Phase Extraction-high Performance Liquid Chromatography-tandem Research Articles

Determination of 42 antimicrobials in disinfection products by dispersive solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

Antimicrobials inhibit the growth and reproduction of microorganisms thereby alleviating skin and other problems caused by microorganisms. Antimicrobials are classified into different categories, including antibacterials, antifungals, and antivirals, among others, and include azoles, sulfonamides, tetracyclines, quinolones, and many other classes of synthetic and natural compound. The inappropriate or excessive use of antimicrobials can damage skin and other human organs and increase antimicrobial resistance. Relevant regulations and standards clearly state that antimicrobials are prohibited for use as ingredients in disinfection products. However, since antimicrobials enhance the disinfection or antibacterial effect of a product, with a significant short-term effect, antimicrobials are occasionally illegally added to disinfectant products, including those intended for human use. Therefore, establishing testing methods that provide technical support for enforcing regulations is an urgent objective. Herein, a method was established for the analysis of 42 antimicrobials in disinfection products, that is applicable to common types of disinfection-product matrix, including creams, gels, and aqueous solutions, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with dispersive solid phase extraction. The 42 antimicrobials comprise antibacterials, antifungals, and antivirals, and include seven sulfonamides, ten quinolones, three lincosamides, five tetracyclines, three macrolides, eight azoles, three purine nucleoside analogs, one furan, one nonpolyene antifungal, and one steroid. Briefly, 0.2 g of a sample was first dispersed in 2 mL of water and then extracted with 10 mL of 0.5% formic acid in acetonitrile, with 3 g of anhydrous Na2SO4 added to remove water. After centrifugation, 5 mL of the supernatant was cleaned using dispersive solid phase extraction with EMR-Lipid as the adsorbent. Lipids, waxes, surfactants, and moisturizing lubricants are commonly used as cream and gel matrices. Matrix substances containing long carbon chains dissolved in acetonitrile were removed using the EMR-Lipid adsorbent. Target analytes were separated on a Poroshell 120 EC-C18 analytical chromatography column (150 mm×3.0 mm, 2.7 μm), with 0.1% formic acid in acetonitrile and 0.1% formic acid aqueous solution used as mobile phases under gradient-elution conditions. The target analytes in the test solution were detected in positive ionization (ESI+) and multi-reaction-monitoring (MRM) modes. Analytes were characterized in terms of their retention times and selected ions, and quantified using the external-standard method. The main factors affecting method response, recovery, and sensitivity, such as the extraction method and solvent, purification method and adsorbent, mobile phase, and MS conditions, were examined during sample pretreatment and instrumental analysis. The 42 antimicrobials were effectively separated under the optimized experimental conditions; the target compounds exhibited linear working curves in the 0.25-5.0 mg/kg concentration range, with correlation coefficients (r) greater than 0.99. Limits of detection (LODs) for the 42 antimicrobials were determined from the signal-to-noise ratios (S/N) of their chromatographic peaks. LODs of 0.03-0.10 mg/kg were determined for the three matrices using 0.2-g samples and 10-mL test solution. Recoveries of 80.3-109.8%, with relative standard deviations (RSDs) of less than 9.8%, were obtained by determining three levels of each target analyte added to the three blank matrices; this process was repeated for six parallel samples. The developed method was used to analyze antimicrobials in commercially available disinfection products, with two sample batches testing positive. The established method is simple, accurate, precise, and suitable for the rapid screening and quantification of antimicrobials in disinfection products. This study provides powerful technical support for regulating the illegal addition of related antimicrobials to disinfection products.

Occurrence and Risk of Organophosphate Flame Retardants in Multiple Urban Water of Beijing, China

Investigating the organophosphate flame retardants (OPFRs) concentration and attenuation in multiple water of Beijing would provide valuable insight into OPFR management and reduction; thus, 6 OPFRs were determined by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry to explore the pollution characteristics, and ecological risk of OPFRs. The results showed that 5 OPFRs were detected with a concentration ranging from ND to 394.77 ng/L except for tris(2,3-dibromopropyl) phosphate (TDBP). The chloroalkyl phosphate was the main compound and tris(chloropropyl) phosphate (TCPP) was the most abundant OPFRs with the highest concentration. The concentration of aryl-OPFRs in surface water and groundwater was much lower than that of chlorinated ones, and the concentration of chlorinated OPFRs in surface water was higher than that in groundwater. The treatment effect of chlorinated OPFRs including TCPP, TCEP, and TDCPP in STPs was negative. Ecological risk assessment showed that low risk of OPFRs for the organisms (algae, crustacean, and fish).

Determination of trace perfluorinated compounds in environmental water samples by dispersive solid- phase extraction-high performance liquid chromatography-tandem mass spectrometry using carbon nanotube composite materials

In this work, carbon nanotubes (CNTs) on silica rod (SiO2) composite materials were prepared to extract six perfluorinated compounds (PFCs) in real environmental water samples by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The as-synthesized sorbents, hereafter referred to as CNT@SiO2, were employed for dispersive solid-phase extraction (d-SPE). Perfluoroheptanoic acid (PFHpA), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctane sulfonate (PFOS), and perfluorodecanoic acid (PFDA) were selected as target analytes. The main extraction parameters were systematically optimized using the single-factor optimization method. The optimum adsorption parameters were as follows: adsorption time of 30 min, sorbent amount of 10 mg, pH 6 and NaCl concentration of 1.7 mol/L for sample solution, and 4 mL acetone as desorption solvent, desorption for 4 min. LC-triple quadrupole MS was conducted to quantify the selected PFCs in water samples. The mobile phase was 5 mmol/L ammonium acetate and methanol, the flow rate was set to 0.4 mL/min, the column temperature was set to 40 ℃, and the injection volume was 5.0 μL. The chromatographic separation system was equipped with a Kinetex C18 column (100 mm×2.1 mm, 1.7 μm). The mass spectrometer was operated with negative electrospray ionization in multi-reaction monitoring mode. CNT@SiO2 was prepared in five batches and used as the d-SPE sorbent, and the relative standard deviations (RSDs) of the PFC recoveries among these five batches ranged from 4.9% to 9.3%. The reusability of the CNT@SiO2 sorbent was assessed. After eight d-SPE cycles using the same sorbent, the RSDs of the PFC recoveries were 3.7%-8.2%. These results indicated that the sorbent had good stability and reusability for d-SPE. Excellent results were achieved under optimal extraction conditions. The method validation results indicated that the linear ranges were 0.4-1000 ng/L for PFNA, PFOS, and PFDA, 0.9-1000 ng/L for PFHpA, 0.7-1000 ng/L for PFHxS, and 0.6-1000 ng/L for PFOA. The correlation coefficients were 0.973-0.997. The limit of detection (LOD) and limit of quantification of the method were 0.10-0.26 ng/L and 0.33-0.87 ng/L, respectively. At 20 ng/L, the RSDs of the intra- and inter-day precisions were 2.73%-7.75% and 3.38%-8.21%, respectively. At 100 ng/L, the RSDs of the intra- and inter-day precisions were 2.95%-8.46% and 4.16%-9.14%, respectively. Finally, at 500 ng/L, the RSDs of the intra- and inter-day precisions were 2.51%-7.48% and 3.59%-9.63%, respectively. The developed method was applied to analyze six PFCs in tap water, barreled drinking water, and river water samples. PFOA and PFOS were determined in tap water at mass concentrations of 5.6 and 8.7 ng/L, respectively. No PFCs were found in barreled drinking water and river water. Satisfactory recoveries of 72.1%-109.6% at low, middle, and high spiking levels were also obtained. In conclusion, the d-SPE-LC-MS/MS method based on CNT@SiO2 composite sorbents is accurate and sensitive. The results of this study demonstrate that CNT@SiO2 is a good choice for the rapid and effective determination of PFCs from water samples. Further exploration of the use of CNT@SiO2 sorbents for the extraction and determination of trace organic pollutions in environmental samples is in progress.

Simultaneous determination of 22 antibiotics in environmental water samples by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

The widespread and frequent use of antibiotics to treat diseases or encourage animal growth has resulted in their persistence and accumulation in water, soil, and sediments. As a typical emerging pollutant in the environment, antibiotics have become an important research focus in recent years. Antibiotics are commonly found at trace levels in water environments. Unfortunately, the determination of various types of antibiotics, all of which exhibit different physicochemical properties, remains a challenging endeavor. Thus, developing pretreatment and analytical techniques to achieve the rapid, sensitive, and accurate analysis of these emerging contaminants in various water samples is an essential undertaking.In this paper, a solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method for the simultaneous determination of 22 antibiotics including 4 penicillins, 12 quinolones and 6 macrolides in environmental water samples was developed. Based on the characteristics of the screened antibiotics and sample matrix, the pretreatment method was optimized, focusing on the SPE column, pH of the water sample, and amount of ethylene diamine tetra-acetic acid disodium (Na2EDTA) added to the water sample. Prior to extraction, a 200 mL water sample was added with 0.5 g of Na2EDTA and pH-adjusted to 3 using sulfuric acid or sodium hydroxide solution. Water sample enrichment and purification were achieved using an HLB column. HPLC separation was carried out on a C18 column (100 mm×2.1 mm, 3.5 μm) via gradient elution with a mobile phase composed of acetonitrile and 0.15% (v/v) formic acid aqueous solution. Qualitative and quantitative analyses were performed on a triple quadrupole mass spectrometer in multiple reaction monitoring mode using an electrospray ionization source. The results showed correlation coefficients greater than 0.995, indicating good linear relationships. The method detection limits (MDLs) and limits of quantification (LOQs) were in the ranges of 2.3-10.7 ng/L and 9.2-42.8 ng/L, respectively. The recoveries of target compounds in surface water at three spiked levels ranged from 61.2% to 157%, with relative standard deviations (RSDs) of 1.0%-21.9%. The recoveries of target compounds in wastewater at three spiked levels were 50.1%-129%, with RSDs of 1.2%-16.9%. The method was successfully applied to the simultaneous determination of antibiotics in reservoir water, surface water, sewage treatment plant outfall, and livestock wastewater. Most of the antibiotics were detected in watershed and livestock wastewater. Lincomycin was detected in 10 surface water samples, with a detection frequency of 90%, and ofloxacin showed the highest contents (127 ng/L) in livestock wastewater. Therefore, the present method exhibits excellent performance in terms of MDLs and recoveries compared with previously reported methods. The developed method presents the advantages of small water sample volumes, wide applicability, and fast analysis times; thus, it can be considered a rapid, efficient, and sensitive analytical method with excellent potential for monitoring emergency environmental pollution. The method could also provide a reliable reference for formulating antibiotic residue standards. The results provide strong support for and an improved understanding of the environmental occurrence, treatment, and control of emerging pollutants.

Exposure assessment of polycyclic aromatic hydrocarbons in refined coal tar sealant applications.

Refined coal tar sealant (RCTS) emulsions are used to seal the surface of asphalt pavement. Nine of the 22 polycyclic aromatic hydrocarbons (PAHs) evaluated in this study are classified as known, probable, or possible human carcinogens. Exposure assessment research for RCTS workers has not been published previously. The overall objective of this study was to develop a representative occupational exposure assessment of PAH exposure for RCTS workers based on worksite surveys. The specific aims were to: 1) quantify full-shift airborne occupational exposures to PAHs among RCTS workers; 2) quantify workers' dermal exposures to PAHs; 3) quantify biomarkers of PAH exposure in workers' urine; 4) identify specific job titles associated with RCTS exposure; and 5) apply these results to a biological exposure index to assess risk of potential genotoxicity from occupational exposures. A total of twenty-one RCTS workers were recruited from three companies. Personal and area air samples were collected using a modification of NIOSH Method 5515. Dermal exposure was assessed by hand and neck wipes before and after shifts. Twenty-two PAHs were quantified via gas chromatography-mass spectrometry selected ion monitoring. Internal dose was estimated by quantifying select PAH metabolites in pre- and post-shift urine samples using on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. PAH levels in the worker breathing zones were highest for naphthalene, acenaphthene, and phenanthrene, with geometric means of 52.1, 11.4, and 9.8μg/m3, respectively. Hand wipe levels of phenanthrene, fluoranthene and pyrene were the highest among the 22 PAHs with geometric means of 7.9, 7.7, and 5.5μg/cm2, respectively. Urinary PAH biomarkers for naphthalene, fluorene, phenanthrene, and pyrene were detected in all workers and were higher for post-shift samples than those collected pre-shift. Urinary concentrations of the metabolite 1-hydroxypyrene were greater than the American Conference of Governmental Industrial Hygienists (ACGIH) Biological Exposure Index (BEI) for this metabolite in 89 percent of post-shift samples collected on the final day of the work week or field survey. Statistically significances were found between concentrations of fluorene, naphthalene, and phenanthrene in the breathing zone of workers and their corresponding urinary PAH biomarkers. Workers were placed in two work place exposure groups: applicators and non-applicators. Applicators had higher total PAH concentrations in personal breathing zone (PBZ) air samples than non-applicators and were more likely to have post-shift hand wipe concentrations significantly higher than pre-shift concentrations. Concentrations of post-shift urinary biomarkers were higher, albeit not significantly, for applicators than non-applicators. The exposure results from RCTS worker samples cannot be explained by proximal factors such as nearby restaurants or construction. Air and skin concentration levels were substantially higher for RCTS workers than previously published levels among asphalt workers for all PAHs. PAH profiles on skin wipes were more consistent with RCTS sealant product than air samples. Last day post-shift urinary concentrations of 1-hydroxypyrene greatly exceeded the ACGIH BEI benchmark of 2.5μg/L in 25 of 26 samples, which suggests occupational exposure and risk of genotoxicity. When pyrene and benzo[a]pyrene were both detected, concentration ratios from personal exposure samples were used to calculate the adjusted BEI. Concentrations of 1-hydroxypyrene exceeded the adjusted BEIs for air, hand wipes, and neck wipes in most cases. These results indicate the need to increase safety controls and exposure mitigation for RCTS workers.

Determination and level investigation of 45 hormones in edible bird's nest by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

建立了固相萃取-高效液相色谱-串联质谱(SPE-HPLC-MS/MS)同时测定食用燕窝中皮质激素、雌激素、雄激素及孕激素等5类45种激素的多残留分析方法。采用乙腈-乙酸乙酯(1∶1, v/v)超声辅助提取、亲水亲脂平衡固相萃取柱净化,甲醇洗脱。分别在正、负电喷雾电离源、多反应监测模式下检测45种激素。正离子模式下的流动相为乙腈-0.1%甲酸水溶液,负离子模式下的流动相为乙腈-水,色谱柱为Phenomenex Kinetex C18柱(100 mm×2.1 mm, 2.6 μm)。在优化条件下,45种激素在0.20~20.0 μg/L范围内线性关系良好,相关系数(R2)≥0.9990,方法的检出限(LOD)为0.04~0.70 μg/kg,定量限(LOQ)为0.16~2.00 μg/kg。按三水平(2.0、4.0、20.0 μg/kg)进行加标回收试验,氟米龙、布地奈德、醛固酮、醋酸氟轻松、炔雌醇的回收率为40.2%~63.6%,可对这5种激素进行定性分析,其余40种激素的平均加标回收率为72.2%~112.3%,相对标准偏差(RSD)为2.5%~11.6%,该方法可对40种激素进行准确定性定量,精密度好,灵敏度高,简便、快速。从2017~2021年,通过研究建立的方法对来自马来西亚、印度尼西亚、泰国和越南等国家的1021个燕窝样品进行监测,仅勃地酮、雄烯二酮、孕酮有检出(大于检出限),其他激素均小于检出限。孕酮检出率为100%,勃地酮、雄烯二酮检出率分别为79%和89%, 3种激素含量范围分别为0.097~3.58、0~0.096和0~1.77 μg/kg。与同为动物源性食品的鸡蛋、纯牛奶、乳制品相比,所有测定的鸡蛋样品中均检出雄烯二酮,含量比其他3类产品略高;勃地酮在4类产品中的含量差别不大,均为微量;孕酮含量在鸡蛋中最高,其次是纯牛奶,燕窝中含量最低。研究结果表明,食用燕窝带入的激素种类少,含量低,对健康影响小。

Analytical characterization of nucleotides and their concentration variation in drinking water treatment process

Nucleotides, as the basic building blocks of nucleic acids, widely exist in aqueous environment. In this study, we developed a solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) method for the analysis of 5′-adenosine monophosphate (AMP), 5′-uridine monophosphate (UMP), 5′-cytidine monophosphate (CMP) and 5′-guanosine monophosphate (GMP). The method achieved limits of detection (LODs) of 0.1–1.0 ng/L, and recoveries of 85–95% for the four tested nucleotides. The occurrence and concentrations of the four nucleotides in water from eight representative drinking water treatment and distribution systems in China were determined using this method. All four nucleotides were detectable in water treatment plant (WTP) influent and effluent, at concentrations of up to 30 ng/L and with occurrence frequency of around 90%. The concentrations of identified nucleotides increased 3–10 times after 10 km of water age in the water distribution system. Biological filters and coagulation increased the concentrations of nucleotides, conversely, active carbon, ozonation, and ultrafiltration membrane removed nucleotides in water. The effects of active carbon and coagulation were further confirmed using laboratory-controlled experiment. In addition, monochlorinated nucleotides were identified as the chlorination products of nucleotides.

Occurrence and Risk Assessment of Organophosphate Esters in Source Water of the Nanjing Section of the Yangtze River

We explored the pollution characteristics, spatial and temporal distribution, ecological risk, and human health risk of organophosphate esters (OPEs) in the source water of the Nanjing section of the Yangtze River. Thirteen OPEs were determined by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. The results showed that twelve OPEs were detected to different extents with total concentrations ranging from 85.21 to 1557.96 ng·L-1[excluding tris (2,3-dibromopropyl) phosphate]. Chloroalkyl phosphate was the main compound and tris(2-chloroethyl) phosphate (TCEP) was the most abundant of the thirteen OPEs, which reached up to 447.08 ng·L-1. Seasonal variation of OPEs showed that the concentrations of OPEs in summer ranged from 220-1557.96 ng·L-1, with the average concentration of 493.78 ng·L-1 being 1.7-2.6 times higher than of that in spring and autumn. An ecological risk assessment showed that tricresyl phosphate and 2-ethylhexyl diphenyl phosphate were associated with moderate or high risks to organisms (algae, crustaceans, and fish). At a high exposure concentration, the total non-carcinogenic risk of OPEs in source water ranged from 4.41×10-3-2.91×10-2, with the highest risk being associated with children aged 0-3 months. The total cancer risk value was 5.88×10-7-3.89×10-6, among which TCEP and Tris(1,3-dichloro-2-propyl) phosphate was associated with a potential risk for children. We conclude that the long-term exposure risk for children of OPEs in the source water of the Nanjing section of the Yangtze River deserve more attention.

Determination of 42 glucocorticoids in infant eczema products by auto-solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry

A method was developed for the determination of 42 glucocorticoids in infant eczema products by auto-solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (ASPE-UHPLC-MS/MS).The analytes were extracted by acetonitrile after dispersing in saturated sodium chloride solution.Macromolecules matrix were precipitated by adding potassium and zinc acetate, and then purified by HLB SPE column.The chromatographic separations were performed on a DIKMA EndeavorsilTM C18 column (100 mm×2.1 mm, 1.7 μm).Acetonitrile and 0.1%(v/v) formic acid aqueous solution were used as the mobile phases.Electrospray ionization (ESI) source was operated in the positive mode using multiple reaction monitoring (MRM) scanning mode.The results were quantified by external standard method.The correlation coefficients of linear calibration curves were greater than 0.998 in the corresponding mass concentration ranges.The average recoveries at three spiked levels ranged from 78.7% to 101.5%, and the relative standard deviations (RSDs) were 2.0%-8.8%(n=6).The LODs (S/N ≥ 3) and LOQs were 0.002-0.031 mg/kg and 0.0007-0.103 mg/kg, respectively.The method is simple, rapid, sensitive, and reliable, and can be used for the detection of glucocorticoids in infant eczema products.

Simultaneous determination of monepantel and its metabolite residues in cow and sheep milk by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

A method for the rapid and simultaneous determination of monepantel and its metabolite residues in cow and sheep milk has been developed using high performance liquid chromatography-tandem mass spectrometry. The samples were extracted with acetonitrile to precipitate the proteins and passed through a neutral alumina solid phase extraction (SPE) cartridge. The extracts were separated on an Inertsil C8-3 column (150 mm×4.6 mm, 5 μm) with a gradient elution program consisting of methanol and ammonium acetate. A triple stage quadrupole mass spectrometer equipped with an electrospray ionization source in negative ion mode was used to detect monepantel and its metabolite residues. The quantification of the analytes was performed by the external standard method. Good linear relationships between the peak areas and mass concentrations of the analytes were obtained in the range of 0.1-5.0 μg/L with correlation coefficients greater than 0.99 (n=6). The limits of quantification were 2.0 μg/kg. The recoveries of the analytes in cow and sheep milk at three spiked levels (2.0, 50, and 100 μg/kg) were in the range of 90.1%-103.3% with relative standard deviations between 2.0% and 6.2% (n=6). This method is fast, accurate, and highly sensitive, exhibits strong anti-interference capability with good recovery and repeatability, and can thus be used to simultaneously determine monepantel and its metabolite residues in cow and sheep milk.

Perfluoroalkyl acids in surface waters and tapwater in the Qiantang River watershed—Influences from paper, textile, and leather industries

Perfluoroalkyl acids (PFAAs) are widely used as multi-purpose surfactants or water/oil repellents. In order to understand the contamination level and compositional profiles of PFAAs in aqueous environment in textile, leather, and paper making industrial areas, surface waters and tap waters were collected along the watershed of the Qiantang River where China's largest textile, leather, and paper making industrial bases are located. For comparison, surface water and tapwater samples were also collected in Hangzhou and its adjacent areas. 17 PFAAs were analyzed by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. The results show that the total concentrations of PFAAs (ΣPFAAs) in the Qiantang River waters ranged from 106.1 to 322.9 ng/L, averaging 164.2 ng/L. The contamination levels have been found to be extremely high, comparable to the levels of the most serious PFAA contamination in surface waters of China. The PFAA composition profiles were characterized by the dominant PFOA (average 58.1% of the total PFAAs), and PFHxA (average 18.8%). The ΣPFAAs in tap water ranged from 9.5 to 174.8 ng/L, showing PFAA compositional pattern similar to the surface waters. Good correlations between PFAA composition profiles in tap waters and the surface waters were observed.

A cohort study on association between the first trimester phthalates exposure and fasting blood glucose level in the third trimester

Objective: To examine the association between the phthalate exposure in the first trimester and fasting blood glucose level or gestational diabetes mellitus (GDM) in the third trimester in pregnant women. Methods: A total of 3 474 pregnant women, receiving their prenatal examination in Ma' anshan Maternal and Child Health-Care Hospital of Anhui province, were selected from May 2013 to September 2014. Questionnaires were used to collect the information about their socio-demographic characteristics, clinical characteristics and GDM diagnostic results in the first, second and third trimesters. Urine samples and fasting venous blood samples were collected. Concentrations of 7 kinds of phthalate metabolites in urine samples were detected by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS), and multiple linear regression model was used for statistical analyses. Logistic regression analysis on the risk of the first trimester phthalate exposure for GDM in the third trimester was conducted. Results: The prevalence of GDM in this study was 12.8%, monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEHHP) exposure levels were positively correlated with the fasting blood glucose level in the third trimester (P<0.05), but mono-(2-ethylhexyl) phthalate (MEHP) and mono-(2-ethyl-5-hydroxylhexyl) phthalate (MEOHP) exposure levels were negatively correlated with the fasting blood glucose level in the third trimester (P<0.05). Stratified analysis showed a positive correlation between MEHHP exposure and the third trimester fasting blood glucose level in both normal group and GDM group. However, MMP, MEP, MBP, MBzP, MEHP and MEOHP exposure levels had influences on the third trimester fasting blood glucose level in normal group but not in GDM group. MMP and MBP exposure might increase the risk of GDM, but MEOHP exposure might reduce the risk of GDM. Conclusion: The phthalate exposure in the first trimester might be associated with the fasting blood glucose level in the third trimester, MMP, MEP, MBP, MBzP and MEHHP concentrations were positively associated with the third trimester blood glucose level, MEHP and MEOHP concentrations were negatively associated with the third trimester blood glucose level. Moreover, the effects of different kinds of phthalates might be different.

Quantification of three chlorinated dialkyl phosphates, diphenyl phosphate, 2,3,4,5-tetrabromobenzoic acid, and four other organophosphates in human urine by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry.

Polybrominated diphenyl ethers (PBDEs), produced as flame retardants worldwide, have been phased-out in many countries, and chlorinated and non-chlorinated organophosphates and non-PBDE brominated formulations (e.g., Firemaster 550 (FM550)) have entered the consumers' market. Recent studies show that components of organophosphate esters and FM550 are frequently detected in many products common to human environments. Therefore, urinary metabolites of these compounds can be used as human exposure biomarkers. We developed a method to quantifynine compounds in 0.4mL urine: diphenyl phosphate (DPhP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), bis-(1-chloro-2-propyl) phosphate, bis-2-chloroethyl phosphate, di-p-cresylphosphate, di-o-cresylphosphate (DoCP), di-n-butyl phosphate, dibenzylphosphate (DBzP), and 2,3,4,5-tetrabromobenzoic acid. The method relies on an enzymatic hydrolysis of urinary conjugates of the target analytes, automated off-line solid phase extraction, reversed phase high performance liquid chromatography separation, and isotope dilution-electrospray ionization tandem mass spectrometry detection. The method is high-throughput (96 samples/day) with detection limits ranging from 0.05 to 0.16ngmL-1. Spiked recoveries were 90-113%, and interday imprecision was 2-8%. We assessed the suitability of the method by analyzing urine samples collected from a convenience sample of adults (n = 76) and from a group of firefighters (n = 146). DPhP (median, 0.89; range, 0.26-5.6ngmL-1) and BDCPP (median, 0.69; range, 0.31-6.8ngmL-1) were detected in all of the non-occupationally exposed adult samples and all of the firefighter samples (DPhP [median, 2.9; range, 0.24-28ngmL-1], BDCPP [median, 3.4; range, 0.30-44ngmL-1]); DBzP and DoCP were not detected in any samples.

Quantification of urinary mono-hydroxylated metabolites of polycyclic aromatic hydrocarbons by on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry.

Human exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). Gas chromatography (GC) has been widely used to separate OH-PAHs before quantification by mass spectrometry in biomonitoring studies. However, because GC requires derivatization, it can be time consuming. We developed an on-line solid phase extraction coupled to isotope dilution-high performance liquid chromatography-tandem mass spectrometry (on-line-SPE-HPLC-MS/MS) method for the quantification in urine of 1-OH-naphthalene, 2-OH-naphthalene, 2-OH-fluorene, 3-OH-fluorene, 1-OH-phenanthrene, the sum of 2-OH and 3-OH-phenanthrene, 4-OH-phenanthrene, and 1-OH-pyrene. The method, which employed a 96-well plate platform and on-line SPE, showed good sensitivity (i.e., limits of detection ranged from 0.007 to 0.09ng/mL) and used only 100μL of urine. Accuracy, calculated from the recovery percentage at three spiking levels, varied from 94 to 113%, depending on the analyte. The inter- and intra-day precision, calculated from 20 repeated measurements of two quality control materials, varied from 5.2 to 16.7%. Adequate method performance was also confirmed by acceptable recovery (83-102%) of two NIST standard reference materials (3672 and 3673). This high-throughput on-line-SPE-HPLC-MS/MS method can be applied in large-scale epidemiological studies. Graphical abstract Example LC-MS chromatogram of urinary mono-hydroxylated PAH metabolites.

Effect of Constructed Wetland Configuration on the Removal of Nitrogen Pollutants and Antibiotics in Aquaculture Wastewater

Horizontal subsurface flow constructed wetland (HSSFCW) and integrated vertical flow constructed wetland (IVFCW) consisted of down-flow and up-flow were built to treat aquaculture wastewater under different conditions. The water treatment performance, especially the nitrogen pollutants and antibiotics removal efficiencies, were compared, and the effects of flow patterns and hydraulic retention time (HRT) on the efficiencies were studied. The results showed that IVFCW had a better removal efficiency on nitrogen pollutants, and the removal rates of TN and NH4+-N were 58% and 80% (HRT=3 d), respectively. Microbial community was further analyzed using BIOLOG microplate technique and 454-pyrosequencing. The internal structure of IVFCW was conducive to the flow and dissolved oxygen condition, which induced higher microbial activity and diversity. The richness in Nitrospira distribution was the main reason for the removal efficiency of ammonia nitrogen. HRT had a great influence on the removal of NO3--N and NO2--N, and maintaining 3-4 d could reach good efficiency for all kinds of nitrogen pollutants. Solid phase extraction-high performance liquid chromatography-tandem mass spectrometry analysis (SPE-HPLC-MS/MS) was used to test the removal efficiency of antibiotics, and the results showed that there was no remarkable difference between the two configurations. The removal efficiency of Enrofloxacin was higher than that of Sulfamethoxazole and Florfenicol. Extending HRT from 1 d to 3 d could significantly improve the removal rate of Sulfamethoxazole, reaching above 50%.

Distribution Characteristics and Health Risk Assessment of Thirteen Sulfonamides Antibiotics in a Drinking Water Source in East China

Trace levels of residual antibiotics in drinking water sources may threaten public health and becomes a serious issue in modern society. Occurrence and distribution of 13 sulfonamides antibiotics in a drinking water source in East China were investigated using solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. The results revealed that all 13 sulfonamides were detected with the total concentrations ranging from 10.5 ng·L-1 to 238.5 ng·L-1. Sulfamethoxazole (SMX) and sulfonamide (SAM) presented the 100% detected frequency, and the maximum concentrations reached 107.0 ng·L-1 and 43.1 ng·L-1, respectively. Sulfonamides contamination levels in the inlet were relatively higher than those in the outlet. The concentration of SMX was substantially unchanged in different positions of drinking water source. Seasonal variation of sulfonamide concentration showed that the concentrations were higher in winter and spring compared with those in summer and autumn. The range of total sulfonamides concentration detected in winter and spring was from 110.8 ng·L-1 to 117.9 ng·L-1, which was 3.6-3.8 times higher than those in summer and autumn. Human health risk characterization of residual sulfonamides in drinking water source was based on the assessment of risk quotients (RQs) for which different life stages were taken into account. The results showed that no sulfonamides had a RQs higher than 1. Trimethoprim (TMP) was the most risky antibiotic to the 0-3 months old infants with RQs reaching 0.001. Although the sulfonamides detected in the drinking water source do not pose any risk to the peoples' health, the implication of long-time exposure and comprehensive risk still deserve attention.

Determination of eight bisphenol diglycidyl ethers in water by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

A solid phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method was developed for the determination of eight bisphenol diglycidyl ethers, including bisphenol A diglycidyl ether (BADGE), bisphenol A (3-chloro-2-hydroxypropyl) glycidyl ether (BADGE x HCl), bisphenol A bis (3-chloro-2-hydroxypropyl) ether (BADGE x 2HCl), bisphenol A (2, 3-dihydroxypropyl) glycidyl ether (BADGE x H2O), bisphenol A bis(2,3-dihydroxypropyl) ether (BADGE x 2H2O), bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) ether (BADGE x HCl x H2O), bisphenol F diglycidyl ether (BFDGE) and bisphenol F bis (3-chloro-2-hydroxypropyl) ether (BFDGE 2HCl) in water. A total of ten samples were collected from the leaching of the coatings for drinking water supply system. Then, 200 mL exposure water was preconcentrated on C18 solid-phase extraction cartridge. The eight compounds were analyzed by liquid chromatography-tandem mass spectrometry method on a C18 column by the gradient elution with methanol, water and 5 mmol/L ammonium acetate as mobile phases in the multiple reaction monitoring (MRM) scan mode. The external matrix standard solutions were used for the quantitative determination and the calibration curves of the eight compounds showed good linearity in the range of 0.007-5.00 microg/L with the correlation coefficients more than 0.999 0. The limits of quantification (LOQs) of the method were 7-91 ng/L. The spiked recoveries ranged from 79.1% to 101% with the relative standard deviations of 4.0% - 12%. The method is sensitive and accurate, and is applicable to the determination of bisphenol diglycidyl ethers in water.

Determination of fungicide anilinopyrimidine residues in food by series solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method was established for the determination of fungicide anilinopyrimidine residues including pyrimethanil, mepanipyrim, and cyprodinil in foodstuffs with series solid phase extraction (SPE). The food sample was first extracted with ethyl acetate, and then purified by an ENVI-Carb cartridge and a Florisil SPE cartridge. The analytes were determined by HPLC-MS/MS and quantified by external standard method. The mass spectrometric detection was operated with electrospray in positive ionization mode and the fungicide anilinopyrimidines were identified in multiple reaction monitoring (MRM) mode. The linear range of the method was 1 - 20 microg/L, with the correlation coefficient (r2) over 0. 999 0. The transitions of the precursor ions to two selected product ions were involved, in which one group for quantification were m/z 200. 1/107. 1 for pyrimethanil, m/z 224. 0/106. 0 for mepanipyrim and m/z 226. 0/108. 1 for cyprodinil, and the other group for identification were m/z 200. 1/183. 1 for pyrimethanil, m/z 224. 0/131. 1 for mepanipyrim and m/z 226. 0/133. 1 for cyprodinil, respectively. No significant matrix effect was found for spiked samples after the purification. The recoveries of the fungicide anilinopyrimidines spiked in food samples were 73.2% -98.7% at the spiked levels of 0. 1, 0.5, 1.0 microg/kg. The relative standard deviations (RSDs) were less than 10%. The limits of detection (LODs) and limits of quantification (LOQs) were 0. 03 microg/kg and 0.1 microg/kg for the three fungicides, respectively. The results showed that the proposed method is sensitive and accurate for the determination of fungicide anilinopyrimidines in foodstuffs. The method should be applicable for routine analysis of pyrimethanil, mepanipyrim, cyprodinil residues in foodstuffs.

Determination of rhodamine B in spices by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

Rhodamine B (RB), as an unlawful colour, is forbidden to add into foods by Chinese government. A solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method for the determination of RB in spices has been developed. The sample was extracted by acetonitrile and then centrifugated, purified and enriched with a strong positive ion exchange SPE column (Bond Elut Plexa PCX SPE column) after adding 10 mL 1% trichloroacetic acid solution. The HPLC separation was performed on a Pursuit C18 column (100 mm x 2.0 mm, 3 microm) by gradient elution with 0.1% (v/v) formic acid solution and methanol as the mobile phase. The analyte was detected by electrospray ionization in positive ion mode-MS/MS in multiple reaction monitoring (MRM) mode. The good linearity (R2 > 0.99) was obtained over the range of 0.6-6 microg/L. The limit of quantification (LOQ) for RB was 1.2 microg/kg. The average recoveries were ranged from 80% to 121% at the spiked levels of 1.197, 2.992 and 5.985 microg/L, and the relative standard deviations (RSDs) were not more than 15%. The conditions of mobile phase elution gradients, extraction solvents, and SPE columns were optimized. This method is highly selective and has weak matrix effect for qualitative and quantitative analyses of RB in spices.

Determination of rhodamine B in spices by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

Determination of rhodamine B in spices by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry