Automated screening of reversed‐phase stationary phases for small‐molecule separations using liquid chromatography with mass spectrometry

There are various reversed‐phase stationary phases that offer significant differences in selectivity and retention. To investigate different reversed‐phase stationary phases (aqueous stable C₁₈, biphenyl, pentafluorophenyl propyl, and polar‐embedded alkyl) in an automated fashion, commercial software and associated hardware for mobile phase and column selection were used in conjunction with liquid chromatography and a triple quadrupole mass spectrometer detector. A model analyte mixture was prepared using a combination of standards from varying classes of analytes (including drugs, drugs of abuse, amino acids, nicotine, and nicotine‐like compounds). Chromatographic results revealed diverse variations in selectivity and peak shape. Differences in the elution order of analytes on the polar‐embedded alkyl phase for several analytes showed distinct selectivity differences compared to the aqueous C₁₈ phase. The electron‐rich pentafluorophenyl propyl phase showed unique selectivity toward protonated amines. The biphenyl phase provided further changes in selectivity relative to C₁₈ with a methanolic phase, but it behaved very similarly to a C₁₈ when an acetonitrile‐based mobile phase was evaluated. This study shows the value of rapid column screening as an alternative to excessive mobile phase variation to obtain suitable chromatographic settings for analyte separation.     

Characterization of the precolumn bio trap 500 C18 for direct injection of plasma samples in a column-switching system

Summary A new restricted access media (RAM) type of precolumn, Bio Trap 500 C₁₈, for direct injection of plasma samples in column-switching systems was evaluated with respect to the elution of plasma proteins in different mobile phases, the loading capacity of plasma samples, the chromatographic behavior during plasma injections and protein contamination of the packing and sealings. More than 95% of plasma proteins could be excluded from the precolumn within three minutes for all selected mobile phases. Quantitative analyte recoveries could be obtained by injecting plasma samples ranging from 5 to 500 μL with the analyte mass>150 ng onto a BioTrap 500 C₁₈ column (20×4 mm I.D.). One precolumn tolerated about 15 mL of plasma injection without out noticeable change in retention and pressure. Clogging of the precolumn was encountered (≥45 mL of plasma) due mainly to the adsorption of proteins on the packing. The performance of the analytical column (Kromasil C₁₈) was also examined. The column efficiency decreased by 60% after processing 45 mL plasma in total.     

Optimization of chromatography to overcome matrix effect for reliable estimation of four small molecular drugs from biological fluids using LC–MS/MS

The article describes a systematic study to overcome the matrix effect during chromatographic analysis of gemfibrozil, rivastigmine, telmisartan and tacrolimus from biological fluids using LC–ESI–MS/MS. All four methods were thoroughly developed by the appropriate choice of analytical column, elution mode and pH of mobile phase for improved chromatography and overall method performance. Matrix effect was assessed by post-column analyte infusion, slope of calibration line approach and post-extraction spiking. The best chromatographic conditions established were: Acquity BEH C₁₈ (50 × 2.1 mm, 1.7 μm) column with 5.0 mm ammonium acetate, pH 6.0–methanol as the mobile phase under gradient program for gemfibrozil; Luna CN (50 × 2.0 mm, 3 μm) column with a mobile phase consisting of acetonitrile–10 mm ammonium acetate, pH 7.0 (90:10, v/v) for rivastigmine; Inertsustain C₁₈ (100 × 2.0 mm, 5 μm) column using methanol–2.0 mm ammonium formate, pH 5.5 (80: 20, v/v) as the mobile phase for isocratic elution of telmisartan; and Acquity BEH C₁₈ (50 × 2.1 mm, 1.7 μm) with methanol–10 mm ammonium acetate, pH 6.0 (95:5, v/v) as mobile phase for tacrolimus. The methods were thoroughly validated as per European Medicines Agency and US Food and Drug Administration guidance and were successfully applied for pharmacokinetic studies in healthy subjects.     

In situ continuous derivatization/pre-concentration of carbonyl compounds with 2,4-dinitrophenylhydrazine in aqueous samples by solid-phase extraction: Application to liquid chromatography determination of aldehydes

A rapid and straightforward continuous solid-phase extraction system has been developed for in situ derivatization and pre-concentration of carbonyl compounds in aqueous samples. Initially 2,4-dinitrophenylhydrazine, the derivatizing agent, was adsorbed on a C₁₈ mini-column and then 15-ml of sample were continuously aspirated into the flow system, where the derivatization and pre-concentration of the analytes (low-molecular mass aldehydes) were performed simultaneously. Following elution, 20 μl of the extract were injected into a LC-DAD system, in which hydrazones were successfully separated in 12 min on a RP-C₁₈ column using a linear gradient mobile phase of acetonitrile-water of 60-100% acetonitrile for 8 min, flowing at 0.5 ml/min. The whole analytical process can be accomplished within ca. 35 min. Under optimum conditions, limits of detection were obtained between 0.3 and 1.0 μg/l and RSDs (inter-day precision) from 1.2 to 4.6%. Finally, some applications on water samples are presented with recoveries ranged from 95.8 to 99.4%.     

Simultaneous determination of five bioactive constituents in the traditional Chinese medicinal preparation refined xue-fu-zhu-yu-tang by high-performance liquid chromatography with diode-array UV detection

A high-performance liquid chromatographic method for the simultaneous determination of oxypaeoniflorin, paeoniflorin, ferric acid, naringin, and neohesperidin in a traditional Chinese medicinal preparation, refined xue-fu-zhu-yu-tang, was developed. Separations were carried out with a ZORBAX SB-C₁₈ column along with an Agilent C₁₈ precolumn by linear gradient elution using 1% acetic acid-methanol (v/v: 0 min, 80/20; 15 min, 70/30; 35 min, 60/40; 55 min, 60/40) as the mobile phase at a flow rate of 0.5 mL/min. The analytes were detected with a diode-array detector at their maximum UV wavelengths. The correlation coefficients of the calibration curve for the analytes exceeded 0.9999. The recoveries were in the range 95.95–104.42 % with RSD less than 1.85%, and the precision of this method was better than 1.80%. The effects of several factors on the chromatographic behavior and sample extraction of the analytes were compared. In addition, the contents of these bioactive constituents in six different samples of this preparation were analyzed by using the optimized high-performance liquid chromatographic method. The text was submitted by the authors in English.     

Quantitative evaluation main of the components in Paeoniae Radix Alba–Atractylodis Macrocephalae Rhizoma herbal pair by high‐performance liquid chromatography

The aim of this study was to investigate the influence of compatibility on the contents of main compounds in Paeoniae Radix Alba and Atractylodis Macrocephalae Rhizoma. Ten compounds were separated on an Inertsil ODS‐SP Extend C₁₈ column (250 mm × 4.6 mm, 5 μm) and detected by a diode array detector with the mobile phase consisting of aqueous phosphoric acid (0.1%, v/v; A) and acetonitrile (B) by linear gradient elution. All analytes showed good linearity over a wide concentration range (r² ≥ 0.9989). The limits of detection and quantification were <8.10 and 10.80 μg/mL, respectively. The intra‐ and interday variations were <4.36%. The average recoveries were observed from 94.90 to 103.38%, with relative standard deviation ranging from 1.23 to 3.15% for the analytes. The established method was reliable enough for global quality evaluation of Paeoniae Radix Alba, Atractylodis Macrocephalae Rhizoma, and their co‐decoctions.     

Simultaneous determination of 11 antibiotics and their main metabolites from four different groups by reversed-phase high-performance liquid chromatography-diode array-fluorescence (HPLC-DAD-FLD) in human urine samples

A new, accurate and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) as analytical method for the quantitative determination of 11 antibiotics (drugs) and the main metabolites of five of them present in human urine has been worked out, optimized and validated. The analytes belong to four different groups of antibiotics (sulfonamides, tetracyclines, penicillins and anphenicols). The analyzed compounds were sulfadiazine (SDI) and its N⁴-acetylsulfadiazine (NDI) metabolite, sulfamethazine (SMZ) and its N⁴-acetylsulfamethazine (NMZ), sulfamerazine (SMR) and its N⁴-acetylsulfamerazine (NMR), sulfamethoxazole (SMX), trimetroprim (TMP), amoxicillin (AMX) and its main metabolite amoxicilloic acid (AMA), ampicillin (AMP) and its main metabolite ampicilloic acid (APA), chloramphenicol (CLF), thiamphenicol (TIF), oxytetracycline (OXT) and chlortetracycline (CLT). For HPLC analysis, diode array (DAD) and fluorescence (FLD) detectors were used. The separation of the analyzed compounds was conducted by means of a Phenomenex^® Gemini C₁₈ (150 mm × 4.6 mm I.D., particle size 5 μm) analytical column with LiChroCART^® LiChrospher^® C₁₈ (4 mm × 4 mm, particle size 5 μm) guard column. Analyzed drugs were determined within 34 min using formic acid 0.1% in water and acetonitrile in gradient elution mode as mobile phase. A linear response was observed for all compounds in the range of concentration studied. Two procedures were optimized for sample preparation: a direct treatment with methanol and acetonitrile and a solid phase extraction procedure using Bond Elut^® Plexa™ columns. The method was applied to the determination of the analytes in human urine from volunteers under treatment with different pharmaceutical formulations. This method can be successfully applied to routine determination of all these drugs in human urine samples.     

Determination of 19 sulfonamides residues in pork samples by combining QuEChERS with dispersive liquid–liquid microextraction followed by UHPLC–MS/MS

A new simple and rapid pretreatment method for simultaneous determination of 19 sulfonamides in pork samples was developed through combining the QuEChERS method with dispersive liquid–liquid microextraction followed by ultra‐high performance liquid chromatography with tandem mass spectrometry. The sample preparation involves extraction/partitioning with QuEChERS method followed by dispersive liquid–liquid microextraction using tetrachloroethane as extractive solvent and the acetonitrile extract as dispersive solvent that obtained by QuEChERS. The enriched tetrachloroethane organic phase by dispersive liquid–liquid microextraction was evaporated, reconstituted with 100 μL acetonitrile/water (1:9 v/v) and injected into an ultra‐high performance liquid chromatography with a mobile phase composed of acetonitrile and 0.1% v/v formic acid under gradient elution and separated using a BHE C₁₈ column. Various parameters affecting the extraction efficiency were investigated. Matrix‐matched calibration curves were established. Good linear relationships were obtained for all analytes in a range of 2.0–100 μg/kg and the limits of detection were 0.04–0.49 μg/kg. Average recoveries at three spiking levels were in the range of 78.3–106.1% with relative standard deviations less than 12.7% (n = 6). The developed method was successfully applied to determine sulfonamide residues in pork samples.     

Determination of the N-methyl-D-aspartate receptor NR2B subunit blocker Ro 63-1908 in rat, cynomolgus monkey and human plasma by high-performance liquid chromatography with column switching and fluorescence detection

A HPLC method with automated column switching was developed and validated for the determination of Ro 63-1908 in rat and cynomolgus monkey plasma. Human plasma was used for calibration and was also included in the validation process. Ro 63-1908 belongs to a class of neuroprotective N-methyl-D-aspartate (NMDA) receptor blockers which were in development for the treatment of stroke and traumatic brain injury. The method involves deproteinisation of plasma samples with ethanol and direct injection of the supernatant (1.4 ml) into the HPLC column-switching system. To prevent a breakthrough of the analyte and the internal standard on the precolumn (Purospher RP-18, 75x4 mm) due to the high ethanol content, the injection solution was diluted, on-line, using an additional pump and a T-piece. 1% ammonium acetate-ethanol (100:2, v/v) was used as mobile phase for injection, as well as for on-line dilution, resulting in pre-concentration of the analyte and the internal standard on the precolumn. As Purospher RP-18 is a non-endcapped stationary phase with a special selectivity for amines, the analyte and the internal standard could then be selectively eluted with 30% acetonitrile (without any buffer in the mobile phase) and transferred to the analytical column [consisting of two coupled columns (125+250x4 mm) packed with Superspher 60 RP-select B], where they were separated by gradient elution and detected by fluorescence detection. Compared to the use of a 125 mm long precolumn and dilution of the supernatant with ammonium acetate prior to injection, the 75 mm precolumn and the on-line dilution procedure allowed about one third shorter run times (21 min) and, therefore, a higher sample throughput. The limit of quantification was 1 ng/ml using 0.4 ml plasma. The method was applied to more than 670 plasma samples from pharmacokinetic and toxicokinetic studies and is also suitable for other matrices and NMDA receptor blockers.     

Ultra high-performance liquid chromatography of porphyrins

An ultra high‐performance liquid chromatographic (UHPLC) system was developed and optimized for the separation of porphyrins of clinical interest. Optimum conditions for the simultaneous separation of uroporphyrin, hepta‐, hexa‐, penta‐carboxylic acid porphyrins and coproporphyrin and their type I and III isomers on a Thermo Hypersil BDS C₁₈ column (2.4 µm particle size, 100 × 2.1 mm i.d.) using a gradient elution with 10% (v/v) acetonitrile in 1.0 m ammonium acetate buffer (pH 5.16) and 10% (v/v) acetonitrile in methanol at a flow‐rate of 0.4 mL/min. The effect of mobile phase buffer molarity on the sensitivity of fluorescence detection and resolution of porphyrin isomers was investigated. The method was successfully applied to the analysis of porphyrins extracted from the urine and faeces of patients with various human porphyrias. Copyright © 2011 John Wiley & Sons, Ltd.     

超高效液相色谱-三重四极杆/复合线性离子阱质谱法同时快速测定血浆和尿液中84种有毒植物成分

采用超高效液相色谱-三重四极杆/复合线性离子阱的质谱联用技术,建立了同时快速测定血浆和尿液中84种有毒植物成分的方法。血浆样品经乙腈沉淀去蛋白和除磷脂、尿液样品经甲醇稀释后直接进样,以含0.1%（体积分数,下同）甲酸和2 mmol/L甲酸铵的97%乙腈水溶液、含0.1%甲酸的2 mmol/L甲酸铵水溶液作为流动相进行梯度洗脱,在Acquity BEH C₁₈色谱柱上实现分离,在电喷雾正离子多离子监测触发的增强子离子扫描（MRM-IDA-EPI）模式下检测,基质工作曲线内标法定量。血浆和尿液中84种待测物在相应的浓度范围内线性关系良好,相关系数均大于或等于0.9911,血浆和尿液中的检出限（S/N=3）分别为0.01~1和0.03~2 μg/L,准确度（平均加标回收率）为70.6%~124.5%,日内和日间精密度分别为0.7%~18.4%和1.1%~18.5%。该法简单、快速、灵敏、准确,可用于血浆和尿液中84种有毒植物成分的中毒检测。     

Comparative pharmacokinetic study of four major bioactive components after oral administration of Zhi‐Zi‐Hou‐Po decoction in normal and corticosterone‐induced depressive rats

A highly selective and efficient LC–MS/MS method was developed to determine the plasma concentration of magnolol, hesperidin, neohesperidin and geniposide following oral administration of Zhi‐Zi‐Hou‐Po decoction in normal and depressed rats. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was performed on an XTerra^® MS C₁₈ column using a gradient elution with a mobile phase composed of acetonitrile–0.1% aqueous formic acid. The proposed method was validated to be specific, accurate and precise for the analytes determination in plasma samples. The calibration curves displayed good linearity over definite concentration ranges for the analytes. The intra‐ and inter‐day precision of the proposed method at three different levels were all within <11.13% and the relative errors ranged from ?8.46 to 8.93%. The recovery of the four compounds ranged from 82.72 to 89.08% and no apparent matrix effect was observed during sample analysis. After full validation, the established method was successfully applied for comparing the pharmacokinetics of four components between normal and depressed rats. The results showed that the AUC and C_max of four analytes in depressed rats were significantly different from those in normal rats and might provide helpful information to guide the clinical use of Zhi‐Zi‐Hou‐Po to treat depression.     

Turbo flow在线净化-超高效液相色谱-串联质谱法检测水果中5种咪唑类农药残留

建立了Turbo flow （TF）在线净化-超高效液相色谱-串联质谱同时检测水果中吡咪唑、咪唑烟酸、咪鲜胺、咪唑嗪和咪唑菌酮等5种咪唑类农药的方法。以饱和氯化钠溶液溶解样品,乙腈提取,蒸干,乙腈-水（1：1,v/v）溶液定容后进入Turbo flow-超高效液相色谱-串联质谱系统分析,外标法定量。对影响TF净化的条件如TF色谱柱、流动相、洗脱溶液、洗脱速率等进行了优化。在优化的实验条件下,以Turbo flow C18 （50 mm×1.0 mm）为净化柱,Hypersil GOLD aQ （100 mm×2.1 mm）为分析柱,乙腈和5 mmol/L甲酸铵溶液（含0.1%（v/v）甲酸）为流动相进行梯度洗脱,在电喷雾正离子选择反应监测模式下进行检测。结果表明,各目标化合物在0.0075~0.75 mg/L范围内线性关系良好（相关系数均大于0.99）,定量限为0.005 mg/kg。对实际样品分别加标0.005、0.01、0.05和0.5 mg/kg,回收率为71.2%~122.4%,相对标准偏差（RSD）为0.5%~8.9%。该方法简便、快速,结果准确可靠,适用于水果中5种咪唑类农药残留的检测。     

Retention Mechanism Studies of Selected Amino Acids and Vitamin B6 on HILIC Columns with Evaporative Light Scattering Detection

The goal of the study was to investigate separation mechanism of selected “essential” amino acids (leucine, isoleucine, threonine, tryptophan, proline, and glycine) and vitamin B6 in hydrophilic interaction liquid chromatography (HILIC) with the evaporative light scattering detection. Chromatographic measurements were made on three different HILIC columns: amide-silica (TSK-gel Amide-80), amino-silica (TSK-gel NH₂-100), and cross-linked diol (Luna HILIC). The retention behaviour of the analytes was investigated as a function of different binary hydro-organic mobile phases containing 10–90 % (v/v) acetonitrile. The compounds studied were separated under isocratic and gradient conditions. The best results of tested biologically active compounds separation were obtained on the TSK-gel NH₂-100 column. TSK-gel NH₂ column showed mixed HILIC–ion-exchange mechanism, the highest separation efficiency and better selectivity and resolution for tested analytes than the other studied column, especially at concentration of water in mobile phase lower than 30 % (v/v). Special attention was dedicated to the study of interactions among the stationary phase, mobile phase and the analytes.     

A Novel RP-LC Method for Determination of pK a Values of Some Anticancer Agents and Their Assay

A simple, reliable, and rapid RP-LC method has been developed for the determination of some anticancer drugs (daunorubicin, doxorubicin and vincristine sulfate) in their dosage forms and human urine. These compounds are well separated on a C18 column using the mobile phase consisting of a mixture of acetonitrile (50:50; v/v) at a flow rate of 1.5 mL min^?1. The analyte peaks were detected at 235 nm for doxorubicin and daunorubicin, and 220 nm for vincristine. Linearity was obtained in different concentration ranges between 0.10 and 12 μg mL^?1 for all compounds. Good sensitivity for all analytes was observed with DAD detection. LOD and LOQ of the method were found satisfying. The proposed method has been extensively validated in accordance with ICH guidelines and obtained results proved that the proposed method was precise, accurate, selective, and sensitive for simultaneous analysis of studied compounds. All analytical procedures including sample preparation, flow rate, and run time were at low levels. Also, pK _a values were determined using the dependence of the retention factor on the pH of the mobile phase. The effect of the mobile phase composition on the ionization constant was studied by measuring the pK _a at different methanol–water mixtures, ranging between 45 and 60 % (v/v).     

Simultaneous detection of three antiviral and four antibiotic compounds in source‐separated urine with liquid chromatography

An analytical method for the simultaneous screening of three antiviral agents (nevirapine, zidovudine, lamivudine), four antibiotics (sulfamethoxazole, trimethoprim, ciprofloxacin, rifampicin) and one reference compound (carbamazepine) in human urine was developed. Separation was achieved with a Kinetex XB‐C₁₈ (75 × 4.6 mm, 2.6 μm) column after the extraction of pharmaceuticals from urine with SPE. Gradient elution with a mobile phase consisting of acetonitrile and 10 mM KH₂PO₄ (pH 2.5), and diode array detection with monitoring at 210 and 264 nm was applied. The developed method was validated in terms of selectivity, linearity, stability and sensitivity. Repeatability (n = 3) and between‐day precision (n = 3) revealed RSD <5%. The detection limits were estimated as 0.02–0.54 g/L (depending on compound). The method was validated for human urine and successfully applied to the simultaneous quantification of selected compounds. Strata‐X cartridges provided good recoveries ranging from 81 to 109%. The limits of detection for urine varied between 0.04 and 1.61 g/L. The method is suitable for the fast determination of selected pharmaceuticals from source‐separated urine samples for further environmental risk assessment and degradation potential evaluation. It provides a way to enhance safe nutrient recycling from wastewater streams and promotes the safe use of urine as fertiliser.     

Determination of the N-methyl- -aspartate receptor NR2B subunit blocker Ro 63-1908 in rat, cynomolgus monkey and human plasma by high-performance liquid chromatography with column switching and fluorescence detection

A HPLC method with automated column switching was developed and validated for the determination of Ro 63-1908 in rat and cynomolgus monkey plasma. Human plasma was used for calibration and was also included in the validation process. Ro 63-1908 belongs to a class of neuroprotective N-methyl- -aspartate (NMDA) receptor blockers which were in development for the treatment of stroke and traumatic brain injury. The method involves deproteinisation of plasma samples with ethanol and direct injection of the supernatant (1.4 ml) into the HPLC column-switching system. To prevent a breakthrough of the analyte and the internal standard on the precolumn (Purospher RP-18, 75×4 mm) due to the high ethanol content, the injection solution was diluted, on-line, using an additional pump and a T-piece. 1% ammonium acetate–ethanol (100:2, v/v) was used as mobile phase for injection, as well as for on-line dilution, resulting in pre-concentration of the analyte and the internal standard on the precolumn. As Purospher RP-18 is a non-endcapped stationary phase with a special selectivity for amines, the analyte and the internal standard could then be selectively eluted with 30% acetonitrile (without any buffer in the mobile phase) and transferred to the analytical column [consisting of two coupled columns (125+250×4 mm) packed with Superspher 60 RP-select B], where they were separated by gradient elution and detected by fluorescence detection. Compared to the use of a 125 mm long precolumn and dilution of the supernatant with ammonium acetate prior to injection, the 75 mm precolumn and the on-line dilution procedure allowed about one third shorter run times (21 min) and, therefore, a higher sample throughput. The limit of quantification was 1 ng/ml using 0.4 ml plasma. The method was applied to more than 670 plasma samples from pharmacokinetic and toxicokinetic studies and is also suitable for other matrices and NMDA receptor blockers.     

在线固相萃取结合液相色谱-线性离子阱多级质谱法同时检测生物样品中7种乌头类生物碱

建立了在线固相萃取(on-line SPE)结合液相色谱-线性离子阱多级质谱(LC-LIT/MSⁿ)同时测定全血、尿液和肝组织样品中7种乌头类生物碱的分析方法,并根据7种乌头类生物碱的多级质谱碎片对裂解规律进行了推测和总结。用乙腈沉淀样品中的蛋白质,于稀释和离心后直接进样。经Waters Oasis^® HLB在线SPE柱富集纯化,以0.1%(v/v)甲酸/乙酸铵溶液-0.1%(v/v)甲酸/甲醇溶液为流动相,以Accucore C18为分析柱进行梯度洗脱;在电喷雾电离(ESI)正离子模式下测定;扫描方式为连续反应监测(CRM)。在考察的质量浓度范围内,7种乌头类生物碱的标准曲线符合二阶方程(权重因子1/x),相关系数为0.9991~0.9999;在全血和尿液中的方法检出限为0.02~0.60 ng/mL,在肝组织中的方法检出限为0.02~0.40 ng/g;加标回收率为91.1%~104.7%,日内精密度和日间精密度分别为0.2%~10.7%、1.0%~13.7%(n=6)。该方法简单准确,灵敏度高,能够满足生物样品中7种乌头类生物碱的快速分析。     

Isolation of new quinidine metabolites and simultaneous determination of quinidine and its metabolites in blood and urine by direct injection HPLC analysis

Summary New quinidine metabolites, including 10,11-dihydrodiol quinidine N-oxide, 10,11-dihydrodiol quinidine and their glucuronides, were found in human urine. A quinidine monitoring HPLC method including these metabolites, is proposed by the direct injection of body fluid samples onto the precolumn for deproteinization followed by reverse phase separation in the analytical column with a column switching technique. The recovery of spiked quinidine and its metabolites in plasma was quantitative (98–102%) with good reproducibility (C.V.: 1.6–4.0%). Several clinical samples such as whole blood and urine were analyzed by the present method.     

高效液相色谱-串联质谱法测定饲料和卧床土中的环境雌激素

建立了饲料和卧床土中雌三醇、雌二醇、雌酮、双酚A和己烯雌酚5种环境雌激素的固相萃取结合高效液相色谱-串联质谱(HPLC-MS/MS)测定方法。对色谱流动相、质谱条件、固相萃取柱等影响因素进行了优化,得到的最优化条件为:样品经乙腈提取后,用固相萃取柱(NH₂-SPE)进行富集,采用Acquity UPLC^TM HSS T₃色谱柱分离,以乙腈-甲醇(4:1, v/v)与0.01%氨水为流动相,采用梯度洗脱,在负离子模式下进行MS/MS测定。在该优化条件下,5种环境雌激素的检出限(以信噪比为3计)为0.06~0.22 μg/kg,回收率为81.70%~102.20%,相对标准偏差小于10.00%。该方法用于饲料和卧床土中的5种环境雌激素残留量的测定具有简便、快速、灵敏的特点。