Analysis of emerging organic contaminants in poultry manure by gas chromatography–tandem mass spectrometry

A multiresidue method was developed for the determination of 19 emerging organic contaminants (pharmaceutical drugs, personal care products, and bisphenol A) in poultry manure. Lyophilized samples of manure were extracted by ultrasound‐assisted matrix solid‐phase dispersion and the extracts were analyzed by gas chromatography with tandem mass spectrometry after derivatization. Analysis of spiked poultry manure samples, at levels ranging from 25 to 150 ng/g, gave satisfactory recovery results for all the compounds, with values from 67 to 106%. The developed procedure provided detection limits that ranged from 0.9 to 2.2 ng/g. Finally, the validated method was applied to poultry manure samples collected from 23 poultry farms in Spain. Salicylic acid was found in most of the samples analyzed at levels up to 2501 ng/g, whereas, methyl paraben, orthophenylphenol, ibuprofen, paracetamol, and carbamazepine were detected at levels up to 250 ng/g. Composting of manure showed an important decrease in the levels of the detected contaminants.     

高效液相色谱-蒸发光散射检测法在烟用香精料液中水溶性糖及山梨醇分析中的应用

建立了高效液相色谱-蒸发光散射(HPLC-ELSD)同时检测烟用香精料液中6种水溶性糖及山梨醇的分析方法。方法选用Isolute ENV+固相萃取(SPE)小柱净化样品提取液,以Prevail Carbohydrate ES高效糖柱(250 mm×4.6 mm, 5 μm)作为分析柱,以乙腈和水(75:25, v/v)作为流动相,在1.0 mL/min流速下实现目标物的良好分离;蒸发光散射检测器漂移管温度为79 ℃,载气流速为2.0 L/min。方法针对各目标物建立双对数工作曲线,线性范围约为0.06～1.2 g/L,检出限为12～26 mg/L,样品加标回收率为88%～109%。针对蒸发光散射检测器的双对数工作曲线,通过实验进行分析对比,并结合前人的工作,指出目标物的物理化学性质及其在色谱柱上的保留状态和流动相的洗脱能力等都是影响检测信号的因素。     

反相高效液相色谱法分离测定烟草中的多酚类化合物

对植物中9种多酚类化合物的色谱分离条件进行了优化,分别探讨了流动相组成、流动相中醋酸浓度、醋酸溶液与甲醇的比例对保留时间的影响,确定了梯度分离条件,并对9种天然多酚类化合物进行了定量分析。该方法的检测限为13.26~59.29 mg/kg (S/N=3)。在3.0～100.0 mg/L 范围内呈良好的线性关系,相关系数r2为 0.9979~0.9999。9种待测化合物的加标回收率为96.8%~108%,相对标准偏差(RSD)小于3.8% (n=3)。用80%甲醇超声提取烟草样品,并通过优化的色谱条件对其进行分析,测定了实际烟草样品中芸香苷和绿原酸的含量。结果表明,该方法具有一定的实用价值。     

Simultaneous determination of simazine,cyanazine, and atrazine in honey samples by dispersive liquid–liquid microextraction combined with high‐performance liquid chromatography

A rapid and simple sample preparation method was developed for simultaneous determination of three triazine herbicides in honey samples. The selected herbicides were extracted from honey samples by ionic liquid dispersive liquid–liquid microextraction, separated on a C₁₈ column (250 mm × 4.6 mm id, 5 μm) using acetonitrile and H₂O as the mobile phase with gradient elution, and then detected by high‐performance liquid chromatography. The parameters, such as the type and volume of the extraction and disperser solvent, ion strength, pH, extraction time, and centrifuge time were optimized in order to provide the excellent extraction performance. Good linearity was showed for all the target herbicides over the tested concentration range with correlation coefficient higher than 0.994. Three spiked levels (0.005, 0.05, 0.10 mg/kg) were applied for determination of the recoveries of the targets in honey samples in the range of 80–103% with relative standard deviations not larger than 10.6%. The limits of quantification for the analytes ranged between 1.5 and 4.0 μg/kg. The developed method was applied for determination of the target compounds residues in real samples.     

Development of a precolumn derivatization HPLC method with diode‐array detection for the determination of amino sugars in peat and soil humic acids

The work is focused on the development of a high‐performance liquid chromatography method with diode‐array detection for the separation and quantitation of the three most abundant amino sugars; d ‐glucosamine, d ‐galactosamine, and d ‐mannosamine. The high‐performance liquid chromatography separation was carried out by reversed‐phase chromatography on Chromolith Performance RP‐18e monolithic column after acid hydrolysis (5 M HCl) and precolumn derivatization of samples using diethyl ethoxymethylenemalonate. Gradient elution and a mobile phase composed of ammonium formate buffer solution (10 mmol/L, pH 3.60) and methanol with flow rate of 1.0 mL/min were used. The monitoring wavelength was set at 280 nm. The limits of detection and quantitation for analytes ranged from 0.017 to 0.122 mg/L and from 0.057 to 0.407 mg/L, respectively. The proposed method was successfully applied for the determination of amino sugars in samples of humic acids isolated from different soils and peat.     

离子色谱-抑制型电导检测牛肝菌中胆碱、腐胺和尸胺

建立离子色谱-抑制型电导检测牛肝菌中胆碱、腐胺和尸胺的方法。牛肝菌干片样品经7 mmol/L甲烷磺酸溶液提取,过滤膜,经反相固相萃取柱净化后进样分析。胆碱、腐胺、尸胺与样品中共存离子在IonPac CS17（250 mm×4 mm）阳离子交换色谱柱上可实现较好分离。以7 mmol/L甲烷磺酸为淋洗液等度淋洗,25 min可完成一次样品测定。胆碱、腐胺和尸胺的检出限（S/N=3）分别为0.002、0.002和0.003 mg/L,具有较宽的线性范围（0.01~10 mg/L）,样品加标回收率为91.6%~100.2%。该方法简便、选择性好、灵敏度高,适用于牛肝菌中胆碱、腐胺和尸胺的检测分析。     

Using subcritical/supercritical fluid chromatography to separate acidic,basic, and neutral compounds over an ionic liquid-functionalized stationary phase

We packed an ionic liquid (IL)-functionalized stationary phase – based on 1-octyl-3-propylimidazolium chloride covalently bounded to silica gel – into a 3.2 mm × 250 mm column for the simultaneous separation of acidic, basic, and neutral compounds using carbon dioxide subcritical/supercritical fluid chromatography (SFC), and examined the effects of the pressure, temperature, co-solvents, and additives on the retention behavior of the analytes. The model compounds tested for SFC separation are acetaminophen, metoprolol, fenoprofen, ibuprofen, naphthalene, and testosterone. The data indicate that hydrogen-bonding and hydrophobic interactions between the analytes and the IL-modified stationary phase seem to involve in the separation process. Simultaneous separation of acidic, basic, and neutral compounds via SFC was successful at a co-solvent content of 20% MeOH, a pressure of 110 bar, and a column temperature of 35 °C. The relative standard deviations of the retention times and peak areas at 50 ppm were all less than 4 and 8% (n = 6), respectively.     

Simple,efficient, and eco‐friendly sample preparation for simultaneous determination of paracetamol and chloramphenicol in meat

We have developed and validated a simple, eco‐friendly, and reliable method to simultaneously determine paracetamol and chloramphenicol in meat with ultra performance liquid chromatography and tandem mass spectrometry. The samples were firstly extracted with ethylenediaminetetraacetic acid–McIlvaine's buffer and then purified by solid‐phase extraction by using a novel core‐shell polyaniline/polyacrylonitrile nanofibers mat. Compared with existing methods for the two analytes, the proposed method was simplified greatly with much fewer sample preparation steps, consumed much less time (< 2 min per sample) and organic solvent (0.7 mL per sample). Low detection levels (0.15–0.20 µg/kg for paracetamol, 0.01 µg/kg for chloramphenicol) with good precision and recoveries of the target compounds were obtained. The proposed method was applied to determine the residual paracetamol and chloramphenicol in pork, chicken, and beef samples, and the test results were consistent with those using the Chinese national standard methods, which demonstrates the reliability and practicality of the new method.     

固相萃取-超高效液相色谱分离测定洗涤用品中4种荧光增白剂

建立了固相萃取净化结合超高效液相色谱-二极管阵列检测器(UPLC-DAD)同时检测洗衣液、洗衣粉等洗涤用品中荧光增白剂351、85、28和71的分析方法。样品经2%（体积分数）甲酸水溶液-甲醇提取,经WAX固相萃取小柱净化后,采用Phenomenex Synergi Max-RP色谱柱(150 mm×2.0 mm),以乙腈-10 mmol/L乙酸铵为流动相实现待测物(包括顺式和反式异构体)的良好分离,以二极管阵列检测器检测,结合保留时间和光谱图定性,以标准曲线定量。结果表明,4种荧光增白剂在0.05～180 mg/L范围内线性关系良好,相关系数均大于0.9993;方法定量限(S/N=10)为1.5～15 mg/kg;添加水平为5～1500 mg/kg时,回收率为84.9%～105%,相对标准偏差(RSD, n=6)为3.2%～6.1%。应用本方法分析了15个样品,阳性样品检出率为53.3%。该法前处理简单,回收率高,精密度好,适用于洗涤用品中4种荧光增白剂的测定。     

Cellulose membrane modified with polypyrrole as an extraction device for the determination of emerging contaminants in river water with gas chromatography–mass spectrometry

In this study, a simple, efficient, and reusable device based on cellulose membranes modified with polypyrrole was developed to extract 14 emerging contaminants from aqueous matrices. For chemical polymerization, a low‐cost cellulose membrane was immersed in 0.1 mol/L pyrrole and 0.5 mol/L ammonium persulfate for 40 min in an ice/water bath. The cellulose membranes modified with polypyrrole were accommodated in a polycarbonate holder suitable for solid‐phase extraction disks. Solid‐phase extraction parameters that affect extraction efficiency, such as sample volume, pH, flow rate, and desorption were optimized. Subsequently, determination of target compounds was performed by gas chromatography with mass spectrometry. The linear range for analytes ranged from 0.05 to 500 μg/L, with coefficients of determination above 0.990. The limits of quantification varied between 0.05 and 10 μg/L, with relative standard deviations lower than 17%. The performance of the proposed cellulose membranes modified with polypyrrole device for real samples was evaluated after extraction of emerging contaminants from a river water sample from the city of Curitiba, Brazil. Bisphenol A (6.39 μg/L), caffeine (17.83 μg/L), and paracetamol (19.28 μg/L) were found in these samples.     

Development and validation of a sensitive UHPLC‐MS/MS method for the simultaneous analysis of tramadol,dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics

The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O‐desmethyltramadol, dsmethyl‐chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid–liquid extraction method using ethyl acetate–diethyl‐ether (1:1). Extracted samples were analyzed by ultra‐high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC‐ESI‐MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 μL/min into a Hypersil‐Gold C₁₈ column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3–9.8 and ?1.7–4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide. Copyright © 2014 John Wiley & Sons, Ltd.     

Determination of antibiotics in feedstuff samples by microemulsion electrokinetic chromatography using fullerene as additive

A microemulsion electrokinetic chromatography method was developed for the simultaneous detection and quantification of ciprofloxacin, norfloxacin, sulfamethoxazole, tetracycline, and oxytetracycline in feedstuff samples. The BGE composition was optimized by applying a Taguchi parameter design and consisted of phosphate 30 mmol/L, Tween‐80 0.01 mmol/L, and fullerene 3 μmol/L, and adjusted to pH 8.0; the addition of surfactant and fullerene modifies the mobility of the analytes improving their resolution. Theoretical studies showed π‐π and van der Waals interactions between antibiotic molecules and fullerene used as a pseudostationary phase. Under optimal conditions, limits of detection ranged from 0.7 to 1.5 μg/g; the analytes were separated in less than 6 min. The methodology proposed is useful for controlling and monitoring antibiotic residues in feedstuff samples.     

Development of a liquid chromatography tandem mass spectrometry method for simultaneous determination of eight adulterants in slimming functional foods

A method for simultaneous determination of eight adulterants including two appetite suppressants, two energy expenditure-enhancing drugs, one diuretic and three cathartics in slimming functional foods by high performance liquid chromatography with electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) was established. After samples were ultrasonically extracted with 70% (v/v) methanol aqueous solution and centrifuged, the components of ephedrine, norpseudoephedrine, fenfluramine, sibutramine, clopamide, emodin, rhein, and chrysophanol in sample solution were separated by a Hypersil Gold column (2.1 mm × 150 mm, 5 μm) using a programmed gradient elution. A mobile phase consisting of 0.02% (v/v) formic acid-ammonium formate buffer solution (pH=3.50) and methanol was used for elution with a flow rate set at 250 μL/min and column temperature of 25 °C. Qualitative determination was based on characteristic ion pairs and retention time of the targeted compounds using SRM (selective reaction monitoring) mode. Clenbuterol and ibuprofen were internal standards in positive and negative ionization mode, respectively. The internal standard curves were used for quantification measurement. The average recoveries of three different concentrations were from 80.2% to 94.5%. The limits of detection (LODs) were from 0.03 to 0.66 mg/kg (except chrysophanol 1.6 mg/kg). The linear dynamic range covered from 1 to 500 μg/L (except chrysophanol 50-5000 μg/L) for the twelve samples analyzed. Adulterants in four different kinds of slimming functional foods were determined by this developed method, and satisfactory results were obtained. These experimental results showed that, adulteration of sibutramine or/and fenfluramine were the major adulterating components with contents varying from 6.1 to 1.3×10(3) mg/kg and 1.9 to 9.7×10(3) mg/kg, respectively. In addition, three cathartic compounds were detected in six of those tested samples, and ephedrine, norpseudoephedrine and clopamide were not detected in all samples.     

Stability indicating method for the determination of paracetamol in its pharmaceutical preparations by TLC densitometric method

Simple, sensitive and accurate thin layer procedure was described for a quantitative determination of paracetamol in its bulk powder and in its pharmaceutical dosage forms in the presence of its degradation product. The method consists of dissolving the drug in methanol and then spotting the solution on a thin layer of silica gel G254. Paracetamol was separated on silica gel using the mixture of the mobile phase, ethyl acetate: benzene: acetic acid in a ratio (1:1:0.05 v/v/v).Absorbance measurements (detection of reflectance) of the separated drug were carried out at 250 nm. Calibration curves were established in the concentration range of 5–20 mcg/spot for paracetamol. Quantitation is achieved by comparing the area under the peaks obtained from scanning the thin layer chromatographic plates in a spectrodensitometer. The method has been successfully applied to pharmaceutical preparations (capsules) and the results obtained were statistically compared with those obtained by applying the reference method.     

Toxicological screening of human plasma by on‐line SPE‐HPLC‐DAD: identification and quantification of basic drugs and metabolites

An automated multi‐analyte screening method for the identification and quantification of 92 drugs and metabolites based on on‐line solid‐phase extraction–high‐performance liquid chromatography–diode array detection technique was developed and successfully validated. In addition, a database with 870 entries including UV‐spectra, relative/retention times and response factors of toxicologically relevant compounds was created. Plasma samples (0.2 mL) were treated with methanol, diluted with buffer and on‐line extracted (Strata X, 20 ×2 mm, 25 µm) at pH 9. Analytical separation was carried out on a Gemini NX column (150 ×4.6 mm, 3 µm) using gradient elution with acetonitrile–water (90:10,v/v) and 0.05 m potassium dihydrogen phosphate buffer (pH 2.3). Linear calibration curves with correlation coefficients ≥0.9950 were obtained for 78 analytes. As an additional benefit, the newly developed method allows the quantification of 42 analytes (e.g. antidepressants, neuroleptics and anticonvulsants) in a concentration range suitable for therapeutic drug monitoring. Limits of quantitation ranged from 0.02 mg/L (chlordiazepoxide) to 3.4 mg/L (mexiletine). Inter‐ and intra‐day precisions of quality control samples (low/high) were better than 15% (zolpidem) and accuracy (bias) ranged from ?11% (opipramol, venlafaxine) to 11% (venlafaxine, trazodone). Tests for carry‐over and sample stability under different storage conditions were also performed and stability was adequate. Four cases of poisoning analysis are presented. Copyright © 2014 John Wiley & Sons, Ltd.     

Enantioselective CE method for pharmacokinetic studies on ibuprofen and its chiral metabolites with reference to genetic polymorphism

A stereospecific CE method was elaborated for the quantification of ibuprofen enantiomers and their major phase I metabolites: 2'-hydroxy-ibuprofen and 2'-carboxy-ibuprofen in plasma and urine. Optimal temperature and pH of BGE were established to obtain complete separation of eight ibuprofen chiral compounds and (+)-S indobufen, applied as an internal standard, during one analytical run. After isolation from biological matrices using SPE on an octadecyl stationary phase, the analytes were separated and resolved up to 10 min in a silica capillary filled with BGE, consisting of heptakis 2,3,6-tri-O-methyl-beta-CD in triethanolamine-phosphate buffer, pH 5.0. Complete enantioseparation of the all analytes confirmed specificity of the method. The calibration curves were linear in the range of 0.1-25.0 mg/L for IBP enantiomers and their chiral metabolites in 0.5 mL of plasma and 1.0-200.0 mg/L in 0.05 mL of urine. Following SPE procedure, recovery of the chiral analytes from the two media was in the ranges of 82-87%, 90-95% and 70-76% for ibuprofen, 2'-hydroxy-ibuprofen and 2'-carboxy-ibuprofen enantiomers, respectively. The validated method was successfully applied in pharmacokinetic investigations of IBP enantiomers as well as free chiral metabolites in reference to the genetic polymorphism of CYP450 2C isoenzymes.     

Determination of methylamines and trimethylamine-N-oxide in particulate matter by non-suppressed ion chromatography

An ion chromatography method with non-suppressed conductivity detection was developed for the simultaneous determination of methylamines (methylamine, dimethylamine, trimethylamine) and trimethylamine-N-oxide in particulate matter air samples. The analytes were well separated by means of cation-exchange chromatography using a 3 mM nitric acid/3.5% acetonitrile (v/v) eluent solution and a Metrosep C 2 250 (250 mm × 4 mm i.d.) separation column. The effects of the different chromatographic parameters on the separation were also investigated. Detection limits of methylamine, dimethylamine, trimethylamine, and trimethylamine-N-oxide were 43, 46, 76 and 72 μg/L, respectively. The relative standard deviations of the retention times were between 0.42% and 1.14% while the recoveries were between 78.8% and 88.3%. The method is suitable for determining if methylamines and trimethylamine-N-oxide are a significant component of organic nitrogen aerosol in areas with high concentration of these species.     

Establishment and validation of an SIL-IS LC–MS/MS method for the determination of ibuprofen in human plasma and its pharmacokinetic study

In this work, we developed and validated a highly sensitive, rapid and stable LC–MS/MS method for the determination of ibuprofen in human plasma with ibuprofen-d3 as a stable isotopically labeled internal standard (SIL-IS). Human plasma samples were prepared by one-step protein precipitation. The chromatographic separation was achieved on a Poroshell 120 EC-C₁₈ (2.1 × 50 mm, 2.7 μm). Aqueous solution (containing 0.05% acetic acid and 5 mm NH₄Ac) and methanol were selected as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in negative ion mode. Multiple reaction monitoring mode was used for quantification using target fragment ions m/z 205.0 → 161.1 for ibuprofen and m/z 208.0 → 164.0 for SIL-IS, respectively. This method exhibited a linear range of 0.05–36 μg/ml for ibuprofen with correlation coefficient >0.99. Mean recoveries of ibuprofen in human plasma ranged from 78.4 to 80.9%. The RSD of intra- and inter-day precision were both < 5%. The accuracy was between 88.2 and 103.67%. The matrix effect was negligible in human plasma, including lipidemia and hemolytic plasma. A simple, efficient and accurate LC–MS/MS method was successfully established and applied to a pharmacokinetic study in healthy Chinese volunteers after a single oral administration of ibuprofen granules.     

Analysis of ibuprofen enantiomers in rat plasma by liquid chromatography with tandem mass spectrometry

A sensitive and selective method for the analysis of ibuprofen enantiomers by LC–MS/MS was developed and validated for the purpose of application in pharmacokinetic studies in small experimental animals. Aliquots of 200 μL plasma were submitted to liquid–liquid extraction with hexane/diisopropylether (50:50 v/v) in acid pH. Separation was accomplished in a Chirex® 3005 (250 × 4.6 mm, 5 μm) column at 25°C with a mobile phase that consisted of 0.01 M ammonium acetate in methanol at a flow rate of 1.1 mL/min. The mass spectrometer consisted of an ESI interface operating at negative ionization mode and multiple reaction monitoring. The transitions 205 > 161 and 240 > 197 were monitored for ibuprofen enantiomers and fenoprofen (internal standard), respectively. Method validation included the evaluation of the matrix effect, stability, linearity, lower LOQ, within‐run and between‐run precision, and accuracy. The lower LOQ was 25 ng/mL for each ibuprofen enantiomer, and the calibration curves showed good linearity in the range 0.025–50 μg/mL. The method was successfully applied in the investigation of pharmacokinetic disposition of ibuprofen enantiomers in rats treated orally with 25 mg/kg of the racemate. Enantioselective kinetic disposition was observed with accumulation of (+)‐(S)‐ibuprofen in rats following single oral administration.     

Determination of betaine, choline and trimethylamine in feed additive by ion-exchange liquid chromatography/non-suppressed conductivity detection

An ion chromatography method with non-suppressed conductivity detection was developed for the simultaneous determination of betaine, choline and trimethylamine in feed additive. The analytes and the common inorganic cations were well separated by means of cation-exchange chromatography using a 4.5 mmol/L methanesulfonic acid solution containing 10% (v/v) acetonitrile as eluent and an IonPac SCS1 column (250 mm x 4 mm i.d.) as the separation column. The effects of the different chromatographic parameters on the separation were also investigated. Detection limits of betaine, choline and trimethylamine were 0.076, 0.044 and 0.041 mg/L. The relative standard deviations (RSDs) of the retention time and peak area were less than 0.30% and 0.88%, respectively. The recoveries were between 93.2% and 112.6%. The method is suitable for use as a routine method in production quality control of feed additive.