高效液相色谱-电喷雾串联质谱法测定鱼体中雪卡毒素

建立了高效液相色谱-电喷雾串联质谱法测定鱼体中雪卡毒素P-CTX1含量的方法.鱼类样品经丙酮提取后,用冷冻脱脂,经PSA固相萃取柱净化后, C18色谱柱分离,采用电喷雾串联四极杆质谱进行检测.结果表明,雪卡毒素在0.5～20 μg/L范围时,线性关系良好(r=0.9998).P-CTX1在添加浓度为1.0～20.0 ng/kg范围内的平均回收率为82.3%～87.2%, 相对标准偏差小于7.8%,方法的定量检出限为0.1 μg/L.     

Determination of Ochratoxin A in wine at sub ng/mL levels by solid-phase microextraction coupled to liquid chromatography with fluorescence detection

Solid-phase microextraction (SPME), using a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber, interfaced with liquid chromatography-fluorescence detection (LC-FD) has been applied to the determination of Ochratoxin A (OTA) in wine samples. Compared to the most widely adopted extraction/clean-up procedure based on immunoaffinity columns (IAC), the solventless extraction is simpler and cost-effective, requiring the simple immersion of the fiber in diluted wine samples. Furthermore, a fast LC separation is achieved under isocratic conditions. The linear range investigated in wine was 0.25-8 ng/mL; at fortification levels of 0.5 and 2 ng/mL, within-day intra-laboratory precision (repeatability) values, expressed as RSD%, were 5.9 and 5.1, respectively, whereas between days (n = 4) precision was 8.5 and 7.1%, respectively. The limit of detection (LOD) at a signal-to-noise (S/N) ratio of 3 was 0.07 ng/mL; the limit of quantification (LOQ) calculated at S/N = 10 was 0.22 ng/mL, well below the European regulatory level of 2 ng/mL. The potential of the method has been demonstrated by the analysis of a number of different wine samples.     

分散液液微萃取-上浮溶剂固化/高效液相色谱法测定沉积物中的十溴联苯醚

建立了沉积物中痕量十溴联苯醚的分散液液微萃取-上浮溶剂固化-高效液相色谱-紫外法(DLLME-SFO-HPLC-UV)。以正交试验数据为训练样本,采用BP(Back propagation)神经网络模型优化了分散液液微萃取-上浮溶剂固化条件:分散剂为1.00mL甲醇、萃取剂为35.0μL十二醇、NaCl质量浓度为10.00%、萃取时间10min和pH=5,其萃取率(ER)可达62.22%。方法的线性范围为3.5～1400ng/g(r=0.9960),检出限(LOD)和定量限(LOQ)分别为2.3pg/g(S/N=2)和5.6pg/g(S/N=5),实际样品的加标回收率为97.7%～104.2%。本方法集萃取、富集、分离步骤于一体,简化了沉积物中十溴联苯醚的前处理过程。     

鲁米诺-H2O2体系化学发光对邻氯代苯亚甲基丙二腈和丙二腈的研究

基于鲁米诺-过氧化氢体系对邻氯代苯亚甲基丙二腈(CS)和丙二腈的化学发光的检测,考察了其反应动力学曲线,详细研究了pH值,鲁米诺浓度,过氧化氢浓度,本底信号的稳定性对化学发光强度的影响.CS的检测线性范围为10-2～10-5mol/L,绝对检测限为1.1ng(S/N=3/1).丙二腈的检测线性范围为10-3～10-6mol/L,绝对检测限为0.5ng(S/N=3/1).建立了鲁米诺-过氧化氢体系对液相化学发光对CS和丙二腈的分析方法,对CS的沙土样品进行测定,结果令人满意.     

固相萃取-气相色谱-负化学源质谱法测定人血清中的多溴联苯醚

采用OasisHLB固相萃取柱萃取血清中的多溴联苯醚(PBDEs),经浓硫酸柱上除脂后,利用气相色谱-负化学源质谱法测定BDE-17、28、47、66、99、100、153、154、183和209共10种PBDEs组分。BDE-209的测定采用DB-5 ms色谱柱(15 m×0.25 mm×0.1 μm),其他组分采用VF-5 ms色谱柱(30 m×0.25 mm×0.25 μm)。对样品中蛋白质的去除溶剂和固相萃取条件(如洗脱溶剂及其用量)进行了优化。胎牛血清中的加标回收试验结果显示,各PBDEs单体相对于内标的平均回收率为78.5%～109.7%,日内测定的相对标准偏差(RSD)为0.3%～7.4%,日间测定的RSD为1.4%～14.1%。胎牛血清中三溴～七溴联苯醚的检出限(信噪比为3)为0.10～0.27 ng/L;定量限(信噪比为10)除了BDE-209为7.91 ng/L外,其他PBDEs为0.35～0.91 ng/L。采用本方法测定标准参考物质SRM1957和SRM1958,结果在参考值范围内。实验结果表明,本方法灵敏度高、准确度和精密度好,简便快速,溶剂消耗量少,适用于人体血清中三至十位溴取代联苯醚的测定。     

液相色谱-串联质谱分析组织中基因组脱氧核糖核酸羟甲基胞嘧啶水平

5-羟甲基胞嘧啶通过阻止脱氧核糖核酸(DNA)甲基化转移酶1(DMNT1)甲基化胞嘧啶来影响DNA甲基化的程度。本文建立了液相色谱-串联质谱(LC-MS/MS)测定组织中全基因组5-羟甲基胞嘧啶水平的方法。采用苯酚-氯仿提取组织DNA,提取的DNA用88%甲酸在140 ℃下裂解,DNA裂解液加入同位素胞嘧啶作内标,经N2吹干后,加乙腈-水(9:1, v/v)溶解,用LC-MS/MS检测5-羟甲基胞嘧啶的含量,并计算全基因组中5-羟甲基胞嘧啶的水平。结果表明,5-羟甲基胞嘧啶的线性范围为0.1～30 ng/mL,相关系数为0.9969,检出限(信噪比为3计)和定量限(信噪比为10计)分别为0.057 ng/mL和0.090 ng/mL;日内相对标准偏差和日间相对标准偏差分别为5.13%和6.24%;加标回收率为90.24%～97.53%。用该方法检测了大鼠大脑组织DNA羟甲基化水平,平均结果为0.66%。该方法简便,重现性好,灵敏度较高,能满足全基因组5-羟甲基胞嘧啶定量检测的要求。     

Determination of levodopa and biogenic amines in urine samples using high-performance liquid chromatography

A chromatographic system is developed for the separation and determination of levodopa, biogenic amines, and their metabolites from the catecholamines group: dopamine (DA), epinephrine (E), normetanephrine (NMN), metanephrine (MN), 3,4-dihydroxyphenylacetic acid (DOMA), 3-metoxy-4-hydroxyphenyl-glycol (MHPG), and homovanillic acid (HVA); and indoloamines group: serotonin (5HT) and 5-hydroxyindole-3-acetic acid (5HIAA) in urine. The limit of detection (LOD) and limit of quantitation (LOQ) are determined for all compounds with signal-to-noise ratio (S/N) of 3 and 10, respectively. LOD 10 (ng/mL) and LOQ 30 (ng/mL) are determined for L-DOPA, DOMA, E, NMN, DA, MN, and MHPG, as well as LOD 8 (ng/mL) and LOQ 24 (ng/mL) for HVA, 5HT, and 5HIAA. A fluorescence detector is used. Gradient elution with acetate buffer (pH=4.66) with methanol is applied. In urine samples from patients treated with levodopa, the following concentrations (microg/mL) of analytes are determined: L-DOPA 3.73-46.80, DOMA 1.43-28.43, E 0.83-13.57, NMN 2.58-8.81, DA 24.07-62.11, MN 0.89-66.20, MHPG 6.72-63.64, 5HT 22.96-95.27, 5HIAA 1.45-14.77, and HVA 0.21-15.07.     

Determination of perfluorooctane sulfonate in river water by liquid chromatography/atmospheric pressure photoionization mass spectrometry by automated on-line extraction using turbulent flow chromatography

A simple, fast and sensitive liquid chromatography/atmospheric pressure photoionization mass spectrometry (LC/APPI-MS) method, with automated on-line extraction using turbulent flow chromatography (TFC), was developed for the determination of perfluorooctane sulfonate (PFOS) in river water. In this method, following an on-line extraction by injection onto a column under TFC conditions, PFOS is back-flushed onto a reversed-phase column via on-line column switching, and resolved chromatographically at a laminar flow rate of 1 mL min(-1). Using this tandem LC-LC/APPI-MS system the extraction, separation and selective detection of PFOS in river water could be achieved with satisfactory selectivity and sensitivity. The limit of detection (LOD) (S/N = 3) and the limit of quantitation (LOQ) (S/N = 10)were 5.35 and 17.86 pg mL(-1). The described procedure was very simple since no off-line sample preparation was required, total analysis time being 18.75 min.     

高效液相色谱-串联质谱法测定蜂胶中的氯霉素

建立了高效液相色谱-串联质谱(HPLC-MS/MS)测定蜂胶中氯霉素残留的方法。样品用水提取后,以醋酸铅溶液作为沉淀剂除去样品中的大部分黄酮类成分,用液-液萃取的方式提取样品中的氯霉素残留,最后以HPLC-MS/MS对样品进行定性、定量分析。该方法采用内标法定量,线性范围为0.05～2.0 μg/L,相关系数为0.9996;方法的检出限(以信噪比(S/N)为3计)和定量限(以S/N=10计)分别为0.1 μg/kg和0.3 μg/kg;回收率范围为70.1%～94.0%,日内精密度小于10%,日间精密度在15.0%以下。该方法简便快捷,能除去蜂胶中的大部分黄酮类成分,减少了干扰,可以用于蜂胶中氯霉素残留的测定。     

液相色谱-串联质谱法测定育肥猪配合饲料中的阿奇霉素

通过对提取溶剂、净化方法及色谱-质谱条件的优化,建立了配合饲料中阿奇霉素(AZM)的液相色谱-串联质谱测定方法。样品经乙腈超声波提取,MCX固相萃取柱净化,BDS Hypersil C_(18)(2.4μm,100 mm×2.1 mm)色谱柱分离,以甲醇-0.05 mol/L乙酸铵水溶液为流动相梯度洗脱,正离子模式电离,多反应监测模式检测,同位素内标法定量。在优化条件下,AZM在1~250μg/L范围内线性关系良好,相关系数(r~2)为0.999 1,检出限(S/N≥3)为2.8μg/kg,定量下限(S/N≥10)为8.4μg/kg;在0.5,1,5,10 mg/kg加标水平下,回收率为87.0%~106.6%,批内相对标准偏差为0.58%~5.4%,批间相对标准偏差为3.1%~5.4%。该方法准确、灵敏,选择性强,基质干扰小,可用于配合饲料中AZM的测定。     

液相色谱-电喷雾串联质谱法测定生姜中的215种农药残留

建立了生姜中215种农药多残留测定的液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)方法。样品用1%醋酸-乙腈溶液均质提取,经Sep-Pak Vac固相萃取柱净化,乙腈-甲苯(3:1, v/v)洗脱,旋转蒸发浓缩至约0.5 mL后,于室温氮气吹干,用乙腈-水(3:2, v/v)溶解,以电喷雾电离串联质谱在正离子多反应监测(MRM)模式下进行测定。在定量限水平进行添加回收率实验,方法的回收率范围为68.1%～132.6%,其中回收率在70%～120%的占94.4%,相对标准偏差(RSD)范围为0.4%～25.0%。方法的检出限(S/N=3)和定量限(S/N=10)范围分别为0.01～70.45 μg/L和0.04～234.84 μg/L。该方法操作简便,灵敏度、准确度和精密度均符合农药多残留检测技术要求,适用于生姜中215种农药多残留的快速测定。     

胶束电动色谱-激光诱导荧光检测法测定肌松弛药巴氯芬

以4-氯-7-硝基苯并-2-氧杂-1,3-二唑(NBD-Cl)为柱前衍生试剂,建立了胶束电动色谱-激光诱导荧光检测法测定肌松弛药巴氯芬(BAL)的新方法。经过实验条件的优化,采用15 mmol/L硼砂、20 mmol/L十二烷基硫酸钠、10%(v/v)乙腈、pH 9.75的缓冲体系,在分离电压为17.5 kV、柱温为25 ℃的条件下,压力进样3.45 kPa(0.5 psi)×3 s,巴氯芬及其内标物的衍生产物在7 min内实现较好的基线分离,线性范围为0.025～25 mg/L,相关系数为0.9999,检出限(S/N=3)和定量限(S/N=10)分别为0.90 μg/L和6.25 μg/L。该方法被应用于巴氯芬制剂及加入巴氯芬对照品的尿液样品分析,回收率范围分别为101.6%～107.9%和107.0%～109.6%。该方法有望应用于巴氯芬药物制剂的质量监控以及为巴氯芬药物代谢的研究提供辅助手段。     

Determination of phenolic compounds in environmental water samples after solid-phase extraction with β-cyclodextrin-bonded silica particles coupled with a novel liquid-phase microextraction followed by gas chromatography-mass spectrometry

A novel approach for the sample pre-treatment and determination of eight phenolic compounds in environmental water samples has been developed by hyphenating solid-phase extraction (SPE) and liquid-phase microextraction (LPME) techniques based on solid organic drop combined with gas chromatography-mass spectrometry detection (GC-MS). After pre-concentration and purification of the sample through column containing 60 mg of β-cyclodextrin-bonded silica particles as stationary phase, under the optimum conditions, LPME technique has been performed on the eluent solution. Under the selected conditions, limit of detection (LOD) of 0.002-0.04 μg/L (S/N=3), limit of quantification (LOQ) of 0.007-0.15 μg/L (S/N=10), pre-concentration factor of 752-3135 and linearity range of 0.01-25 μg/L have been obtained. A reasonable repeatability (RSD≤9.5%, n=5) with satisfactory coefficient of determination has been obtained between 0.9981 and 0.9997. The relative recoveries of the waste, sea, river and well water samples were higher than 79%.     

Characterization and quantification of soy isoflavone metabolites in serum of renal transplanted patients by high-performance liquid chromatography/electrospray ionization mass spectrometry

During a dietary intervention study on 16 renal transplanted patients, in which 25 g/day of animal proteins were replaced with 25 g of soy proteins, the metabolic profile of soy isoflavones in serum was characterized. This paper describes a reliable and fast liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) method, in negative ion mode, allowing the characterization and simultaneous quantification of several soy isoflavone metabolites. Six metabolites were identified and quantified: daidzein ([M-H](-) at m/z 252.8), dihydrodaidzein (DHD, [M-H](-) at m/z 254.8), equol ([M-H](-) at m/z 240.9), O-desmethylangolensin (O-DMA, [M-H](-) at m/z 256.8), genistein ([M-H](-) at m/z 268.8), and dihydrogenistein (DHG, ([M-H(+)](-) at m/z 270.8). Quantification was assessed using two deuterated internal standards, D(3)-daidzein and D(4)-genistein. This method permitted a limit of quantification (LOQ, S/N = 10) and a limit of detection (LOD, S/N = 3) of 0.05 microM and 0.005 microM for all analytes, except for genistein, where the LOQ and LOD were 0.005 microM and 0.001 microM, respectively. The linearity ranges were from 0.005 to 1.5 microM for genistein, from 0.05 to 1.5 microM for DHG, and from 0.05 to 0.7 microM for the other metabolites. The relative standard deviations (RSDs) were between 0.19% and 13.9% at the LOQ concentration for all metabolites, and between 0.6% and 4.8% at the maximum concentration. On the basis of the results obtained in the dietary intervention study, it was possible to split the patients into five groups characterized by different metabolic pathways.     

基于离子色谱/电导检测的全脂奶粉中硫氰酸盐污染物的测定及前处理方法研究

建立了氢氧根淋洗/离子色谱/电导检测分析全脂奶粉中硫氰酸盐（SCN-）污染物的分析方法,对蛋白沉淀剂、提取条件、提取液净化技术、色谱条件等作了深入研究和优化。通过对淋洗液梯度的优化,将出峰时间控制在17 min内,且不受邻近组分干扰。方法在0.02~100 mg/L范围内具有良好的线性关系,相关系数（r）为0.999 9,方法定量下限（S/N=10）为0.3 μg/g,回收率为99%~102%。方法重现性好,3 d内对2.0 mg/L的标准溶液随机测试7次,其峰面积的相对标准偏差（RSD）为1.6%。     

Determination of trace level of perchlorate in Antarctic snow and ice by ion chromatography coupled with tandem mass spectrometry using an automated sample on-line preconcentration method

A new ion chromatography coupled with tandem mass spectrometry（IC-ESI-MS/MS） method,with automated sampling and on-line preconcentration,has been developed for the determination of perchlorate in Antarctic snow and ice at low part-per-trillion（ng/L） levels.To the best of our knowledge, this is the first time that an analytical method is used for the determination of perchlorate in Antarctic snow and ice.The IC-ESI-MS/MS instrumentation consisted of an ICS2000 ion chromatography（IC） system coupled to an API3200 electrospray tandem mass spectrometer（ESI-MS/MS）.On-line preconcentration was realized through a six-port injector valve,a TAC-ULP1 concentrator column and an AS auto-sampler.Multiple reaction monitoring（MRM） mode was used to quantify the perchlorate anion.The transition of ³⁵Cl¹⁶O₄^-（m/z 98.9） into ³⁵Cl¹⁶O₃^-（m/z 82.9） was monitored for quantifying the main analyte,and the transition of ³⁷Cl¹⁶O₄^-（m/z 100.9） into ³⁷Cl¹⁶O₃^-（m/z 84.9） was monitored for examining a proper isotopic abundance ratio of ³⁵Cl to ³⁷Cl,which was used as a confirmation tool.The limit of detection（LOD） and limit of quantitation（LOQ） for the method was 0.2 ng/ L and 0.5 ng/L,respectively.And this new method exhibited acceptable accuracy and precision for samples at ng/L levels.All the tested snow and ice samples were found to contain measurable amount of perchlorate,ranging from 10 ng/L to 340 ng/L.     

Enantioselective determination of arotinolol in human plasma by HPLC using teicoplanin chiral stationary phase

A sensitive enantioselective high-performance liquid chromatography (HPLC) method was developed and validated to determine S-(+)- and R-(-)-arotinolol in human plasma. Baseline resolution was achieved by using teicoplanin macrocyclic antibiotic chiral stationary phase (CSP) known as Chirobiotic T with a polar organic mobile phase consisting of methanol:glacial acetic acid:triethylamine, 100:0.1:0.1, (v/v/v) at a fl ow rate of 0.8 mL/min and UV detection set at 317 nm. Human plasma was spiked with stock solution of arotinolol enantiomers and labetalol as the internal standard. The assay involved the use of liquid-liquid extraction procedure with ethyl ether under alkaline condition for human plasma sample prior to HPLC analysis. Recoveries for S-(+)- and R-(-)-arotinolol enantiomers were in the range 93-103% at 200-1400 ng/mL level. Intra-day and inter-day precision calculated as %RSD was in the ranges 1.3-3.4 and 1.9-4.5% for both enantiomers, respectively. Intra-day and inter-day accuracies calculated as percentage error were in the ranges 1.2-3.5 and 1.5-6.2% for both enantiomers, respectively. Linear calibration curves in the concentration range 100-1500 ng/mL for each enantiomer showed a correlation coefficient (r) of 0.9998. The limit of quantitation (LOQ) and limit of detection (LOD) for each enantiomer in human plasma were 100 and 50 ng/mL (S/N = 3), respectively.     

Fast quantitative determination of melamine and its derivatives by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

A simple, sensitive and fast method for the determination of melamine and its derivatives in milk powder using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was developed. Neither time-consuming sample preparation, nor special target plates, or other extra equipment are necessary. The common matrix sinapinic acid (SA) was used with a dried-droplet preparation. Detection limits (signal-to-noise (S/N) ratio = 3) for standard solutions of melamine, ammeline and cyanuric acid were 10, 25 and 10 μg/L, respectively. The limit of quantification (LOQ) for melamine was 25 μg/L and excellent linearity (R(2): 0.9990) was maintained over the range of 10-2000 μg/L. Ammeline and cyanuric acid were analyzed with an LOQ of 50 μg/L and also excellent linearity (R(2): 0.9997 and R(2): 0.9998). Good accuracy and precision were obtained for all concentrations within the range of the standard curve. The developed method was successfully used for the determination of melamine, ammeline and cyanuric acid in milk powder samples with a simple sample preparation. The LOQ of melamine was 0.5 μg/g. Ammeline and cyanuric acid were detectable at 0.5 and 5 μg/g. This method showed excellent accuracy, precision and linearity and significantly reduces the needed analysis time, as only approximately 10 s/sample measuring time is required. To the authors' knowledge, this is the first published method to quantify melamine and derivatives by MALDI-TOF-MS.     

Separation of 9 Sulfonamide Drugs in ≈4 Min by Ultra-High Performance Supercritical Fluid Chromatography (UHPSFC): with a Feasibility Study for Detection in Milk

Nine widely used veterinary sulfonamide drugs were baseline separated (R _s ≥1.5) in just over 4 min using a 3 × 100 mm, 1.8 μm RX-Sil column, with 9.2 % methanol in carbon dioxide, at 110 bar and 30 °C, with direct UV detection at 260 nm using a 3 mm, 2 μL tapered flow cell. Pressure drop was only 172 bar. Optimization was difficult due to the similarity in structures. Small changes in modifier concentration, temperature and pressure, each tended to improve the resolution of some peak pairs but degraded the resolution of others. There were four critical pairs, each responding differently to changes in conditions. Optimization was performed by plotting resolution between pairs as a function of modifier concentration first, temperature second, and outlet pressure third. Retention time was then minimized by changing flow rate. The estimated limit of quantitation (LOQ, S/N >10), for direct injections, was ≈200–400 ng/g of each, inadequate for regulatory requirements. Solid phase extraction (SPE) attempted to pre-concentrate samples spiked with sulfamethazine by ≈20:1. From water, the limit of detection (LOD) was ≈2.7 ng/mL with LOQ ≈9 ng/mL using UV at 260 nm. The LOD for milk was 6.2 ng/mL, and LOQ was 20.1 ng/mL. A better pre-concentration step or a more sensitive detector such as MS–MS is required. Even with these inadequacies, SFC was shown to be a feasible, faster, “greener” alternative to HPLC for the separation of these drugs.     

Separation of 9 Sulfonamide Drugs in ≈4 Min by Ultra-High Performance Supercritical Fluid Chromatography (UHPSFC): with a Feasibility Study for Detection in Milk

Nine widely used veterinary sulfonamide drugs were baseline separated (R _s ≥1.5) in just over 4 min using a 3 × 100 mm, 1.8 μm RX-Sil column, with 9.2 % methanol in carbon dioxide, at 110 bar and 30 °C, with direct UV detection at 260 nm using a 3 mm, 2 μL tapered flow cell. Pressure drop was only 172 bar. Optimization was difficult due to the similarity in structures. Small changes in modifier concentration, temperature and pressure, each tended to improve the resolution of some peak pairs but degraded the resolution of others. There were four critical pairs, each responding differently to changes in conditions. Optimization was performed by plotting resolution between pairs as a function of modifier concentration first, temperature second, and outlet pressure third. Retention time was then minimized by changing flow rate. The estimated limit of quantitation (LOQ, S/N >10), for direct injections, was ≈200–400 ng/g of each, inadequate for regulatory requirements. Solid phase extraction (SPE) attempted to pre-concentrate samples spiked with sulfamethazine by ≈20:1. From water, the limit of detection (LOD) was ≈2.7 ng/mL with LOQ ≈9 ng/mL using UV at 260 nm. The LOD for milk was 6.2 ng/mL, and LOQ was 20.1 ng/mL. A better pre-concentration step or a more sensitive detector such as MS–MS is required. Even with these inadequacies, SFC was shown to be a feasible, faster, “greener” alternative to HPLC for the separation of these drugs.