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry

Online solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry was used for the determination of 15 fluoroquinolones and one quinolone antibiotic in raw bovine and skimmed commercial milk. Milk samples were partially deproteinized and defatted by 15 min centrifugation and then subjected to online solid phase extraction. Chromatographic separation was achieved in less than 15 min. Identification and quantification of the compounds of interest were performed by selected reaction monitoring, using an electrospray ionization source. Relative recoveries were calculated for raw milk (at 0.5, 1 and 1.5 times the MRL, or assuming 30 ng/mL for non permitted compounds) and skimmed milk (at 30 ng/mL) and ranged between 65% and 123% (raw milk) or 78% and 109% (skimmed milk). Matrix interferences were also assessed and yielded significant suppression and enhancement effects, which, at the time of quantification, were corrected by the use of six isotopically labeled standards. Quality parameters of the method were established, and limits of detection of selected antibiotics in raw milk ranged from 0.01 to 1.93 ng/mL, while in skimmed milk from 0.03 to 4.23 ng/mL. The validation of the method has been carried out according to the requirements set by the 2002/657/EC regulation. Finally, the applicability of the method was tested by analysing 28 milk samples.     

Determination of cephalosporin antibiotics in water samples by optimised solid phase extraction and high performance liquid chromatography with ultraviolet detector

A reliable and robust analytical method based on solid phase extraction (SPE) and high performance liquid chromatography (HPLC) with ultraviolet (UV) detector was developed for the simultaneous determination of five cephalosporin antibiotics (Ceftazidime, Cefradine, Cefaclor, Cefotaxime and Cefoperazone) in various water samples. Under optimised conditions, it was applicable to preconcentrate up to 500?ml of water samples in the OASIS HLB cartridges with reasonable recoveries for all the cephalosporin antibiotics tested. Recoveries were as follows: deionised water, tap water and groundwater, between 84.2 and 98.9%; surface water, between 71.2 and 81.0%; influent and effluent of wastewater treatment plant (WWTP), between 56.9 and 72.1%. The method detection limits (MDLs) for different water samples were in the range of 26 to 59?ng?l^?1. Real water samples were analysed using the proposed approach to demonstrate the applicability and validation. Negative results were obtained for the tap water and groundwater. However, all the selected cephalosporin antibiotics were identified in the influent and effluent of a local WWTP at ng?l^?1–µg?l^?1 level. In addition, Ceftazidime was found in surface water with a concentration of 0.75–2.60?µg?l^?1. The results indicate that the ‘pseudo-persistent’ contamination of cephalosporin antibiotics in the water environment could not be neglected.     

Determination of fluoroquinolones in edible animal tissue samples by high performance liquid chromatography after solid phase extraction

In the present work, a rapid, accurate, and sensitive method has been developed for the quantitative determination of five fluoroquinolones (enoxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) in edible animal tissues (muscle tissue, liver, kidney, and eggs). The separation was accomplished on an Inertsil (250 x 4 mm) C8, 5 microm, analytical column, at ambient temperature within 15 min. The mobile phase consisted of a mixture of citric acid (0.4 mol L(-1))-CH3OH-CH3CN (87:9:4% v/v). UV detection at 275 nm yielded the following limits of detection: 100 pg per 20 microL injected volume for enoxacin, norfloxacin, and ciprofloxacin, 20 pg for ofloxacin, and 200 pg for enrofloxacin. Peaks in real samples were identified by means of a photodiode array detector. The method was validated in terms of intra-day (n = 8) and inter-day (n = 8) precision and accuracy. Tissue samples were purified from endogenous interference by solid-phase extraction using Oasis HLB cartridges. The solid-phase extraction protocol was optimized in terms of retention and elution. Recovery rates at fortification levels of 40, 60, and 80 ng/g ranged from 82.5% to 111.1%. The applicability of the method was examined using real samples from a chicken treated orally with the five studied fluoroquinolones.     

超高压液相色谱-串级质谱分析渔业水中7种激素药物

建立了同时测定渔业养殖水中氢化可的松、泼尼松、醋酸可的松、睾酮、甲睾酮、黄体酮及苯丙酸诺龙等7种激素残留药物的超高压液相色谱-电喷雾电离串联质谱(UPLC-ESI-MS/MS)分析方法.水样用HLB固相萃取柱净化、浓缩后,洗脱液经氮气吹干,残渣用乙腈-水(V∶V=1∶1)溶解,以乙腈和0.1％甲酸水溶液为流动相,经ZORBAXSB-C18色谱柱分离后进行LC-MS/MS多反应检测模式作定性定量分析.方法在0.5～40μggL或1～40μg/L范围具有良好的线性,相关系数大于0.997,检出限(S/N=3)为0.03～0.3μg/L,平均回收率为74.8％～113.0％,相对标准偏差为4.0％～16％.方法适用于渔业养殖水中7种激素的检测分析.     

Analysis of bisphenols in soft drinks by on-line solid phase extraction fast liquid chromatography-tandem mass spectrometry

In this study, an automated on-line solid-phase extraction coupled to fast liquid chromatography–tandem mass spectrometry (on-line SPE fast LC–MS/MS) method was developed for the simultaneous analysis of bisphenol A (BPA), bisphenol F (BPF), bisphenol E (BPE), bisphenol B (BPB) and bisphenol S (BPS) in canned soft drinks without any previous sample treatment. A C18 (12 μm particle size) loading column was used for the SPE on-line preconcentration before the liquid chromatography baseline separation of bisphenol compounds using a C18 Fused-Core™ (50 mm × 2.1 mm i.d.) column, which took less than 3 min. Gradient elution and heated electrospray were used to reduce matrix effect and improve ionization efficiency. To select the most intense and selective transitions, fragmentation studies were performed by multiple-stage mass spectrometry in an ion trap mass analyzer and tandem mass spectrometry in a triple quadrupole instrument, this latter instrument being used for quantitation in SRM mode. Quality parameters of the method were established and we obtained a simple, fast, reproducible (RSD values lower than 10%) and accurate (precision higher than 93%) method for the analysis of bisphenols in canned soft drinks at the ng L⁻¹ level using matrix-matched calibration.     

Rapid screening method for diuretics in doping control using automated solid phase extraction and liquid chromatography-electrospray tandem mass spectrometry

A new method has been developed for the routine detection of diuretics in urine samples collected from athletes. The method developed uses automated solid phase extraction (SPE) with analysis of the extracts by high performance liquid chromatography using electrospray ionisation tandem mass spectrometry. It requires only one injection per sample and is currently capable of detecting 35 diuretics and related compounds at the rate of five samples per hour. All parent compounds can be detected at urinary concentrations significantly below 100 ng/ml with the recovery of most analytes being greater than 80%.     

超高效液相色谱-串联质谱同时检测血液中29种农药

本文采用超高效液相色谱-串联质谱法(UPLC-MS/MS)和固相萃取法(SPE)建立了血液中29种农药同时筛查、定性、定量分析的方法,血液经4%磷酸水溶液稀释后,震荡10min,以8000r·min^-1转速离心10min,取上清液过3mL甲醇和3mL水活化好的Oasis Prime HLB(3cc,60mg)固相萃取小柱,使用3mL5%甲醇水淋洗,3mL乙腈甲醇混合溶剂(90:10)洗脱,接收洗脱液后在40℃条件下氮吹仪吹干,使用0.5mL初始流动相复溶,震荡10s后,过0.22μm水膜,装液质小瓶后进样分析。采用ACQUITY UPLC HSS C18色谱柱(150 mm×2.1mm,1.8μm)分离,流动相为0.1%甲酸乙腈-水/甲酸/甲酸铵(5mmol,pH=3),梯度洗脱,电喷雾电离正离子模式(ESI+),多反应选择离子监测模式(MRM)检测。29种农药的检出限为0.1 ng·mL^-1～5 ng·mL^-1,定量限为0.5 ng·mL^-1～10 ng·mL^-1,回收率为6...     

Determination of biocides as well as some biocide metabolites from facade run-off waters by solid phase extraction and high performance liquid chromatographic separation and tandem mass spectrometry detection

Biocides are used to protect buildings, boats, and other materials from microbial infestations. A huge variety of compounds are being used: isothiazolinones, e.g., to prevent bacterial growth in paints, triazines and phenylureas against algal growth on water exposed materials while carbamates are used against fungal investations. However these biocides can be leached from the respective materials. As these are very effective compounds it is important to know the concentrations of these biocides in the leachates as well as their leaching behaviour to assess their risk to the environment. In this study, a method for the determination of biocides from facade material run-off water by means of high performance liquid chromatography coupled to tandem mass spectrometry (HPLC–MS/MS) was developed. Due to the amphiphilic character and the expected varying pH-values in the samples, the extractions as well as the HPLC-method development proved to be demanding. The water samples (leachates) were buffered with a phosphate buffer to pH 7. As some of the biocides are very hydrophilic, different SPE cartridges were tested to identify the SPE material with the highest recovery rates for all compounds. For gaining a good separation, analyte trapping was performed on the HPLC column. Quantification was performed using a mass spectrometer in multi-reaction monitoring with two transitions per compound. The final recovery rates were conducted using a cartridge with a divenylbenzyl polymer sorbent. A combination of methanol and acetonitrile as eluents was used to reach recovery rates in the range of 70–100%. The limit of quantification for the compounds of interest ranged from 0.01 to 0.1 μg/L.     

Analysis of chlormequat and mepiquat by hydrophilic interaction chromatography coupled to tandem mass spectrometry in food samples

In this work a LC–MS/MS method for the determination of two quaternary ammonium growth regulators (chlormequat and mepiquat) in food is reported. The separation was based on hydrophilic interaction liquid chromatography (HILIC) without the use of ion-pair reagents. A gradient elution of acetonitrile and formic acid/ammonium formate buffer from 60 to 40% acetonitrile was enough to achieve a resolution >1.5 in less than 4.0 min. The HILIC system was coupled to a triple quadrupole mass spectrometer equipped with a heated electrospray probe (H-ESI) providing sub-pg LODs in SRM mode. A straightforward sample treatment (SPE C18 clean-up) was enough to provide MLODs at low ppb levels when analysing a range of food samples that covered different kinds of matrices such as fresh fruit, vegetables, fruit juices, baby food, bread, coffee and beer. Chlormequat was found in seven samples (0.8–126 ng/g) but mepiquat was only detected in bread and coffee samples (0.9–166 ng/g).     

Determination of ethyl glucuronide in hair samples by liquid chromatography/electrospray tandem mass spectrometry

A method for the determination of ethyl glucuronide (EtG) in hair samples, using liquid chromatography/electrospray tandem mass spectrometry (LC/ESI-MS/MS), was developed and validated. The treatment of hair samples was as follows: to 100 mg of washed (dichloromethane followed by methanol, 1 ml each) and cut (1-2 mm) material, 700 microl of water, 20 microl of internal standard solution (pentadeuterated EtG, D(5)-EtG, 500 microg/l) and 20 microl of methanol were added. Samples were incubated at 25 degrees C overnight and then ultrasonicated for 2 h. Finally, 8 microl of the centrifuged solution (13,000 rpm) were analyzed by LC/ESI-MS/MS in negative ion mode. The surviving ions of EtG and D(5)-EtG were monitored together with the following MRM transitions: m/z 221 --> 75, m/z 221 --> 85 (EtG) and m/z 226 --> 75, m/z 226 --> 85 (D(5)-EtG). The method exhibited a mean correlation coefficient better than 0.9998 over the dynamic range (3-2000 pg/mg). The lower limit of quantification (LLOQ) and the limit of detection (LOD) were 3 and 2 pg/mg respectively. The intra- and interday precision and accuracy were studied at four different concentration levels (3, 5, 56 and 160 pg/mg) and were always better than 7% (n = 5). Matrix effects did not exceed 20%. The method was applied to several hair samples taken from autopsies of known alcoholics, from patients in withdrawal treatment, from social drinkers, from adult teetotalers and from children not exposed to ethanol, with EtG concentrations globally ranging from < or =2 to 4180 pg/mg.     

在线固相萃取-超高效液相色谱/串联质谱法测定水中新烟碱类杀虫剂

采用在线固相萃取-超高效液相色谱/串联质谱技术建立了水中啶虫脒、噻虫胺、吡虫啉、噻虫啉、噻虫嗪、呋虫胺及烯啶虫胺7种新烟碱类杀虫剂的检测方法.样品滤膜过滤后,经HLB Dierect Connect HP在线固相萃取小柱富集纯化,以ACQUITY UPLC BEH C18为分析柱串联质谱进行检测,外标法定量.在线富集水...     

Liquid chromatography coupled with tandem mass spectrometry method for thirty-three pesticides in natural water and comparison of performance between classical solid phase extraction and passive sampling approaches

The aim of this study is to propose an analytical method for determining different classes of pesticides in water using LC-ESI-MS/MS. Two techniques of field-sampling and analyte extraction were used: solid phase extraction (SPE) of water samples from active sampling and field exposure of Polar Organic Chemical Integrative Samplers (POCIS). We have worked with thirty-three molecules representing eight pesticide classes: carbamates, chloroacetanilides, dicarboximides, morpholines, organophosphorous, phenylureas, strobilurines and triazines. First, liquid chromatography separation protocols and the optimization of the ESI-MS/MS parameters were developed. Then, the SPE step was optimized to obtain acceptable levels of recovery for the various classes of molecules. The matrix effect that may significantly lower the ionization efficiency with ESI interfaces was evaluated and minimized. The performances (limits of quantification, accuracy and precision) of the SPE and POCIS techniques were evaluated, and a comparison between the active and passive sampling techniques was carried out with a field application.     

超高效液相色谱-串联质谱法测定32种蔬菜中萝卜硫素

建立了超高效液相色谱-串联质谱(UHPLC-MS/MS)测定蔬菜中萝卜硫素的方法,并测定了32种常见蔬菜的萝卜硫素含量.取蔬菜冻干粉,利用内源黑芥子酶在pH 5的H3PO4缓冲液条件下酶解,酶解液经冷冻干燥后用乙酸乙酯提取,经减压浓缩后用50％乙腈-水(V/V)复溶.复溶液采用Shim-pack XR-ODS Ⅱ色谱柱...     

Fully automated determination of 74 pharmaceuticals in environmental and waste waters by online solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry

The present work describes the development of a fully automated method, based on on-line solid-phase extraction (SPE)-liquid chromatography-electrospray-tandem mass spectrometry (LC-MS-MS), for the determination of 74 pharmaceuticals in environmental waters (superficial water and groundwater) as well as sewage waters. On-line SPE is performed by passing 2.5 mL of the water sample through a HySphere Resin GP cartridge. For unequivocal identification and confirmation two selected reaction monitoring (SRM) transitions are monitored per compound, thus four identification points are achieved. Quantification is performed by the internal standard approach, indispensable to correct the losses during the solid phase extraction, as well as the matrix effects. The main advantages of the method developed are high sensitivity (limits of detection in the low ng L⁻¹ range), selectivity due the use of tandem mass spectrometry and reliability due the use of 51 surrogates and minimum sample manipulation. As a part of the validation procedure, the method developed has been applied to the analysis of various environmental and sewage samples from a Spanish river and a sewage treatment plant.