A novel sorbent for the determination of clenbuterol in bovine liver.

The use of three C18 sorbents in matrix solid phase dispersion (MSPD) for the determination of clenbuterol in bovine liver fortified at 5 ng g-1 is described. MSPD grade C18 sorbents give rise to more efficient blending and packing of the material for subsequent washing and analyte elution in comparison with a non-MSPD grade C18 sorbent. Following enzymatic deconjugation of the liver extracts, radioimmunoassay is used as the method of determination. The mean recovery of clenbuterol with all sorbents is comparable and within the range 86-96% in two intra-assay studies (n = 3). The liver extracts in each case are highly coloured. The variation in recovery is observed to be lowest with MSPD grade C18 (end-capped). This sorbent was used in further studies to evaluate the use of solid phase extraction (SPE), post MSPD, with normal phase aminopropyl or mixed mode cation exchange columns for extract purification. The mean recovery of clenbuterol (n = 4, inter-assay study) following MSPD and normal phase SPE clean-up was 95 +/- 15% and 89 +/- 9% at fortification levels of 1 and 2.5 ng g-1, respectively.     

同位素稀释超高效液相色谱串联质谱法同时测定牛奶中的克伦特罗、氯霉素与己烯雌酚

建立了同时测定牛奶中克伦特罗、氯霉素和己烯雌酚残留量的同位素稀释超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法.牛奶样品无需蛋白沉淀,直接经HLB小柱净化及水和正己烷淋洗,由乙酸乙酯洗脱后进行分析.采用Acquity UPLC(○R)BEH C18色谱柱进行分离,以乙酸铵溶液-乙腈作为流动相进行梯度洗脱,MR...     

Development and validation of stability-indicating HPLC method for the simultaneous determination of paracetamol, tizanidine, and diclofenac in pharmaceuticals and human serum

A method is described for the simultaneous determination of paracetamol, tizanidine, and diclofenac in mixtures. The method was based on HPLC separation of the three drugs followed by UV detection at 254 nm. The separation was carried out on a Hypersil ODS, C18 (250 x 4.6 mm id, 10 microm particle size) column using the mobile phase aqueous 0.2% ammonium carbonate-methanol (60 + 40, v/v) at a flow rate of 1 mL/min. The linear regression analysis data were used for the regression curve in the range of 170-10 000 ng/mL for paracetamol, 120-10 000 ng/mL for tizanidine, and 20-10 000 ng/mL for diclofenac. No chromatographic interference from tablet excipients was found. In order to check the selectivity of the proposed method, degradation studies were carried out using hydrolysis (acid, basic, and neutral), thermolysis, and oxidation. The developed method, after being validated in terms of precision, robustness, recovery, LOD, and LOQ, was successively applied to the analysis of pharmaceutical formulations and human serum.     

Multi-residue analysis of avermectins and moxidectin by ion-trap LC-MSn

A multi-residue method was developed and validated for the quantitation and confirmation of avermectins and moxidectin residues in bovine liver. Target analytes were extracted from liver homogenate using C8 solid phase cartridges, chromatographed under basic pH conditions in order to promote the formation of analyte anions, and detected by ion-trap mass spectrometry (MS) in negative ion mode using an atmospheric pressure chemical ionization interface (APCI). The method provided detection capabilities (CC beta, where beta = 0.05) for eprinomectin, abamectin, doramectin, moxidectin and ivermectin of 3.1, 3.2, 2.2, 4.0 and 3.2 ng g-1 liver respectively, well below their respective maximum residue limits (MRLs). The critical concentrations for MRL compliance (CC alpha, where alpha = 0.01) were 840, 28, 130, 130 and 130 ng g-1 respectively. Analysis of liver fortified at the appropriate MRLs gave recoveries (% +/- RSD) of 70.9 +/- 11.6 (n = 14), 69.1 +/- 3.9 (n = 13), 65.9 +/- 6.4 (n = 19), 69.7 +/- 9.3 (n = 19) and 73.2 +/- 10.5 (n = 19), respectively, for each analyte. Calibration curves fitted a second order polynomial function (R2 > or = 0.9978) over a wide range of concentrations (0 to 10,000 ng ml-1). The detection of two daughter-ions for each analyte allowed for quantitation and the confirmation of identity. The method is suitable for application in European Union statutory veterinary drug residue surveillance programmes, since it fulfills appropriate analytical criteria, and has the particular advantage of enabling high throughput multi-residue quantitation and confirmation of the target analytes.     

超高效液相色谱-串联质谱法同时测定浓缩果汁中的18种多酚物质

建立了浓缩果汁中18种多酚物质的超高效液相色谱(UPLC)-串联质谱(MS/MS)检测方法.样品经水稀释,HLB固相萃取净化,浓缩蒸干后用甲醇和0.1%甲酸定容.采用Acquity UPLC BEH C18 (1.7μm ×2.1 mm ×50 mm)色谱柱分离,以甲醇和0.1%甲酸为流动相,在0.3 ml,·min-...     

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62.4%~97.4%,基质效应为82.8%~109%,相对标准偏差小于10.3%,相关系数均大于0.99,线性关系良好范围为10 ng·mL^-1~1000ng·mL^-1。本文方法灵敏度高,可以对血液中29种农药成分进行筛查、定性、定量分析,能够满足实际血液样品中农药成分检测的需求。     

Determination of benzo[a]pyrene tetrols by column-switching capillary liquid chromatography with fluorescence and micro-electrospray ionization mass spectrometric detection

The present work displays capillary liquid chromatographic column switching methodology tailored for determination of benzo[a]pyrene tetrol isomers in biological matrices using on-line fluorescence and micro-electrospray ionization mass spectrometric detection. A well-established off-line crude solid phase extraction procedure was used in order to make the method compatible with several biological matrices. The solid phase extraction eluates were evaporated to dryness, redissolved in 1.0 ml methanol:water (10:90, v/v), loaded onto a 0.32 mm I.D. x 40 mm 5 microm Kromasil C(18) pre-column for analyte enrichment and back-flushed elution onto a 0.30 mm I.D. x 150 mm 3.5 microm Kromasil C(18) analytical column. The samples were loaded with a flow rate of 50 microl min(-1) and the tetrols were separated at a flow rate of 4 microl min(-1) with an acetonitrile:10 mM ammonium acetate gradient from 10 to 90%. A sample loading flow rate up to 50 microl min(-1) was allowed. The fluorescence excitation and emission were set to 342 and 385 nm, respectively, while mass spectrometric detection of the benzo[a]pyrene tetrols was obtained by monitoring their [M - H](-) molecular ions at m/z 319. The method was validated over the concentration range 0.1-50 ng ml(-1) benzo[a]pyrene tetrols in a cell culture medium with 100 microl injection volume, fluorescence detection and the first eluting tetrol isomer as model compound, resulting in a correlation coefficient of 0.993. The within-assay (n= 6) and between-assay (n= 6) precisions were determined to 2.6-8.6% and 3.8-9.6%, respectively, and the recoveries were determined to 97.9-102.4% within the investigated concentration range. The mass limit of detection (by fluorescence) was 3 pg for all the tetrol isomers, corresponding to a concentration limit of detection of 30 pg ml(-1) cell culture medium. The corresponding mass spectrometric mass limits of detection were 4-10 pg, corresponding to concentration limits of detection of 40-100 pg ml(-1) cell culture medium.     

High performance liquid chromatographic determination of diazinon, permethrin, DEET (N, N-diethyl-m-toluamide), and their metabolites in rat plasma and urine

A rapid method was developed for the analysis of the insecticide (A) diazinon (O,O-diethyl O-2-isopropyl-6-methylpyridimidinyl) phosphorothioate, its metabolites (B) diazoxon (O,O-diethyl O-2-isopropyl-6-methylpyridimidinyl) phosphate, and (C) 2-isopropyl-6-methyl-4-pyrimidinol, the insecticide (D) permethrin [3-(2,2-dichloro-ethenyl)-2,2-dimethylcyclopropanecarboxylic acid (3-phenoxyphenyl)methylester], its metabolites (E) m-phenoxybenzyl alcohol, and (F) m-phenoxybenzoic acid, the insect repellent (G) DEET (N,N-diethyl-m-toluamide), and its metabolites (H) m-toluamide and (I) m-toluic acid in rat plasma and urine. The method is based on using C18 Sep-Pak cartridges (Waters Corporation, Milford, Mass., U.S.A.) for solid phase extraction and high performance liquid chromatography with a reversed phase C18 column, and absorbance detection at 230 nm for compounds A, B, and C, and at 210 nm for compounds D-I. The compounds were separated using a gradient from 1% to 99% acetonitrile in water (pH 3.0) at a flow rate ranging between 1 and 1.7 mL/min in a period of 17 min. The limits of detection were ranged between 20 and 100 ng/mL, while limits of quantification were 80-200 ng/mL. The relationship between peak areas and concentration was linear over a range of 100-1000 ng/mL. This method was applied to determine the above insecticides and their metabolites following dermal administration in rats.     

Photodegradation and flow-injection determination of simetryn herbicide by luminol chemiluminescence detection

A novel and simple flow injection chemiluminescence method is reported for the determination of simetryn, a common herbicide. The method is based on the direct oxidation of luminol by the photoproducts of the simetryn in alkaline medium in the absence of catalyst/oxidant. The linear concentration range was 0.01 - 2 microg mL(-1) simetryn with a correlation coefficient (r(2)) of 0.9997 and relative standard deviations (RSD; n = 4) in the range of 0.9 - 2.3%. The limit of detection (S/N = 3) was 7.5 ng mL(-1) with a sample throughput of 100 h(-1). The proposed method has been applied to determine simetryn in natural waters using Sep-Pak C(18) cartridges for solid phase extraction (SPE) procedure. The recoveries were in the range of 97 +/- 1 to 104 +/- 2%. The mechanism of chemiluminescence reaction has also been discussed briefly.     

Rapid determination of polycyclic aromatic hydrocarbons in tea infusion samples by high-performance liquid chromatography and fluorimetric detection based on solid-phase extraction

This paper describes a method for the determination of PAHs in black, green and decaffeinated tea infusion samples. The method is based on the solid phase extraction of the PAHs using Sep-Pak vac tC-18 cartridges. The PAHs are then eluted from the cartridges with dichloromethane. Quantification and detection are carried out by HPLC with a fluorimetric detector using a program of excitation and emission wavelength pairs. Recoveries at concentration levels in the range 190-1790 ng l-1 were higher than 65% for all PAHs except dibenz[a,h]anthracene, for which it was around 54%. The mean content of PAHs was in the range 28.7-112 ng l-1 in the tea infusions, with relative standard deviations between 2 and 18% (n = 4).     

Determination of dexamethasone in feed by TLC and HPLC

Two detection methods are described for the determination of dexamethasone in feed, which may be used as screening and confirmatory methods. The procedures were developed after studying different extraction and clean-up procedures: feed extraction was optimized using methylene chloride and hexane followed by a tandem solid-phase clean-up step with silica and C18 cartridges. The confirmatory method presented is based on normal-phase high-performance liquid chromatography on a Diol 5 microns column, with hexane-propan-2-ol (90:10 v/v) as mobile phase, followed by diode array detection and confirmation. All parameters are discussed, especially the extraction and clean-up steps. Recovery studies after application of the proposed method to different kinds of feed samples spiked with dexamethasone at levels between 120 and 1600 ng g-1 yielded a mean value of 55.4% with an overall standard deviation of 15.6%. The proposed procedure allows the determination of dexamethasone in feed at levels lower than 50 ng g-1.     

Simultaneous determination of perfluoroalkyl phosphonates, carboxylates, and sulfonates in drinking water

A trace analytical method based on high performance liquid chromatography coupled to quadrupole time-of-flight high resolution mass spectrometry was developed for simultaneous determination of perfluoroalkyl phosphonates (PFPAs, carbon chain lengths C6,8,10), perfluoroalkyl carboxylates (PFCAs, C5-12), and perfluoroalkyl sulfonates (PFSAs, C4,6,8,10) in drinking water (tap water). Analytes were enriched on a mixed mode co-polymeric sorbent (C8+quaternary amine) using solid phase extraction. Chromatographic separation was achieved on a Zorbax Extend C18 reversed phase column using a mobile phase gradient consisting of water, methanol, and acetonitrile containing 2mM ammonium acetate and 5 mM 1-methyl piperidine. The mass spectrometer was operated in electrospray negative ion mode. Use of 1-methyl piperidine in the mobile phase resulted in a significant increase in instrument sensitivity for PFPAs through improved chromatographic resolution, background suppression, and increased ionization efficiency. Method detection limits for extraction of 500 mL tap water were in the ranges of 0.095-0.17 ng/L, 0.027-0.17 ng/L, and 0.014-0.052 ng/L for PFPAs, PFCAs, and PFSAs, respectively. Whole method recoveries at a spiking level of 0.5 ng/L to 500 mL HPLC grade water were 40-56%, 56-97%, and 55-77% for PFPAs, PFCAs, and PFSAs, respectively. A matrix effect (signal enhancement) was observed in the detection of PFPAs in tap water extracts, leading to calculated recoveries of 249-297% at a 0.5 ng/L spiking level. This effect resulted in an additional improvement of method sensitivity for PFPAs. To compensate for the matrix effect, PFPAs in tap water were quantified using matrix-matched and extracted calibration standards. The method was successfully applied to the analysis of drinking water collected from six European countries. PFPAs were not detected except for perfluorooctyl phosphonate (PFOPA) at close to the detection limit of 0.095 ng/L in two water samples from Amsterdam, the Netherlands. Highest levels were found for perfluorobutane sulfonate (PFBS, 18.8 ng/L) and perfluorooctanoate (PFOA, 8.6 ng/L) in samples from Amsterdam as well as for perfluorooctane sulfonate (PFOS, 8.8 ng/L) in tap water from Stockholm, Sweden.     

高效液相色谱-串联质谱法同时测定农田土壤中的六溴环十二烷和四溴双酚A

建立了加速溶剂萃取/高效液相色谱-三重四极杆串联质谱(ASE/HPLC-MS/MS)批量检测农田土壤中六溴环十二烷(HBCDs)和四溴双酚A(TBBPA)残留的分析方法。土壤样品经加速溶剂萃取,Sep-pak C18固相萃取柱净化后,在多反应监测(MRM)负离子电喷雾模式下进行HPLC-MS/MS分析。色谱柱为X Bridge C18反相柱(150 mm×2.1 mm×3.5μm),流动相为梯度变化的甲醇和水溶液。在最佳实验条件下,六溴环十二烷和四溴双酚A在0.50~200.0μg/L范围内线性关系良好(r≥0.998),方法检出限(S/N≥3)为1.80~10.0 ng/kg。在1.0~40.0μg/kg添加水平内,平均加标回收率为73.8%~106.9%,相对标准偏差(RSD)为5.8%~11.2%。采用该方法分析了我国某区域内表层土壤样品的HBCDs和TBBPA,得到理想的分析效果。     

Determination of tricyclic antidepressants in human plasma using pipette tip solid-phase extraction and gas chromatography-mass spectrometry

A method for the simultaneous extraction of four tricyclic antidepressants from human plasma samples using pipette tip SPE with MonoTip C(18) tips is presented. Human plasma (0.1 mL) containing four tricyclic antidepressants (amitriptyline, amoxapine, imipramine, and trimipramine) and an internal standard (IS), protriptyline, was mixed with 0.4 mL of distilled water and 100 microL 1 M NaOH solution. After centrifugation of the mixture, the supernatant was extracted to the C(18) phase of the tip by 20 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained in the tip were eluted with methanol by five repeated aspirating/dispensing cycles. Without evaporation and reconstitution, the eluate was directly injected into a gas chromatograph injector and detected by a mass spectrometer with SIM in the positive-ion electron impact mode. Recovery of the four antidepressants and IS spiked into human plasma was 80.2-92.1%. The regression equations for the four antidepressants showed excellent linearity in the range of 0.2-40 ng/0.1 mL. LODs and LOQs for the four drugs were 0.05-0.2 ng/0.1 mL and 0.2-0.5 ng/0.1 mL, respectively. Intra- and interday CVs for the four drugs in plasma were no greater than 9.5%.     

固相萃取/高效液相色谱法测定化妆品中5种抗组胺药物残留

建立了固相萃取/高效液相色谱(SPE/HPLC)测定化妆品中5种抗组胺药物(多西拉敏、曲吡那敏、溴苯那敏、苯海拉明、氯苯沙明)残留的分析方法。试样经三氯乙酸溶液超声提取,PCX柱净化后,以甲醇-磷酸盐缓冲溶液为流动相,经C18柱分离后进行HPLC检测。5种抗组胺药物在5.0～100 mg/L范围内均呈良好的线性关系,线性系数均大于0.999。在5.0、10.0、25.0 mg/kg 3个加标水平下的平均回收率为92%～108%,相对标准偏差(RSD,n=6)为2.1%～4.2%,检出限为0.5～1.0 mg/L。该方法灵敏度高、重现性好、定量准确。     

Determination of parabens in shampoo using high performance liquid chromatography with amperometric detection on a boron-doped diamond electrode

Methylparaben (MePa), ethylparaben (EtPa) and propylparaben (PrPa) have been widely used, among others, as chemical preservatives in cosmetics, drugs and foods. As these compounds are linked with allergies, dermatitis and estrogenic properties, it is necessary to control the concentration of these substances in different matrices. The aim of this paper are: to evaluate the electrochemical behavior of parabens on the boron-doped diamond (BDD) electrode and the development of a chromatographic method, with electrochemical detection (HPLC-ED), for determination of parabens in shampoo. A BDD (8000 ppm) electrode was adapted in a thin layer mode analytical cell consisting of a stainless steel and a platinum wire as reference and auxiliary electrodes, respectively. Chromatographic separations were obtained with a reversed phase C8 analytical column and a mobile phase of 0.025 mol L⁻¹ disodium phosphate, pH 7.0, and acetonitrile (40:60, v/v), delivered at a flow rate of 1.0 mL min⁻¹. Sample preparation was performed by solid phase extraction using C18 cartridges and acetonitrile for elution. Benzylparaben was employed as internal standard. The HPLC-ED method developed, using the BDD electrode, was validated for the determination of parabens in shampoos and presented adequate linearity (>0.999), in the range of 0.0125-0.500% (w/w), detectability 0.01% (w/w), precision (RSD of 2.3-9.8%) and accuracy (93.1-104.4%) and could be applied for routine quality control of shampoos containing MePa, EtPa and PrPa.     

鱼肉中微囊藻毒素的高效液相色谱法分析

应用反相高效液相色谱法分析了鱼肉中藻毒素的含量。用BDS C18色谱柱,以水（含1％三氟乙酸）：甲醇＝30：70（V／V）溶液为流动相,238nm紫外检测。鱼肉样品用甲醇－水和丙酮混合溶剂提取,经正已烷萃取后,将有机相弃去,水相用固相萃取柱净化后进行高效液相色谱分析。该法检测限为10ng/g,峰面积标准曲线在50－250ng范围内有良好线性关系,平均回收率为85．1％－88．2％。     

固相萃取-气相色谱-质谱法测定利多卡因代谢物单乙基甘氨酰二甲苯胺的血药浓度

建立了固相萃取-气相色谱-质谱(GC-MS)测定利多卡因代谢物单乙基甘氨酰二甲苯胺(MEGX)血药浓度的方法。血清中的MEGX采用固相萃取小柱萃取、GC-MS测定。色谱条件为：HP-5MS毛细管柱(15 m×0.25 mm×0.1 μm),初始柱温100 ℃,保持1 min后以40 ℃/min速率升温至200 ℃,保持0.5 min;进样口温度250 ℃;分流进样,分流比1∶1,进样量2 μL;载气为氦气,流量为1.0 mL/min。质谱条件为:离子源温度230 ℃,电子轰击电离,电子能量70 eV,选择离子检测（m/z 58(MEGX)、 m/z 86(普鲁卡因,内标)）。结果表明,MEGX在血清中的浓度在1.562～25 ng/mL范围内的线性关系良好,相关系数0.9981,最低检测限为0.5 ng/mL,不同浓度MEGX的萃取回收率在80.1%～85.7%之间。实验证明该方法快速、准确,选择性好,灵敏度高,适合用于血清中微量MEGX的测定。     

An improved HPLC-ED method for monitoring plasma levels of clozapine and its active metabolites in schizophrenic patients

Summary An HPLC method with electrochemical detection has been developed for the determination of clozapine and its main metabolites, desmethylclozapine and clozapine N-oxide, in human plasma. An accurate pretreatment of the biological samples was implemented by means of solid phase extraction (SPE) on HLB cartridges. This improved pretreatment, together with a new mobile phase, allows for the accurate determination of clozapine N-oxide, which could not be quantitated by a previous method. The method uses only 100 μL of plasma for one complete analysis and shows good recovery values for all three analytes. The eluates from the SPE procedure were chromatographed in a reversed phase C18 column using a mobile phase composed of phosphate buffer, acetonitrile and methanol. Clozapine, desmethylclozapine and clozapine N-oxide were eluted in less than 10 minutes, without any interference from the biological matrix. Linearity was observed over the 2.50–150 ng mL⁻¹ (clozapine and desmethylclozapine) or 1.25–75 ng mL⁻¹ clozapine N-oxide) range for the three analytes, with satisfactory repeatability values. The limit of detection was 0.3 ng mL⁻¹ for clozapine and desmethylclozapine, samples of patients treated with Leponex gave good results. No interference from other common central nervous system drugs was found. This method seems to be a useful tool for pharmacokinetic studies and for clinical monitoring, because of its need for small plasma samples and its high sensitivity and selectivity.     

Identification and quantification of 34 drugs and toxic compounds in blood,urine, and gastric content using liquid chromatography with tandem mass spectrometry

A liquid chromatography with tandem mass spectrometry method was developed for the simultaneous screening of 34 drugs and poisons in forensic cases. Blood (0.5 mL, diluted 1:1 with water) or 1.0 mL of urine was purified by solid‐phase extraction. Gastric contents (diluted 1:1 with water) were treated with acetonitrile, centrifuged, and supernatant injected. Detection was achieved using a Waters Alliance 2695/Quattro Premier XE liquid chromatography tandem mass spectrometry system equipped with electrospray ionization, operated in the multiple reaction monitoring modes. The method was validated for accuracy, precision, linearity, and recovery. The absolute recovery of drugs and toxic compounds in blood was greater than 51% with the limit of detection in the range of 0.02–20 ng/mL. The absolute recovery of drugs and toxic compounds in urine was greater than 61% with limit of detection in the range of 0.01–10 ng/mL. The matrix effect of drugs and toxic compounds in urine was 65–117% and 67–121% in blood. The limit of detection of drugs and toxic compounds in gastric content samples were in the range of 0.05–20 ng/mL. This method was applied to the routine analysis of drugs and toxic compounds in postmortem blood, urine, and gastric content samples. The method was applied to actual forensic cases with examples given.