高效液相色谱-串联质谱内标法同时测定水产品中15种喹酮类药物残留量

建立了水产品中15种喹诺酮类药物(QNs)残留量的高效液相色谱-串联质谱(HPLC-MS/MS)测定方法。以氘代试剂为内标,样品经酸性乙腈萃取后,用正己烷脱脂,旋转蒸发浓缩,采用HPLC-MS/MS选择反应监测(SRM)正离子模式测定,内标法定量。可同时对水产品中的15种QNs进行定性和定量测定。15种QNs的检出限(S/N=3)为1.0μg/kg,定量限(S/N=10)为2.0μg/kg;在10.0～200.0ng/mL时峰强度与质量浓度的线性关系良好(r0.99)。方法的平均回收率范围为66%～121%。该法简便快捷,分析成本低,在一定程度上实现了药物残留的快速检测。     

New analytical procedure based on a cellulose bag and ionic exchanger with p-aminobenzoic acid groups for differentiation of labile and inert metal species in aquatic systems

A new procedure was developed for the in situ characterization of the lability of metal species in aquatic systems by using a system equipped with a diffusion membrane and cellulose organomodified with p-aminobenzoic acid groups (DM-Cell-PAB). To this end, the DM-Cell-PAB system was prepared by adding cellulose organomodified with p-aminobenzoic acid groups (Cell-PAB) to pre-purified cellulose bags. After the DM-Cell-PAB system was sealed, it was examined in the laboratory to evaluate the influence of complexation time, mass of exchanger, pH, metal ions (Cu, Cd, Fe, Mn, and Ni), and concentration of organic matter on the relative lability of metal species. It was found that the pH and kinetics strongly influence the process of metal complexation by the DM-Cell-PAB system. At all pH levels, Cd, Mn, and Ni showed lower complexation with Cell-PAB resin than Cu and Fe metals. Note that relative lability of metals complexed to aquatic humic substances (AHS) in the presence of Cell-PAB resin showed the following order: Cu≅Fe≫Ni>Mn=Cd. The results presented here also indicate that increasing the AHS concentration decreases the lability of metal species by shifting the equilibrium to AHS–metal complexes. Our results indicate that the system under study offers an interesting alternative that can be applied to in situ experiments for differentiation of labile and inert metal species in aquatic systems.     

Analysis of ultratrace triorganotin compounds in aquatic organisms by using capillary electrophoresis-inductively coupled plasma mass spectrometry

A microwave-assisted extraction used to extract trace triorganotin from aquatic organisms and a sensitive analytical method for the determination of ultratrace triorganotin (namely trimethyltin, triethyltin, tripropyltin and tributyltin) with capillary electrophoresis-inductively coupled plasma mass spectrometry were firstly described in this study. The extraction method is simple, effective and can be used to extract trace triorganotin in aquatic organisms within several min. The analytical method has a much lower detection limit of 0.2-0.7 ng Sn/mL for triorganotin compounds, and can be used to determine trace triorganotin in aquatic organisms directly without any derivatization and preconcentration. Using above methods, we have successfully determined trimethyltin, triethyltin, tripropyltin and tributyltin in dried Mya arenaria Linnaeus and Corbicula fluminea within 17 min with a recovery of 93-104% and a RSD (relative standard deviation, n = 6) of 2-5%. Our results showed that dried M. arenaria Linnaeus contained an extremely high tributyltin of 5.1 μg Sn/g dried weight, indicating that it may be a good biomarker for the organotin pollution in ocean.     

Fast isolation of hydrophobic organic environmental contaminants from exposed semipermeable membrane devices (SPMDs) prior to GC analysis

Semipermeable membrane devices (SPMD) represent a passive sampling technology that is becoming widely used for monitoring of surface waters pollution. While "classic" procedures employ dialysis to recover target compounds from exposed SPMDs, in the present study analytes were isolated from cut membrane together with sequestering medium (triolein) using hexane as an extraction solvent. This approach allowed us to reduce the time needed for accomplishment of isolation step from 48 h to only 1 h. Automated gel permeation chromatography (GPC) clean-up is employed in the following step to separate triolein from analytes fraction. Musk compounds (MCs), polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs) and several other persistent organochlorine compounds (OCs) were determined in the respective fraction by GC method employing selective detectors (MSD, ECD). As shown in a series of analyses of SPMDs deployed in various aquatic ecosystems, high recoveries and good repeatability of results together with a possibility to obtain the information on the pollution of sampling site at the day of sample arrival to laboratory make this newly implemented procedure an interesting alternative to time consuming dialysis.     

Multi-detection method for five common microalgal toxins based on the use of microspheres coupled to a flow-cytometry system

Freshwater and brackish microalgal toxins, such as microcystins, cylindrospermopsins, paralytic toxins, anatoxins or other neurotoxins are produced during the overgrowth of certain phytoplankton and benthic cyanobacteria, which includes either prokaryotic or eukaryotic microalgae. Although, further studies are necessary to define the biological role of these toxins, at least some of them are known to be poisonous to humans and wildlife due to their occurrence in these aquatic systems. The World Health Organization (WHO) has established as provisional recommended limit 1 μg of microcystin-LR per liter of drinking water. In this work we present a microsphere-based multi-detection method for five classes of freshwater and brackish toxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), anatoxin-a (ANA-a), saxitoxin (STX) and domoic acid (DA). Five inhibition assays were developed using different binding proteins and microsphere classes coupled to a flow-cytometry Luminex system. Then, assays were combined in one method for the simultaneous detection of the toxins. The IC₅₀'s using this method were 1.9 ± 0.1 μg L⁻¹ MC-LR, 1.3 ± 0.1 μg L⁻¹ CYN, 61 ± 4 μg L⁻¹ ANA-a, 5.4 ± 0.4 μg L⁻¹ STX and 4.9 ± 0.9 μg L⁻¹ DA. Lyophilized cyanobacterial culture samples were extracted using a simple procedure and analyzed by the Luminex method and by UPLC–IT-TOF-MS. Similar quantification was obtained by both methods for all toxins except for ANA-a, whereby the estimated content was lower when using UPLC–IT-TOF-MS. Therefore, this newly developed multiplexed detection method provides a rapid, simple, semi-quantitative screening tool for the simultaneous detection of five environmentally important freshwater and brackish toxins, in buffer and cyanobacterial extracts.     

Occurrence and spatial distribution of statins,fibrates and their metabolites in aquatic environments

Due to widespread occurrence of lipid lowering drugs such as statins, fibrates and their metabolites in the aquatic environments, there is a worldwide growing concern in their role in water quality and aquatic biota. However, this concern is limited by ability to address their occurrence, distribution, fate and eco-toxicological effects. This study focuses on the quantification of the levels of statins, fibrates and their metabolites in the aquatic environments using Ultra-High Performance Liquid Chromatography coupled to high resolution quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). The developed UHPLC–QTOF–MS based method was successfully applied to the analysis of statins, fibrates and metabolites in real water samples collected from Daspoort WWWs influent and effluent and Apies River. A series of statin compounds (mevastatin, simvastatin, pravastatin, rosuvastatin, fluvastatin, atorvastatin), fibrates (gemfibrozil, fenofibrate) and the corresponding metabolites (clofibric and fenofibric acids) were detected and quantified in the range of 0.56–19.90 µg/L in both waste and River water samples. In general, the results of the present study are an indication of pollution hazards from wastewater treatment processes and these levels poses a huge risk to the growth and reproduction of aquatic organisms. Thus, regulating the limit levels of statins, fibrates and metabolites in any type of water is paramount as it will provide the vital information on the toxic risks associated with organic pollutants of pharmaceutical origin.     

凝胶渗透色谱-超高效液相色谱-串联质谱法测定水产品中多种同化激素残留

结合凝胶渗透色谱净化技术,建立了超高效液相色谱-串联质谱法测定水产品中6种同化激素的残留。样品经叔丁基甲醚提取,以乙酸乙酯-环己烷(1+1)溶液为流动相进行凝胶渗透色谱净化,用C18固体吸附剂净化,以C18色谱柱分离,采用电喷雾正离子源、多反应监测模式检测,外标法定量。6种激素的线性范围均为0.5~50μg·L-1,测定下限(10S/N)在0.20~1.50μg·kg-1之间。对空白样品进行加标回收试验,回收率在81.7%~90.8%之间,日间精密度(n=5)在5.8%~7.9%之间。     

冷冻去脂-固相萃取-气相色谱法快速测定水产品中硫丹、硫丹硫酸酯和溴氰菊酯残留量

建立了气相色谱快速测定水产品中硫丹、硫丹硫酸酯和溴氰菊酯的残留量的方法。样品经过V(丙酮)∶V(正己烷)=1∶1提取,冷冻去除脂肪后,再用中性氧化铝SPE柱净化,然后用GC-μECD测定,外标法定量。对样品的提取和净化进行了研究和优化。目标化合物在0.005~0.1 mg/L范围内线性良好,相关系数为0.9994~0.9997。在0.005~0.02 mg/kg范围内,平均回收率在78.3%~89.2%,相对标准偏差为4.2%~9.7%。方法可用于水产品中硫丹、硫丹硫酸酯和溴氰菊酯残留量的检验。     

高效液相色谱-电感耦合等离子质谱法分析水产品中有机锡的形态

建立了水产品中三甲基锡(TMT)、一丁基锡(MBT)、二丁基锡(DBT)、三丁基锡(TBT)、一苯基锡(MPhT)、二苯基锡(DPhT)、三苯基锡(TPhT)7种有机锡化合物的高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)的分离检测方法.方法利用Eclipse Plus C18反相色谱柱对水产品中7种有机锡化合物进行分离,利用电感耦合等离子体质谱对锡元素进行检测,外标法定量测定水产品中7种有机锡化合物的含量.研究采用30 mL 30％乙酸-甲醇提取液(V/V),低温超声萃取10 min后离心3 min,取上清液20 mL浓缩,用流动相定容至2 mL,以乙酸(0.2％三乙胺,V/V)-甲醇溶液为流动相,梯度洗脱,7种有机锡化合物在30 min内得到了有效分离.7种有机锡化合物标准曲线的线性相关系数大于0.995,检出限0.11 ～0.60 μg/kg.此前处理方法样品加标回收率为72.1％～ 111.7％.本方法操作简便,分离效果好,检出限低,适用于水产品中有机锡的检测.     

Separation and analysis of trace volatile formaldehyde in aquatic products by a MoO3/polypyrrole intercalative sampling adsorbent with thermal desorption gas chromatography and mass spectrometry

An in situ embedded synthesis strategy was developed for the preparation of a MoO₃/polypyrrole intercalative sampling adsorbent for the separation and analysis of trace volatile formaldehyde in aquatic products. Structural and morphological characteristics of the MoO₃/polypyrrole intercalative adsorbent were investigated by a series of characterization methods. The MoO₃/polypyrrole sampling adsorbent possessed a higher sampling capacity and selectivity for polar formaldehyde than commonly used commercial adsorbent Tenax TA. Finally, the MoO₃/polypyrrole adsorbent was packed in the thermal desorption tube that was directly coupled to gas chromatography with mass spectrometry for the analysis of trace volatile formaldehyde in aquatic products. Trace volatile formaldehyde from real aquatic products could be selectively sampled and quantified to be 0.43–6.6 mg/kg. The detection limit was achieved as 0.004 μg/L by this method. Good recoveries for spiked aquatic products were achieved in range of 75.0–108% with relative standard deviations of 1.2–9.0%.