固相萃取-离子色谱法测定饮用水中的痕量卤代乙酸

建立了固相萃取-离子色谱(SPE-IC)测定饮用水中痕量卤代乙酸(HAAs)(包括一氯乙酸、二氯乙酸、三氯乙酸、一溴乙酸和二溴乙酸)的方法。固相萃取采用LiChrolut EN SPE柱来进行痕量待测物的预浓缩（25倍）和基体杂质的消除,用NaOH(10 mmol/L)洗脱;色谱分离采用亲水性、高容量、氢氧化物选择型阴离子交换柱Dionex IonPac AS16(250 mm×4 mm i.d.),以NaOH为流动相进行浓度梯度淋洗,淋洗速度为0.8 mL/min,电导检测,进样量为500 μL。结果表明,用SPE-IC法测定HAAs,一溴乙酸的检测限为12.5 μg/L,其余4种HAAs的检测限为0.38~1.69　μg/L。该法可实现对饮用水中痕量卤代乙酸的测定。     

反相固相萃取/超高效液相色谱-串联四极杆质谱仪同时测定污水中9种卤乙酸的方法研究

使用反相固相萃取预处理与超高效液相色谱-串联四极杆质谱仪(RSPE UPLC-MS/MS)联用建立了同时测定污水中9种卤乙酸(HAAs)的分析方法。研究表明:ENVI-C18固相萃取小柱能有效去除污水样品中有机基质的干扰,样品pH值调至2.5能有效消除无机离子对HAAs离子化的影响;采用HSST3(2.1 mm×100 mm)色谱柱,以甲醇和0.000 5%甲酸为流动相,可在15.0 min内将9种HAAs分离且效果良好。采用优化后的程序建立标准曲线,9种HAAs的线性范围为0.5~100μg/L,相关系数(r2)为0.999 7~0.999 9,检出限和定量下限分别为0.02~0.26μg/L和0.05~0.86μg/L,日内和日间相对标准偏差分别为1.4%~10.0%和1.7%~10.0%。3个污水处理厂出水在2.5μg/L和10μg/L的加标浓度水平下,回收率为85.2%~107.8%。该方法能够满足污水处理厂出水中9种HAAs的检测要求。     

液-液萃取衍生气相色谱法测定饮用水中卤乙酸

建立了测定饮用水中5种卤乙酸的检测方法。水样经硫酸酸化、叔丁基甲醚萃取、硫酸-甲醇衍生化后,用气相色谱电子捕获检测器测定。5种卤乙酸平均加标回收率为74.5%~104.0%,相对标准偏差为3.1%~11.0%(n=6),最低检出限为0.3~15.3μg/L。该法适用于饮用水中卤乙酸的测定。     

固相微萃取-气相色谱-质谱法同时测定天然饮用水中39种有机污染物

提出了固相微萃取-气相色谱-质谱法测定天然饮用水中39种有机污染物含量的方法。为使固相微萃取达到更高的效率,选用60μm PDMS/DVB作为固相萃取头的涂层,萃取温度及时间为90℃和30min,解析温度及时间为270℃和10min。用J&W DB-35 MS毛细管色谱柱分离,电子轰击离子源选择离子监测模式检测。39种有机污染物的质量浓度均在0.10～50.0μg.L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.002～2μg.L-1之间。方法的回收率在82.0%～110%之间,测定值的相对标准偏差(n=6)在2.0%～13%之间。     

固相萃取-超高效液相色谱-三重四极杆质谱法测定饮用水中13种卤代苯醌类消毒副产物

卤代苯醌作为一类新检出的消毒副产物,在饮用水中检出率高但含量较低。为准确、高效、高通量分析饮用水中的卤代苯醌,本文基于固相萃取前处理和超高效液相色谱-三重四极杆质谱,建立了同时检测饮用水中13种卤代苯醌(6种氯代苯醌、6种溴代苯醌、1种碘代苯醌)的方法。在1 L水样中加入2.5 mL甲酸混匀,取500 mL水样经Plexa固相萃取柱(200 mg/6 mL)富集浓缩后,进行超高效液相色谱-三重四极杆质谱检测。以HSS T₃色谱柱(100 mm×2.1 mm, 1.8μm)分离,甲醇-0.1%甲酸水溶液为流动相进行梯度洗脱,采用电喷雾负离子模式电离、多反应监测模式检测,基质匹配外标法定量。以饮用水为基质考察方法的精密度和准确度,结果表明,13种卤代苯醌在各自的线性范围内呈现良好的线性关系,相关系数(r)均大于0.999,方法检出限(MDL,S/N=3)和方法定量限(MQL,S/N=10)分别为0.2～10.0 ng/L和0.6～33.0 ng/L。不同加标水平(10、20、50 ng/L)下13种卤代苯醌的回收率为56%～88%,相对标准偏差(RSD,n=6)均≤9...     

固相萃取/超高压液相色谱测定水中痕量呋喃丹、甲萘威及阿特拉津

建立了固相萃取/超高压液相色谱测定水中痕量呋喃丹、甲萘威和阿特拉津的分析方法。通过对色谱流动相和紫外检测条件、固萃小柱和上样速度、滤器材质等进行优化,确定了最佳实验方案。水样以5～10 mL/min的速度上样,采用Bond Elute Plexa固相萃取小柱富集,二氯甲烷洗脱。洗脱液经浓缩和重溶后,过尼龙滤膜,采用超高压液相色谱分析,色谱柱为ACQUITY UPLC BEH C18(2.1 mm×50 mm,1.7μm),流动相为甲醇-水(55∶45),检测波长为222 nm,流速为0.4 mL/min。在优化条件下,1.5 min内可对3种化合物实现基线分离。呋喃丹、甲萘威和阿特拉津在0.1～2.0 mg/L范围内的线性系数均大于0.999,其仪器精密度(n=9)分别为1.7%、0.2%和0.7%,方法检出限(S/N=3)分别为0.04、0.003、0.004μg/L。在高、低水平加标浓度下,方法回收率为74%～94%。该方法具有分析速度快、操作简单和检出限低等优点,可用于同时分析水体中痕量的呋喃丹、甲萘威和阿特拉津。     

固相萃取-液质联用法同时测定水中的喹诺酮类和磺胺类抗生素

建立了固相萃取-超高效液相色谱三重四级杆质谱联用法同时测定水中痕量的5种喹诺酮类和6种磺胺类抗生素残留的方法,水样经过固相萃取富集后由液相色谱分离、三重四级杆质谱检测。该方法在8 min内完成对11种目标化合物的分析。喹诺酮类抗生素线性范围为0.5～50μg/L,磺胺类抗生素线性范围为1～100μg/L,相关系数均大于0.995,6次空白加标重复测定的相对标准偏差(n=6)为喹诺酮类抗生素5.3%～9.0%,磺胺类抗生素4.7%～10.2%。11种目标化合物的方法检出限在0.04～0.22 ng/L之间,实际样品的加标回收率为62.1%～137%。该方法操作简便,重现性好,可用于地表水中抗生素的检测。     

基于溶胶凝胶技术的在线固相萃取与高效液相色谱联用测定饮用水中的雌激素残留

建立了固相萃取与高效液相色谱在线联用测定水样中3种雌激素(己烯雌酚、己烷雌酚、双烯雌酚)痕量残留的方法。以溶胶凝胶技术合成的聚合物为固相萃取材料,对水样中的雌激素进行萃取富集,考察了样品溶液不同pH、上样流速及洗脱溶剂等条件对合成材料富集效果的影响。结果表明,在优化的条件下,该方法对3种雌激素的检出限(S/N=3)为0.07~0.13 μg/L,样品中的加标回收率为82.31%~99.43%,相对标准偏差(RSD)为1.61%~7.15%。方法简便可靠,适用于饮用水中雌激素的痕量残留检测。     

液相色谱-串联质谱法快速测定粮谷中矮壮素和敌草快残留量

提出了粮谷中矮壮素和敌草快的液相色谱-串联质谱分析方法。样品经甲醇-水-乙酸溶液提取后,经HLB固相萃取小柱净化,以Water ACOUITY UPLC BEH C18色谱柱为分离柱,0.1%(体积分数)甲酸-乙腈(20+80)混合溶液为流动相,采用正离子模式监测。矮壮素和敌草快的线性范围均为5.00～500μg.L-1,检出限(3S/N)分别为2.5,5.0μg.kg-1。回收率分别在77.7%～93.1%,73.9%～95.3%之间;测定值的相对标准偏差(n=7)均小于15%。     

GC-ECD法快速测定饮用水中卤乙酸的方法研究

通过优化卤乙酸衍生化条件、改进色谱条件，建立了一种利用短程色谱柱快速测 定饮用水中5种卤乙酸的GC-ECD方法。方法的特点是色谱程序简单、运行时间短，色谱运行时间仅为10．8min，远少于通常的运行时间。方法的检出限较低，精密度较好，除MCAA外，MBAA、DCAA、TCAA和DBAA的检出限和相对标准偏差分别小于0．46μg／L和4％（n=7）；5种卤乙酸的加标回收率在86．6％～109．3％之间，满足EPA 6251B标准方法的要求。     

Comparison of Different Cartridges of Solid Phase Extraction for Determination of Polyphenols in Tobacco by UPLC/MS/MS and Multivariate Analysis

The comparison of solid phase extraction(SPE) for the preconcentration and isolation of polyphenols in tobacco samples was carried out by ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) and multivariate analysis.Several adsorbing materials of SPE(C18,NH2,SAX and OASIS) were investigated.It was found that the C18 and OASIS cartridges can not only speed up the purification process,but also simplify the SPE operation.A UPLC/MS/MS was used for the determination of polyphenols ...     

Validation of a method for the determination of chloramphenicol in poultry and swine liver by ultra-performance liquid chromatography coupled with tandem mass spectrometry

A sensitive and reliable method has been developed and validated for the determination of chloramphenicol in poultry and swine liver using SPE and ultra-performance liquid chromatography (UPLC)/MS/MS. The liver samples were extracted with ethyl acetate, defatted with n-hexane, and further cleaned up using SPE cartridges with polymeric sorbent. An Acquity BEH C18 column was used for gradient UPLC separation, with water and acetonitrile as the mobile phase. The multiple reaction monitoring mode was used for two precursor-product ion transitions for chloramphenicol and one for the internal standard. The method was validated at 0.1, 0.3, and 1.0 microg/kg. Mean recoveries from fortified samples ranged from 95.5 to 106.7% with an RSD of 12.2%. The method LOD was < 0.02 microg/kg.     

A broad-spectrum equine urine screening method for free and enzyme-hydrolysed conjugated drugs with ultra performance liquid chromatography/tandem mass spectrometry

The authors' laboratory at one time employed four liquid chromatography/mass spectrometric (LC/MS) methods for the detection of a large variety of drugs in equine urine. Drug classes covered by these methods included anti-diabetics, anti-ulcers, cyclooxygenase-2 (COX-2) inhibitors, sedatives, corticosteroids, anabolic steroids, sulfur diuretics, xanthines, etc. With the objective to reduce labour and instrumental workload, a new ultra performance liquid chromatography/tandem mass spectrometric (UPLC/MS/MS) method has been developed, which encompasses all target analytes detected by the original four LC/MS methods. The new method has better detection limits than the superseded methods. In addition, it covers new target analytes that could not be adequately detected by the four LC/MS methods. The new method involves solid-phase extraction (SPE) of two aliquots of equine urine using two Abs Elut Nexus cartridges. One aliquot of the urine sample is treated with β-glucuronidase before subjecting to SPE. A second aliquot of the same urine sample is processed directly using another SPE cartridge, so that drugs that are prone to decomposition during enzyme hydrolysis can be preserved. The combined eluate is analysed by UPLC/MS/MS using alternating positive and negative electrospray ionisation in the selected-reaction-monitoring mode. Exceptional chromatographic separation is achieved using an UPLC system equipped with a UPLC(?) BEH C18 column (10 cm L×2.1 mm ID with 1.7 μm particles). With this newly developed UPLC/MS/MS method, the simultaneous detection of 140 drugs at ppb to sub-ppb levels in equine urine can be achieved in less than 13 min inclusive of post-run equilibration. Matrix interference for the selected transitions at the expected retention times is minimised by the excellent UPLC chromatographic separation. The method has been validated for recovery and precision, and is being used regularly in the authors' laboratory as an important component of the array of screening methods for doping control analyses of equine urine samples.     

On-line coupling of solid-phase extraction with mass spectrometry for the analysis of biological samples. II. Determination of clenbuterol in urine using multiple-stage mass spectrometry in an ion-trap mass spectrometer

Solid-phase extraction (SPE) was coupled to ion-trap mass spectrometry to determine clenbuterol in urine. For SPE a cartridge exchanger was used and, after extraction, the eluate was directly introduced into the mass spectrometer. For two types of cartridges, i.e. C18 and polydivinylbenzene (PDVB), the total SPE procedure (including injection of 1 mL urine, washing, and desorption) has been optimised. The total analysis, including SPE, elution, and detection, took 8.5 min with PDVB cartridges, while an analysis time of 11.5 min was obtained with C18 cartridges. A considerable amount of matrix was present after extraction of urine over C18 cartridges, resulting in significant ion suppression. With PDVB cartridges, the matrix was less prominent, and less ion suppression was observed. For single MS, a detection limit (LOD) of about 25 ng/mL was found with PDVB cartridges. With C18 cartridges an LOD of only about 50 ng/mL could be obtained. Applying tandem mass spectrometry (MS/MS) did not lead to an improved LOD due to an interfering compound. However, a considerable improvement in the LOD was obtained with MS3. The selectivity and sensitivity were increased by the combination of efficient fragmentation of clenbuterol and reduction of the noise. Detection limits of 2 and 0.5 ng/mL were obtained with C18 and PDVB cartridges, respectively. The ion suppression was 4 to 45% (concentration range: 250 to 1.0 ng/mL) after extraction of urine using PDVB cartridges, and up to 70% ion suppression was observed using C18 cartridges. With MS4, no further improvement in selectivity and sensitivity was achieved, due to inefficient fragmentation of clenbuterol and no further reduction of noise.     

Re-usability of solid-phase extraction columns during the HPLC analysis of some macrolide antibiotics in serum and urine

Summary The re-usability of C₁₈ solid-phase extraction (SPE) cartidges was assessed utilizing two different analytical procedures developed for the analysis of erythromycin and josamycin in human serum and urine. A statistical procedure using confidence intervals was employed in order to determine a 10% change in drug recovery on re-use with a 95% degree of certainty. The results obtained indicated that the SPE cartridges could be successfully re-used up to three times for serum and urine samples containing physiological concentrations of erythromycin base and propionate. However, in the case of josamycin, results were inconsistent after the second re-use of the extraction cartridges for serum samples. Reproducible results, however, were still obtained for urine samples using the same SPE cartridges up to four times. The results indicate that although succesful re-use of SPE cartridges is possible, each drug and associated extraction conditions need to be carefully assessed prior to implementing such re-use.     

Solid-phase extraction of soy isoflavones

An automated method using solid-phase extraction (SPE) for the concentration and clean-up of soy isoflavone extracts is proposed in this work. Using a standardized sample (0.1 g of a freeze dried soybean extract/25 mL of water); eight SPE cartridges with a wide range of sorbents (C18, divinylbenzene and modified divinylbenzene) from different suppliers were evaluated and compared. A large variation on SPE cartridges performance was observed, especially regarding retention and breakthrough volume of isoflavones during sample load and washing steps. The most effective cartridges were the divinylbenzene based cartridges, especially Strata X (from Phenomenex) and HLB oasis (from Waters). Using Strata X cartridges, several extraction parameters, such as sample loading flow (5-15 mL min(-1)), extracting solvent volume (2-6 mL of methanol), pH of the extracting solvent and the necessity of drying the sorbent before elution, were evaluated to provide a fast, specific, quantitative and reproducible SPE method. The optimized method consists of conditioning the cartridge with 10 mL of methanol and 10 mL of water (10 mL min(-1)), loading 25 mL of the standardized extract onto the cartridges (5 mL min(-1)), washing the cartridge with 10 mL of water (10 mL min(-1)) and finally eluting with 4 mL of methanol (10 mL min(-1)). Mean isoflavones recovery was 99.37% and mean intra- and inter-day reproducibility was higher than 98%. The developed sample clean-up/concentration (6.25:1) method takes less than 10 min and can be used in the analysis of isoflavones from soy extracts.     

Electric Field-Assisted Solid Phase Extraction: Devices, Development and Application with a Cationic Model Compound

This work describes novel devices for electric field-assisted solid phase extraction (E-SPE) and an application was carried out on the antimicrobial marbofloxacin (MAR). Conventional syringe-type SPE cartridges were easily adapted to receive two electrodes that were inserted and positioned below and above the sorbent. The adapted cartridges were coupled to a flow extraction system, which consisted of an electrophoresis power supply, a peristaltic pump and a homemade SPE manifold. These devices were used to apply electric fields during the extraction of MAR from fortified buffer and milk samples. The recovery of MAR was improved (2.3 times) or reduced (4.2 times) in comparison to conventional SPE when the top electrode was used as cathode (E-SPE_(?/+)) or anode (E-SPE_(+/?)), respectively. The results demonstrated that usual SPE cartridges can be easily and inexpensively adapted for applying an electric field in SPE. It was also concluded that the electric field applied in a usual SPE cartridge can be employed as a new suitable approach to enhance the extraction efficiency of ionic compounds in a complex sample matrix.     

Characterization of molecularly imprinted polymers for the extraction of tobacco alkaloids and their metabolites in human urine

Molecularly imprinted polymers (MIPs) are synthetic polymers designed to selectively extract target analytes from complex matrices (including biological matrices). The literature shows that MIPs have a degree of cross-selectivity from analytes within the same class of compounds. A commercially available MIP for tobacco-specific nitrosamines (TSNAs) is designed to be class selective for four TSNA compounds. This study sought to characterize the extent of cross-selectivity of the TSNA MIPs with other tobacco alkaloids. Cross-selectivity and recovery of the SupelMIP™ TSNA SPE cartridges was assessed with N-nitrosonornicotine (NNN), nicotine, cotinine and morphine. Their recoveries were compared with the recoveries of a nonimprinted polymer SPE cartridge, and two traditional SPE cartridges: a Waters mixed-mode cation exchange cartridge and a Waters hydrophilic–lipophilic balance cartridge. NNN and cotinine had the highest recoveries with the MIP cartridge, over 80%, and cotinine samples in urine had >80% recoveries. Nicotine had highly variable recoveries, possibly owing to differing chemical properties from the TSNAs. All three analytes had significantly different recoveries with the MIP cartridges compared with the traditional SPE cartridges. Morphine displayed nonspecific interactions with the MIP cartridges. Utilization of the TSNAs’ cross-selectivity allows for simultaneous extraction and identification of multiple tobacco biomarkers using one extraction technique.     

Inter-laboratory comparison of liquid chromatographic techniques and enzyme-linked immunosorbent assay for the determination of surfactants in wastewaters

Seven laboratories participated in an inter-laboratory comparison exercise within the framework of the PRISTINE, SANDRINE and INEXsPORT European Union Projects. Solid-phase extraction (SPE) methodologies were used for the extraction of target analytes from wastewaters. The analytical strategies were based on liquid chromatography (LC) coupled to mass spectrometric (MS) or to fluorescent (FL) detection in all cases with the exception of one laboratory using a test-tube enzyme-linked immunosorbent assay kit. Samples were spiked with the surfactants nonylphenolpolyglycol ether, coconut diethanolamide, linear alkylbenzene sulfonate, nonylphenolpolyglycol ether sulfate, alkylpolyglycol ether and secondary alkane sulfonate. After enrichment on previously conditioned SPE cartridges, the SPE cartridges were distributed among the participating laboratories without the information about the amount of spiked surfactants. In addition, SPE cartridges loaded with a real-world environmental sample containing a tannery wastewater were also analyzed. The results of the programme showed that SPE followed by LC-MS techniques are reliable for the surfactants determination at submicrogram to microgram per liter levels in wastewaters. Inter-laboratory precision values were calculated as the reproducibility relative standard deviation (RSD(R)) which was determined from the reproducibility standard deviation (sR) and the average concentration at a particular concentration level. When data from all laboratories were pooled, the RSD(R) values ranged from 5.1 to 28.3% for the determination of target analytes. The most accurate result corresponded to that given for linear alkylbenzene sulfonates. Taking into account that different methodologies were used (including non-chromatographic techniques) and the complexity of the samples analyzed, it can be considered that acceptable reproducibility values were obtained in this inter-laboratory study.     

Fast liquid chromatography–quadrupole-linear ion trap mass spectrometry for the analysis of pharmaceuticals and hormones in water resources

This paper presents the development of a fast multi-residue method for the determination of 49 pharmaceuticals and 6 metabolites from different therapeutic classes in water resources by means of Ultra-performance™ liquid chromatography (UPLC) coupled to tandem mass spectrometry. The use of the UPLC technology enabled all the 55 compounds to be separated chromatographically in less than 9 min (6.3 min positive mode and 2.7 min negative mode) and with a total analysis time of 18 min when considering column conditioning. Improved resolution, sensitivity and a reduction of matrix effects were obtained under these conditions. Unequivocal identification and quantification of the target compounds was also performed by using the dual acquisition modes of the hybrid triple quadrupole-linear ion trap (QqLIT) system. Triple quadrupole mode by means of selected reaction monitoring (SRM) was used for quantification, whilst a second SRM transition together with information-dependent analysis (IDA) experiments was used for confirmation. Additionally, one general, single solid-phase extraction (SPE) method was developed by using Oasis HLB cartridges. Quality parameters of the method in wastewaters were established obtaining a fast, robust, reproducible and cost-effective method for all the target pharmaceuticals. Finally, the optimized SPE-UPLC/QqLIT method was used for the analysis of the target compounds in wastewaters from Spain. Thirty-one out of fifty-five compounds were identified in the samples collected.