Determination of estrogenic steroids in surface water and wastewater by liquid chromatography-electrospray tandem mass spectrometry

An analytical method is presented which permits trace level determination of 17alpha-ethynylestradiol (EE2), 17beta-estradiol (E2), and estrone (E1). Using this method, the estrogenic steroids were analyzed in drinking water, surface water, and wastewater (sewage influents and effluents) at concentrations down to 0.1 ng/L. Sample volumes between 100 and 500 mL are concentrated using automated solid-phase extraction. Analysis is performed by liquid chromatography with detection by tandem mass spectrometry. Applying simple clean-up procedures and internal standard calibration, recovery losses resulting from matrix-dependent ion suppression during electrospray ionization could be compensated for all of the investigated compounds. Recoveries around 100% were obtained for all analytes after correction using the internal standards. Limits of quantification (LOQ) were between 0.1 and 0.4 ng/L for purified sewage, surface, ground, and drinking water and between 1 and 2 ng/L in the case of raw sewage. Water treatment by wastewater treatment plants (WWTPs) or by a surface water treatment plant affected the removal of all estrogenic steroids. Thus, E1, E2, and EE2 were removed in the municipal WWTPs to the extent of 93%, 93%, and 80%, respectively. In the effluents of the WWTP in Ruhleben (Berlin, Germany), E1, E2, and EE2 were detected at the low ng/L level. E2 and EE2 were, however, not present in the Berlin surface water above the LOQ (0.2 ng/L). E1 was the only compound that could be detected in surface water samples. After additional surface water treatment it was still detectable but only at trace-level concentrations with a mean value of 0.16 ng/L.     

Determination of abamectin and azadirachtin residues in orange samples by liquid chromatography-electrospray tandem mass spectrometry

A rapid and sensitive LC-ESI-MS-MS method has been developed for the determination of azadirachtin and abamectin residues in orange samples. Samples were extracted with acetonitrile, in a high-speed blender. After the addition of sodium acetate, an aliquot of extract was directly injected into the LC-ESI-MS-MS system. The highest sensitivity of the method was achieved under MS-MS conditions using [M+Na]+ adducts as precursor ions. Recoveries for both compoundsfrom spiked orange samples at 0.01 and 0.1 mg/kg were above 80%, with good repeatability (<10%). Method detection limits achieved (<0.007 mg/kg) were adequate for the determination of these pesticides in this kind of sample from the regulatory point of view. The importance of the solvent used for extraction, as well as the addition of sodium acetate to the extracts and the selection of adequate chromatographic conditions are discussed.     

Determination of perfluorinated compounds in wastewater and river water samples by mixed hemimicelle-based solid-phase extraction before liquid chromatography-electrospray tandem mass spectrometry detection

A comparative study on the use of cetyltrimethylammonium bromide (CTAB)-coated silica and sodium dodecyl sulphate (SDS)-coated alumina mixed hemimicelles-based solid-phase extraction (SPE) for the pre-concentration of six perfluorinated compounds (PFCs) in environmental water samples was presented. The six analytes heptafluorobutyric acid (HFBA), perfluoroheptanic acid (PFHeA), perfluorooctanic acid (PFOA), perfluorooctanic sulfonic (PFOS), perfluorononanic acid (PFNA) and perfluorodecanic acid (PFDeA) were quantitatively retained on both sorbent materials. The cationic surfactant (CTAB adsorbed onto silica) was more appropriate for SPE of PFCs. The main factors affecting adsolubilization of PFCs including the amount of surfactant, pH of solution, sample loading volume and desorption were investigated and optimized. Concentration factor of 500 were achieved by SPE of 500 mL of several environmental water samples. The method detection limits obtained for HFBA, PFHeA, PFOA, PFOS, PFNA and PFDeA were 0.10, 0.28, 0.07, 0.20, 0.10 and 0.05 ng/L, respectively. The relative standard deviation of recoveries ranged from 2 to 8%, which indicated good method precision.     

Determination of oxatomide in human plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry

A rapid, sensitive and specific high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the determination of oxatomide in human plasma. Flunarizine hydrochloride was employed as the internal standard (IS). The analytes were chromatographically separated on a Shimadzu Shim-pack VP-ODS C18 column (250 x 2.0 mm i.d.) with a mobile phase consisting of methanol and aqueous ammonium acetate solution (10 mm, pH 4.0; 85:15, v/v). Detection was performed on a single quadrupole mass spectrometer using an electrospray ionization interface with the selected-ion monitoring (SIM) mode. The method showed excellent linearity (r = 0.9995) over the concentration range of 0.5-500 ng/mL with good accuracy and precision. The intra- and inter-batch precisions were within 10% relative standard deviation. The recoveries were more than 90%. The validated method was successfully applied to a preliminary pharmacokinetic study of oxatomide in Chinese healthy male volunteers.     

Determination of tridemorph and other fungicide residues in fruit samples by liquid chromatography-electrospray tandem mass spectrometry

A rapid and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) method for the determination of tridemorph and other pre- and post-harvest fungicides (carbendazim, thiabendazole, imazalil, propiconazole and bitertanol) in banana and orange samples has been developed and validated. The sample preparation was a simple extraction step with acetone using a high-speed blender prior to the injection of the five-fold diluted extract into the LC system with no other previous sample pre-treatment. Quantification was carried out using a matrix matched calibration curve which was linear in the range of 1-100 ng ml(-1) for all the compounds. The limit of quantification was 0.05 mg kg(-1) for all studied compounds, whereas limits of detection ranged between 0.005 and 0.025 mg kg(-1) (0.01 mg kg(-1) for tridemorph). Recoveries for tridemorph from spiked banana and orange samples at 0.05 and 1 mg kg(-1) were satisfactory, with values between 83 and 99% and relative standard deviations (R.S.D.s) lower than 13% (n = 5). For the other fungicides, recoveries between 75 and 95% with R.S.D.s lower than 12% were obtained. The developed method has been applied to the determination of selected fungicides in real samples of bananas and oranges from different origin. Thiabendazole and imazalil have been detected in almost all orange samples analyzed, and in around of 30% of banana samples. Bitertanol residues exceeded the maximum residue level (0.05 mg kg(-1)) in three banana samples while tridemorph was only detected in one sample.     

离子色谱-质谱联用技术测定饮用水及环境水样中的痕量高氯酸盐

建立了一种测定痕量高氯酸盐的离子色谱-质谱联用方法.选用高容量、强亲水性的阴离子交换柱IonPac AS20(2 mm)进行分离,以淋洗液自动发生器在线产生的KOH为淋洗液,采用等浓度淋洗.在不添加有机溶剂的情况下,淋洗液经过抑制器抑制后直接进入电喷雾-串联质谱(ESI-MS-MS),以负离子模式进行检测.同时采用多元反应监测(MRM)模式对高氯酸盐进行监控,以100.8/84.9、 98.8/66.9和100.8/68.9为监控离子对,以98.8/82.9离子对的峰面积进行定量.高氯酸盐质量浓度在0.05～50 μg/L范围内具有良好的线性(r＝0.9985),检出限(S/N=3)为0.01 μg/L.将该方法用于饮用水以及地下水、雪水等环境水样中高氯酸盐的分析,并进行了加标回收实验,回收率在86%～110%之间,将实际自来水样品连续11次进样,所得高氯酸盐的峰面积的相对标准偏差(RSD)为1.6%.     

高效液相色谱-电喷雾串联质谱法检测环境水样中22种抗生素类药物

建立了高效液相色谱-电喷雾串联质谱(HPLC-ESI MS/MS)分析环境水样中22种抗生素类药物的方法。采用HLB固相萃取柱对环境水样中的目标化合物进行富集、净化,然后以6 mL氨水-甲醇(5:95, v/v)溶液洗脱。收集的洗脱液经氮气吹干至1 mL,然后进行HPLC-ESI MS/MS分离分析。色谱流动相A相为甲醇-乙腈(1:1, v/v), B相为0.3%(体积分数)甲酸水溶液(含0.1%(体积分数)甲酸铵,pH 2.9);色谱柱为XTerra MS C18柱。质谱检测采用正离子扫描,多反应监测模式。分别以自来水和污水作为基质,22种抗生素类药物的加标平均回收率分别为54.9%～130%和57.4%～138%,相对标准偏差(n=3)分别为2.85%～28.6%和2.02%～23.2%;方法的检出限为0.05～0.5 ng/L。将建立的方法应用于北京市高碑店湖和小清河水样的分析,结果表明在两个水样中均有部分抗生素类药物检出。     

Determination of carnitine and acylcarnitines in urine by high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometry

A high-performance liquid chromatography-mass spectrometry method has been developed for the simultaneous determination of native carnitine and eight acylcarnitines in urine. The procedure uses a solid-phase extraction on a cation-exchange column and the separation is performed without derivatization within 17 min on a reversed-phase C8 column in the presence of a volatile ion-pairing reagent. The detector was an ion trap mass spectrometer and quantification was carried out in the MS-MS mode. Validation was done for aqueous standards at ranges between 0.75 and 200 micromol/l, depending on the compound. Carnitine was quantified in urine and comparison with a radioenzymatic assay gave a satisfactory correlation (R2 = 0.981). The assay could be successfully applied to the diagnostic of pathological acylcarnitines profile of metabolic disorders in urines of patients suffering from different organic acidurias.     

Determination of quaternary ammonium pesticides by liquid chromatography-electrospray tandem mass spectrometry

A method for the direct determination of paraquat, diquat, chlormequat and difenzoquat in water samples, using an on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry system was developed. No sample preparation was required and the detection limits were below the European Union maximum residue levels. The chromatographic separation was performed using an XTera MS C8 column. The concentration of the ion pair reagent, the pH and the gradient elution were optimized to give high recoveries and good chromatographic resolution between quats. The detection was carried out using an ion trap as mass analyzer. Parameters such as the magnitude and duration of the resonant excitation voltage and the magnitude of the trapping RF voltage for full scan tandem mass spectrometry (MS-MS) experiments were studied to establish the optimal experimental conditions. Moreover, the accurate optimization of these parameters allowed MS-MS experiments of low mass ions, below m/z 200, providing unambiguous peak identification. Finally, the reproducibility of the proposed method was shown by good run-to-run and day-to-day precision values and its applicability to the determination of quats in drinking water was evaluated using spiked samples.     

超高效液相色谱-电喷雾串联质谱法同时测定地表水中28种皮质激素

建立了同时测定地表水中28种皮质激素的超高效液相色谱-电喷雾串联质谱（UHPLC-ESI-MS/MS）的分析方法。水样经HLB柱固相萃取、C₈反相色谱柱分离,在动态多反应监测（DMRM）模式下采用电喷雾离子化正、负离子模式（ESI±）进行信号采集与测定,内标法定量。结果发现,28种皮质激素在1.0~100 μg/L范围内具有良好的线性关系（R²>0.99）,方法检出限为0.21~0.48 ng/L,方法定量限为0.32~0.72 ng/L。在5.0、10、50 ng/L的基质加标水平下,28种目标物的平均回收率为68.8%~108.7%,相对标准偏差为0.1%~8.1%。该方法灵敏、准确、可靠,将广泛应用于环境中糖/盐皮质激素的痕量监测及其行为、风险研究。     

Determination of sertraline in human plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry and method validation

A sensitive, simple, and specific liquid chromatographic method coupled with electrospray ionization-mass spectrometry (MS) is presented for the determination of sertraline in plasma. With zaleplon as the internal standard, sertraline is extracted from the alkalized plasma with cyclohexane. The organic layer is evaporated and the residue is redissolved in the mobile phase of methanol-10 mmol/L ammonium acetate solution-acetonitrile (62:28:10, v/v/v). An aliquot of 20 microL is chromatographically analyzed on a Shimadzu ODS C18 column (5 microm, 150- x 4.6-mm i.d.) by means of selected-ion monitoring mode of MS. The calibration curve of sertraline in plasma exhibits a linear range from 0.5 to 25.0 ng/mL with a correlation coefficient of 0.9998. The limit of quantitation is 0.5 ng/mL. The intra- and interday variations (relative standard deviation) are less than 7.8% and 9.5% (n = 5), respectively. The application of this method is demonstrated for the analysis of sertraline plasma samples in a human pharmacokinetic study.     

Determination of perfluorinated compounds in environmental water samples by high-performance liquid chromatography-electrospray tandem mass spectrometry using surfactant-coated Fe3O4 magnetic nanoparticles as adsorbents

A novel method was developed for solid-phase extraction (SPE) of perfluorinated compounds (PFCs) from environmental water samples using cetyltrimethylammonium bromide (CTAB) coated Fe₃O₄ nanoparticles (Fe₃O₄ NPs) as an adsorbent. The magnetic nanosized adsorbent has a large surface area and superparamagnetic properties. This gives it a high extraction capacity and allows for convenient isolation by a magnetic field. Compared with other SPE methods and our previous work on PFCs, this method exhibited a fairly good analytical performance and required a small amount of sorbent (50 mg) and short pretreatment times (30 min) for 800 mL environmental water samples. Seven PFCs, including perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and perfluorotetradecanoic acid (PFTA), extracted by the optimized method were determined by high-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC/ESI-MS/MS). A concentration factor of 1600 was achieved when extracting 800 mL of several environmental water samples. Detection limits obtained for PFOA, PFOS, PFNA, PFDA, PFUnDA, PFDoDA and PFTA were 0.14, 0.022, 0.31, 0.23, 0.11, 0.16, 0.091 ng/L, respectively. The relative standard deviations of recoveries ranged from 1 to 8%, indicating good method precision.     

超高效液相色谱-电喷雾电离串联质谱联用法检测茶叶中阿维菌素类药物残留

建立了采用超高效液相色谱-电喷雾电离串联质谱同时检测茶叶中爱比菌素、甲胺基阿维菌素、乙酰胺基阿维菌素、伊维菌素、多拉菌素、莫西丁克残留的方法。试样经饱和氯化钠溶液浸润后,用乙腈提取,C18固相萃取小柱净化,超高效液相色谱-电喷雾串联质谱法(UPLC/ESI-MS/MS)测定。对流动相、监测离子、校正曲线等进行了优化和探讨。6种分析物在2.0～50 μg/L范围内线性关系良好,相关系数均大于0.9920。莫西丁克在5,10,20 μg/kg,其余分析物在2,5,10 μg/kg加标水平的平均回收率为61.7%～85.4%,相对标准偏差为9.37%～17.19%。该方法可靠、稳定,可满足茶叶中阿维菌素类药物残留检测与确证的需要。     

Trace analysis of 28 steroids in surface water, wastewater and sludge samples by rapid resolution liquid chromatography-electrospray ionization tandem mass spectrometry

A sensitive rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS) method, combined with solid-phase extraction, ultrasonic extraction and silica gel cartridge cleanup, was developed for 28 steroids including 4 estrogens (estrone (E1), 17β-estradiol (E2), 17α-ethynyl estradiol (EE2), diethylstilbestrol (DES)), 14 androgens (androsta-1,4-diene-3,17-dione (ADD), 17α-trenbolone, 17β-trenbolone, 4-androstene-3,17-dione, 19-nortestoserone, 17β-boldenone, 17α-boldenone, testosterone (T), epi-androsterone (EADR), methyltestosterone (MT), 4-hydroxy-androst-4-ene-17-dione (4-OHA), 5α-dihydrotestosterone (5α-DHT), androsterone (ADR), stanozolol (S)), 5 progestagens (progesterone (P), ethynyl testosterone (ET), 19-norethindrone, norgestrel, medroxyprogesterone (MP)), and 5 glucocorticoids (cortisol, cortisone, prednisone, prednisolone, dexamethasone) in surface water, wastewater and sludge samples. The recoveries of surface water, influents, effluents and sludge samples were 90.6-119.0% (except 5α-DHT was 143%), 44.0-200%, 60.7-123% and 62.6-138%, respectively. The method detection limits for the 28 analytes in surface water, influents, effluents and freeze-dried sludge samples were 0.01-0.24 ng/L, 0.02-1.44 ng/L, 0.01-0.49 ng/L and 0.08-2.06 ng/g, respectively. This method was applied in the determination of the residual steroidal hormones in two surface water of Danshui River, 12 wastewater and 8 sludge samples from two wastewater treatment plants (Meihu and Huiyang WWTPs) in Guangdong (China). Ten analytes were detected in surface water samples with concentrations ranging between 0.4 ng/L (17β-boldenone) and 55.3 ng/L (5α-DHT); twenty analytes in the wastewater samples with concentrations ranging between 0.3 ng/L (P) and 621 ng/L (5α-DHT); and 12 analytes in the sludge samples with concentrations ranging between 1.6 ng/g (E1) and 372 ng/g (EADR).     

液相色谱-电喷雾串联质谱法测定冬青芽中的脱落酸

建立了测定植物中痕量脱落酸 (ABA) 的液相色谱-电喷雾串联质谱联用分析方法. 植物提取液先采用固相萃取 (SPE) 富集脱落酸并消除基体干扰, 然后以C18柱为固定相, V(甲醇)∶V(2 g/L甲酸水溶液)＝50∶50为流动相分离脱落酸. 电喷雾(ESI)串联质谱采用负离子模式. 选择反应监测 (SRM) 模式用于脱落酸定量, 选择的离子对是263→153, 219. 脱落酸的线性范围为0.005～10 μg/mL, 检测限 (S/N=3) 为0.003 μg/mL, 加标0.02 μg和0.05 μg的回收率分别为98.3% 和103.5%. 该方法用于冬青芽中脱落酸的分析, 结果表明所建立的SPE-LC-MS/MS方法对于分析植物中的痕量脱落酸是有效的.     

LC/MS法分析头孢替坦二钠原料中的杂质

本文应用LC/MS技术对头孢替坦二钠原料中的4种杂质进行了快速鉴定.根据头孢菌素的降解反应机制设计加速实验,确定头孢替坦的2个主要杂质为其碱水解产物;以1%冰醋酸溶液-乙腈-甲醇为流动相,经C18柱分离,通过电喷雾串联质谱负离子检测,获得各杂质的相对分子质量信息和碎片信息,并辅助UV特征对杂质结构进行了鉴定.在所建立的LC/MS条件下,头孢替坦及其杂质得到有效的分离,4个杂质经分析分别为5-巯基-1-甲基-四氮唑、头孢替坦内酯、头孢替坦脱羧物和头孢替坦异构体.本研究表明,利用LC/MS技术可推测头孢菌素类抗生素中杂质的结构,且本方法快速、灵敏、专属性高.     

超高效液相色谱-电喷雾串联质谱法测定生活饮用水中49种药物及5种代谢物

建立了超高效液相色谱-电喷雾串联质谱(UPLC-ESI MS/MS)分析生活饮用水中54种药物的方法。采用HLB固相萃取柱对水样中的目标化合物进行富集净化,以5 mL甲醇洗脱;洗脱液用氮气吹至近干,用0.4 mL 0.1%甲酸水溶液定容,上机分析;ACQUITY UPLC^TMBEH C₁₈柱用作色谱分离,以0.1%甲酸水溶液-甲醇为流动相进行梯度洗脱;多反应监测(MRM)模式进行检测;目标药物使用基质外标法定量。54种药物在自备井水、市政末梢水和地表水中的加标回收率分别为58.7%~104.4%、53.1%~109.5%和50.7%~118.8%,相对标准偏差(n=6)分别为0.3%~12.8%、1.0%~15.5%和0.4%~19.3%;方法定量限为0.002~5.000 ng/L。将建立的方法应用于北京部分自备井水、市政末梢水和地表水样品的分析,结果在自备井水样中检出26种药物。     

Determination of abamectin in soil samples using high-performance liquid chromatography with tandem mass spectrometry

Abamectin, which is comprised of a mixture of avermectins B1a and B1b, is a natural pesticide used as an anti-parasitic agent in livestock, ornamental, and agricultural crops, which can potentially be transported to aquatic systems. These compounds are highly toxic to both aquatic vertebrates and invertebrates at low concentrations in water. This investigation developed high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) techniques to support automated extraction by an accelerated solvent extraction (ASE) system and chromatographic techniques to measure residues of avermectins in complex soil samples. HPLC along with atmospheric pressure chemical ionization (APCI) MS/MS was used for separation and determination of avermectin isomers in soil samples. Average method recovery for abamectin by UV was 91%, while detection by MS/MS resulted in a 68% recovery for abamectin. Individual method recoveries by MS/MS were 53.6% for avermectin B1a and 36.8% for avermectin B1b. The use of tandem technology eliminated matrix interferences and resulted in an approximately eight-fold increase in sensitivity.     

Ultra trace determination of 31 pesticides in water samples by direct injection-rapid resolution liquid chromatography-electrospray tandem mass spectrometry

A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for the detection of pesticides in tap and treated wastewater was developed and validated according to the ISO/IEC 17025:1999. Key features of this method include direct injection of 100 μL of sample, an 11 min separation by means of a rapid resolution liquid chromatography system with a 4.6 mm × 50 mm, 1.8 μm particle size reverse phase column and detection by electrospray ionization (ESI) MS-MS. The limits of detection were below 15 ng L⁻¹ and correlation coefficients for the calibration curves in the range of 30-2000 ng L⁻¹ were higher than 0.99. Precision was always below 20% and accuracy was confirmed by external evaluation. The main advantages of this method are direct injection of sample without preparative procedures and low limits of detection that fulfill the requirements established by the current European regulations governing pesticide detection.