Determination of monohydroxylated metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) from wastewater-treatment plants

A high-performance liquid chromatography separation coupled with mass spectrometry via an electrospray interface is proposed for the determination of the hydroxylated derivatives of polycyclic aromatic hydrocarbons (OH-PAHs) in treated and untreated wastewaters and suspended solids from sewage treatment plants (STPs). The developed SPE procedure was applied to spiked wastewater samples, with recovery yields (1000?mL; 100?ng?L^?1 spiking level) in the 65–87% (RSD: 6–12%) range for the selected OH-PAHs. The limits of detections ranged between 0.3 and 3.2?ng?L^?1, depending on the selected compound and on the investigated matrix. The proposed method was applied to the determination of the selected analytes in real samples from a sewage-treatment plant (STP). The investigated OH-PAHs were detected mainly in the particulate fraction. The exhibited mean concentrations of positive samples (as the sum of dissolved and particulate matter) in the STP final effluent ranged from 15 to 68?ng?L^?1.     

Solid-phase extraction with C30 bonded silica for analysis of polycyclic aromatic hydrocarbons in airborne particulate matters by gas chromatography-mass spectrometry

A solid-phase extraction (SPE) method using triacontyl bonded silica (C30) as sorbent was developed for the determination of 16 US Environmental Protection Agency polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matters quantitatively by gas chromatography-mass spectrometry (GC-MS). Optimization experiments were conducted using spiked standard aqueous solution of PAHs and real airborne particulates samples aiming to obtain highest SPE recoveries and extraction efficiency. Factors were studied in SPE procedures including the concentration of organic modifier, flow rate of sample loading and elution solvents. The ultrasonication time and solvents were also investigated. Recoveries were in the range of 68-107% for standard PAHs aqueous solution and 61-116% for real spiked sample. Limits of detection (LODs) and limits of quantification (LOQs) with standard solution were in the range of 0.0070-0.21 microgL(-1) and 0.022-0.67 microgL(-1), respectively. The optimized method was successfully applied to the determination of 16 PAHs in real airborne particulate matters.     

Simultaneous liquid chromatographic determination of 39 polycyclic aromatic hydrocarbons in indoor and outdoor air and application to a survey on indoor air pollution in Fuji, Japan

An analytical method was established for the simultaneous determination of 39 polycyclic aromatic hydrocarbons (PAHs) in air. The method was applied to a survey of gaseous and particulate PAHs in household indoor air. The survey was performed in 21 houses in the summer of 1999 and in 20 houses in the winter of 1999-2000 in Fuji, Japan. Thirty-eight PAHs were determined in indoor and outdoor air in the summer, and 39 PAHs were determined in indoor and outdoor air in the winter. The concentrations of gaseous PAHs in indoor air tended to be higher than those in outdoor air in the summer and winter. The concentrations of particulate PAHs in indoor air were the same as or lower than those in outdoor air in the summer and winter. PAH profiles, correlations between PAH concentrations, and multiple regression analysis were used to determine the factors affecting the indoor PAH concentrations. These results showed that gaseous PAHs in indoor air were primarily from indoor emission sources, especially during the summer, and that indoor particulate PAH concentrations were significantly influenced by outdoor air pollution.     

An investigation of calibration materials for the measurement of metals in ambient particulate matter on filters by LA-ICP-MS

Three different types of simple and low-cost calibration material for the measurement of the metals content of ambient particulate matter (PM) on filters using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) have been compared: cellulose ester filters spiked with multi-element calibration solutions, pellets of compressed ambient particulate matter certified reference material (CRM), and powdered ambient particulate matter CRM adhered to a surface. Elements determined were As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn, each at approximate levels of 1000?ng per filter. Blank filters spiked with multi-elemental standards were found to be significantly more reproducible and repeatable than materials based on powdered reference materials. However, a comparison of these spiked filters with real samples of ambient PM showed that the analytical sensitivities obtained per mass of analyte were significantly different. It is concluded that the spiked filters could act as very effective quality control standards correcting, to within 1%, drifts in LA-ICP-MS measurements of up to 10%, or as indirect calibration materials supported by additional measurements using traditional wet chemical techniques.     

复合免疫亲和柱-高效液相色谱法同时测定谷物及其制品中9种真菌毒素

建立了复合免疫亲和柱-在线光化学衍生-高效液相色谱同时测定谷物及其制品中9种真菌毒素的检测方法。以乙腈-水（80：20,v/v）混合溶液提取样品中9种真菌毒素,提取液经自制真菌毒素复合免疫亲和柱净化,采用高效液相色谱进行分离,在线光化学衍生后进入荧光检测器测定,外标法定量。结果表明,9种真菌毒素在相应浓度范围内线性关系良好,相关系数均大于0.999;在低、中、高3个不同加标浓度下,9种真菌毒素的回收率均大于80%,相对标准偏差（RSD）为1.0%~5.6%;方法的检出限（LOD）为0.02~5.00 μg/kg,定量限（LOQ）为0.07~16.70 μg/kg。该方法具有重现性好、灵敏度高、结果准确的特点,适用于谷物及其制品中9种真菌毒素残留的分析检测。     

疏水整体柱在线固相萃取与高效液相色谱-串联质谱联用测定牛肝中5种阿维菌素类药物残留

建立了牛肝中5种阿维菌素类药物残留的疏水整体柱在线固相萃取结合高效液相色谱-串联质谱测定的方法。以疏水的聚(甲基丙烯酸丁酯-乙二醇二甲基丙烯酸酯)整体柱(10 mm×2.1 mm)作为固相萃取介质,考察了上样流动相和洗脱流速对阿维菌素类药物的萃取效果,优化了梯度洗脱流动相的种类及质谱条件。方法在1~100 μg/L范围内线性关系良好(r>0.995),定量限为5 μg/kg。在5、10、50、100 μg/kg添加水平的回收率为77.4%~98.4%,日内和日间相对标准偏差分别为4.46%~8.03%和4.79%~8.68%,并且该柱反复使用400次后未发现萃取效率降低。结果表明,该整体柱对牛肝中5种阿维菌素类药物能够有效萃取,并且可以重复使用。该方法简单,自动化程度高,可应用于常规阿维菌素类药物残留分析。     

Determination of niacin in infant formula and wheat flour by anion-exchange liquid chromatography with solid-phase extraction cleanup

Niacin content must be included on food labels of infant formula products and bakery products containing enriched flour. Liquid chromatographic (LC) determination of niacin in complex food matrixes is complicated by the presence of endogenous compounds that absorb at the commonly used wave-length of 260 nm. Also, the presence of particulate matter in the standard sulfuric acid extraction procedure results in reduced life of LC columns and precolumns. A simple, rapid, solid-phase extraction (SPE) procedure for separation and cleanup of niacin from a complex food matrix digest has been developed. By using a vacuum manifold with the SPE column system, multiple samples can be processed quickly and efficiently for LC analysis, compared with gravimetric column cleanup. Sulfuric acid sample digest is passed over an aromatic sulfonic acid cation-exchange (ArSCX-SPE) or a sulfonated Florisil SPE column. Niacin is eluted with 0.25M sodium acetate-acetic acid, pH 5.6 buffer in vacuo. LC chromatograms of the resulting eluate are free of interference from other components absorbing at 260 nm at the retention time of niacin. Validation of the method was obtained from agreement of analytical results on available reference materials. For both SPE methods, values for niacin in SRM 1846 Infant Formula (milk-based powder) were within uncertainty ranges of the certified value. Use of several calibration procedures (the LC computer program, a peak area response graphic standard curve, or the method of standard additions) with both SPE procedures resulted in niacin values for 3 RM-Wheat Flours (not certified for niacin) in agreement (90-105%) with their respective values reported in the literature. Several commercial wheat flours showed a broad 260 nm interference, resulting in high niacin values. Niacin recoveries from spiked soy-based liquid infant formulas ranged from 95-107% with the ArSCX-SPE column. Calibration curves of niacin were linear up to 400 micrograms/mL, with a detection limit of 0.2 microgram/mL.     

Surface water preparation procedure for chromatographic determination of polycyclic aromatic hydrocarbons and polychlorinated biphenyls

A new sample preparation procedure for the analysis of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in water containing suspended particulate matter (SPM) has been developed. A specially designed filtration vessel coupled directly to an SPE cartridge was used for this purpose. SPM separation and analyte isolation/concentration were carried out in a single step. Both the SPE cartridge and the suspended matter collected on the filter were solvent extracted, and analyte recoveries were determined. Analyte recoveries from the filtrate ranged from 64 to 100% of the spiked amount for PAHs with the highest aqueous solubilities, and did not exceed 20% for those with the lowest solubilities. Total recoveries of PAHs from surface water containing 21 mg l(-1) SPM ranged from 65 to 121%. PCB recoveries from the particulate matter reached over 10% of the spiked amount, while those from the filtrate ranged from 20 to 57%. Total PCBs recoveries ranged from 34 to 69%.     

Simple solid-phase extraction method for determination of polychlorinated biphenyls and selected organochlorine pesticides in human serum

A simple off-line solid-phase extraction (SPE) method for isolation of polychlorinated biphenyls (PCBs) and selected organochlorine pesticides (OCPs) from human serum has been developed. The procedure includes denaturation of serum proteins by a mixture of water-1-propanol, application of the sample by aspiration twice repeatedly through the SPE column and elution with a mixture of n-hexane-dichlormethane. After final clean-up the compounds of interest were analysed by gas chromatography with micro-electron capture detection (GC-microECD). The recoveries achieved for PCB congeners using spiked porcine serum samples were 99-120% and for OCPs 88-115%. Relative standard deviations (RSD) ranged from 3 to 7%. The method was applied to real human serum samples and the recoveries of analytes in the serum were proportionally recalculated considering the recovery of the internal standard PCB-174. PCB-103 served as a syringe standard to correct volume of samples analysed. The aim of this study was to develop an effective off-line SPE procedure by optimization of existing SPE methods to supply laborious, solvent- and time-consuming liquid-liquid extraction (LLE) in routine analytical process.     

Microwave assisted extraction of polycyclic aromatic hydrocarbons from atmospheric particulate samples

For several years, microwave assisted extraction (MAE) was applied to extract organic compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, etc., from soils, sediments and standard reference materials. Very few authors applied this methodology for the extraction of PAHs from atmospheric particulate matter. In the present study, MAE of polycyclic aromatic hydrocarbons with hexane/acetone (1:1) from real atmospheric particulate samples was investigated and the effect of microwave energy and irradiation time studied. The yields of extracted compounds obtained by microwave irradiation were compared with those obtained using traditional Soxhlet extraction. MAE was evaluated using spiked real atmospheric particulate samples and two standard reference materials. Analytical determinations of PAHs were carried out by high performance liquid chromatography (HPLC) with ultraviolet and fluorescence detection. The best recoveries were achieved with a microwave energy of 400 W and an irradiation time of 20 min.     

Determination of estrogens and their metabolites in water using C30 SPE-LC-MS

Triacontyl bonded silica (C(30)) material was applied as solid-phase extraction (SPE) sorbent and an SPE-LC-MS method was established for the determination of eight estrogens and their metabolites in water samples. Compared to commercial C(18) SPE cartridge, the performance of C(30) was evaluated in various important SPE conditions, such as sorbent mass, elution solvent and its volume, loading flow rate, and sample loading volume. The results showed a superior performance of C(30)-C(18) by the shorter treatment time and fewer required elution solvent. In the optimum conditions, the results showed good recoveries (80.5-109.4%), excellent linear relationships (0.02-1 ng/mL, except 2-MeO-E(2)), high precisions (lower than 10.0% RSD for both low and high spiked concentration), and low LODs (1-16 ng/L). Method validation using C(30) packed cartridge was also testified with spiked real water samples, including tap water and river water. Satisfy results demonstrated the feasibility of C(30) SPE to the analysis for real environmental waters.     

在线固相萃取-液相色谱法直接测定水中超痕量多环芳烃

建立了在线固相萃取-液相色谱直接测定水体中16种超痕量多环芳烃（PAHs）的方法。水样经高速离心后，加入适量甲醇，配制成40%（体积分数）甲醇水溶液，直接进样2 mL至在线固相萃取流路，进行萃取富集，再通过阀切换将洗脱的PAHs转移至分析流路进行分离检测。16种PAHs在各自范围内线性关系良好，相关系数均大于0.996；方法的检出限为0.14~12.50 ng/L，其中苯并[a]芘（B（a）P）的检出限为0.38 ng/L。实际水样在10、40和200 ng/L加标水平下的加标回收率为76.1%~134.9%，RSD为0.3%~16.6%。B（a）P在1 ng/L加标水平下的回收率为71.8%~92.7%，RSD为3.9%。结果表明，该方法操作简单，灵敏度高，溶剂消耗量少，可满足水样中PAHs，尤其是B（a）P的超痕量分析要求。     

Sequential extraction procedure for speciation of inorganic cadmium in emissions and working areas

A sequential extraction procedure for separating and concentrating soluble Cd(II) salts, CdO, Cd(0), CdS, CdSe and cadmium-aluminosilicates, has been developed for the cadmium speciation in samples such as particulate matter in emissions and working areas. The proposed procedure has been tested first on synthetic samples prepared in a laboratory with the different cadmium salts, then also in the presence of atmospherical particulate matter sampled in a laboratory of the Department of Analytical Chemistry, previously checked for the absence of cadmium. Finally the speciation was tested on particulate matter collected near the emission of a power plant fed by coal, after emission's treatment by electrostatic precipitator: matrix spiking and recovery analyses have been evaluated and the repeatability of the cadmium speciation was assessed by performing multiple analyses of the spiked samples. Quantitative determinations have been made by FAAS and GFAAS through the standard additions method.     

Development and validation of a SPE-GC-MS method for the determination of pesticides in surface water

A method for analysis of 20 commonly used pesticides in surface water based on solid-phase extraction and gas chromatography-mass spectrometry was proposed. During method development the key parameters that can affect SPE extraction and determination such as selection of efficient SPE sorbent, pH of water sample, type and volume of elution solvent, breakthrough volume and matrix effects were investigated. The method was validated using spring water spiked with appropriate concentration of pesticides. The obtained correlation coefficients were in range 0.9972–1.000, limits of detection (LOD) were 0.001–0.5?µg?L^?1 and the limits of quantification (LOQ) were 0.005–1?µg?L^?1 depending on a pesticide. Much higher LOD (20?µg?L^?1) and LOQ (50?µg?L^?1) values were obtained for bentazone. The influence of matrix was assessed using real water samples spiked with appropriate concentration of pesticide standards solution. Both signal enhancement and suppression were observed, depending on a pesticide, therefore standard addition method was used for pesticides determination. The developed method was applied on real water samples taken in close vicinity of agricultural fields. Many of the targeted pesticides were found in the samples and the results are presented in this article.     

Rapid determination of chlorinated pesticides in fish by freezing-lipid filtration, solid-phase extraction and gas chromatography-mass spectrometry

An analytical method has been developed for measuring 24 chlorinated pesticides in fish tissue samples. Extraction of chlorinated pesticides was carried out by ultrasonication using an acetone-n-hexane (5:2, v/v) mixture. Most of the lipids in the extract were eliminated by freezing-lipid filtration, prior to solid-phase extraction (SPE) cleanup. During freezing-lipid filtration, about 90% of the lipids extracted from the fish samples were easily removed without any significant losses of chlorinated pesticides. For purification, SPE using Florisil was shown to be more effective than silica. Quantification was performed using gas chromatography-mass spectrometry in the selected ion monitoring mode. Spiking experiments were carried out to determine the recovery, precision, and limits of detection (LODs) of the method. The overall recovery was above 80% in the spiked fish tissue sample at 100 ng/g level. The detection limits for chlorinated pesticides were ranged from 0.5 to 5 ppb, except for endosulfan I and II which was 20 ppb. The newly developed method is demonstrated to give efficient recoveries and LODs for detecting chlorinated pesticides spiked into fish tissue with high lipid content.     

高效液相色谱-串联质谱法测定食品中多杀菌素A和D的残留量

建立了食品中多杀菌素(spinosyn) A和D残留的液相色谱-串联质谱(HPLC-MS/MS)检测方法。甘蓝等食品样品经乙腈-水(50:50, v/v)提取、HLB固相萃取柱净化后,采用HPLC-MS/MS进行检测分析,利用外标法定量。质谱分析采用电喷雾电离,正离子扫描,多反应监测模式。结果表明,柱净化后无明显的基质效应,多杀菌素在1～20 μg/L内具有较好的线性关系,其相关系数可达0.9999;样品中添加1～10 μg/kg的多杀菌素,其回收率为76.2%～114.0%,相对标准偏差(n=10)小于10%;检出限(信噪比（S/N）=3): 多杀菌素A为0.2 μg/kg,多杀菌素D为0.5 μg/kg;定量限(S/N=10): 多杀菌素A为0.5 μg/kg,多杀菌素D为1.0 μg/kg。在最佳实验条件下,对来自福建厦门的969份食品样品进行了检测,其中15份样品检测结果呈阳性。实验结果表明,该方法提取效果好,具有良好的灵敏度、回收率和重复性。     

Determination of seven nitrobenzene compounds in mainstream cigarette smoke with heart-cutting two-dimensional gas chromatography

A heart-cutting two-dimensional gas chromatography (GC) method was developed for the determination of nitrobenzene compounds (NBCs) in mainstream cigarette smoke. For the method, the particulate matter of cigarette smoke was extracted with cyclohexane, purified with a silica solid-phase extraction (SPE) cartridge and analyzed by heart-cutting two-dimensional GC equipped with two electron capture detectors. The heart-cutting two-dimensional GC was achieved by a single-column GC oven equipped with a microfluidic pressure balanced device (Deans switch). Two-dimensional GC was compared to single-dimensional GC and found to be clearly better for the separation of seven NBCs from a complex smoke matrix. The limits of detection ranged from 1.28 to 9.83 ng/mL, spiked recoveries were between 88.3 and 106.8% and relative standard deviation ranged from 2.79 to 12.78%. The NBCs yields of six kinds of Chinese and international cigarettes brands, which were all smoked according to two smoking protocols (International Organization for Standardization and Health Canada Intense smoking regimens), were determined and compared.     

Graphene as an efficient sorbent for the SPE of organochlorine pesticides in water samples coupled with GC–MS

The determination of organochlorine pesticides in water samples, which are harmful to humans, is very important for environmental risk assessment. Based on the excellent adsorption properties of graphene, an SPE coupled with GC–MS method for the monitoring of organochlorines (four hexachlorcyclohexanes and four dichlorodiphenyltrichloroethanes) was developed. Owing to the hydrophobic interaction and π–π stacking interaction between the analytes and graphene, the analytes quantitatively adsorbed onto the graphene‐based SPE cartridge were eluted by ethyl acetate for analysis. Several parameters influencing the analytical performance, such as the kind of elution, sample volume, reusability of the cartridge, have been investigated in detail. Under the optimal conditions, detection of limits of 1.95–9.38 ng/L, recoveries of 83.9–107.3% at two spiked concentration levels (0.1 and 10 ng/mL) and RSDs in the range of 2.9–7.4% for real water samples were obtained for all the analytes. This work reveals the great potential of graphene in sample preparation procedures.     

Polycyclic aromatic hydrocarbon analysis in different matrices of the marine environment

Polycyclic aromatic hydrocarbons (PAHs) were determined in marine samples of various types, i.e. seawater, sediment and mussel homogenate samples. The samples were spiked with standard PAH mixtures in both polar (acetonitrile) and non-polar (i-octane) solvents, then extracted. Extraction from seawater was performed by liquid/liquid extraction to hexane (LLE) and with solid phase extraction (SPE) discs. The water samples were filtered and unfiltered seawater, and redistilled water for comparison. The discs with PAHs adsorbed from water samples, and also the sediment and mussel homogenate samples, were extracted with acetonitrile by sonication. PAHs in the disc extracts and from the LLE were cleaned-up using TLC and next determined by GC/MS/IT (with ion-trap) and HPLC-DAD/UV. The analytical procedures were verified with deuterated PAH standard mixtures. The large differences in PAH recoveries (from 12 to 86% for sum, and from 3 to 135% for particular PAHs) do not depend solely on the type of matrix and analytical procedure applied (e.g. standard solvent, volume of evaporated sample), but also on the concentration and molecular structure of the analyte. Usually, only a fraction of each PAH content in the matrix is determined, depending on the particulate matter in seawater and the sorption properties of the solid matrix. The recoveries of deuterated PAHs are higher than those of non-deuterated compounds.     

Synthesis,characterization, and application of griseofulvin surface molecularly imprinted polymers as the selective solid phase extraction sorbent in rat plasma samples

In present study, an investigation was carried out to develop and validate an analytical method for the selective extraction and determination of griseofulvin (GSF) from plasma samples. For this purpose, a rational approach was made to synthesize and characterize the surface molecularly imprinted polymers (SMIPs). The SMIPs were utilized as solid phase extraction (SPE) sorbents. The SMIPs were prepared by using GSF as template molecule on the surface of modified silica particles through a non-covalent technique. The particles demonstrated high adsorption capacity (119.1 µg/mL), fast adsorption equilibrium time (30 min) and good recognition selectivity for the template drug. The scanning electron microscopy and infrared spectroscopy were used to explain the structural and morphological characteristics of the SMIPs and surface non-imprinted polymers. The SPE method was combined with HPLC for plasma analysis. The method validation results demonstrated that the established method possessed good linearity for GSF ranging from 0.1 to 50 µg/mL (R² = 0.997). The limit of detection for this method was 0.02 µg/mL for rat plasma samples. The recoveries of GSF from spiked plasma samples were (90.7–97.7%) and relative standard deviations were (0.9–4.5%). Moreover, the SMIPs as selective SPE sorbent can be reused more than 8 times which is a clear advantage over commercial SPE sorbents. Finally, the usefulness of the proposed strategy was assessed by extraction and detection of GSF in real rat plasma samples.