Determination of anionic and nonionic surfactants, their degradation products, and endocrine-disrupting compounds in sewage sludge by liquid chromatography/mass spectrometry

A comprehensive analytical method based on reversed-phase liquid chromatography and mass spectrometry using both atmospheric pressure chemical ionization and electrospray ionization has been developed for the simultaneous determination of anionic and nonionic surfactants, their polar degradation products, and endocrine-disrupting compounds (EDCs) in sewage sludge. Extraction of target compounds, with recovery rates from 86% to nearly 100% for polyethoxylates and from 84 to 94% for polar degradation products, was achieved applying ultrasonic solvent extraction with a mixture of methanol/ dichloromethane (7:3, v/v). Cleanup of sample extracts was performed on octadecyl solid-phase extraction cartridges. Determination of less polar compounds: alcohol ethoxylates (AEOs), nonylphenol ethoxylates (NPEOs), coconut diethanol amides, poly(ethylene glycol)s, and phthalate esters was accomplished by reversed-phase LC-APCI-MS in positive ionization mode, while more polar compounds: nonylphenolcarboxylates, nonylphenol (NP), octylphenol, and bisphenol Awere analyzed by ion-pair LC-ESI-MS under negative ionization conditions. This protocol was successfully applied to the trace determination of anionic and nonionic surfactants, polar degradation products, and EDCs in sewage sludge collected from different sewage treatment plants. The analysis revealed the presence of NP at high concentration levels ranging from 25 to 600 mg/kg. Polyethoxylates (AEOs and NPEOs) were also found in all samples at parts-per-million levels (10-190 mg/kg AEOs and 2-135 mg/kg NPEOs, respectively).     

纸质食品包装材料中 26 种有机残留物的检测

目的建立纸质食品包装材料中7种指示性多氯联苯、7种增塑剂、7种氯酚类化合物、2种二苯酮类化合物,以及4-辛基酚、2-异丙基硫杂蒽酮和硬脂酸甲酯同时检测的分析方法。方法采用超声提取,气相色谱-串联四极杆质谱多反应监测模式分析。结果 26种有机残留物在0.02~2.0 mg/kg范围内线性关系良好(r20.997),加标浓度在0.1 mg/kg时的平均回收率为88.9%~105.5%,相对标准偏差低于12.2%;方法的检出限为0.000 90~0.0035 mg/kg,定量限为0.0031~0.012 mg/kg。应用该方法对实际样品进行了检测,发现绝大多数样品中均检测出邻苯二甲酸二苯酯类增塑剂(检出含量为0.006~7.02 mg/kg),部分样品还检测出硬脂酸甲酯(检出含量为0.069~0.43 mg/kg)。结论该方法简单、快速、准确、灵敏,可用于纸质食品包装材料及类似基质中多种有机残留物的同时检测。     

食品中违禁色素橙黄II和酸性间胺黄的HPLC测定研究

本文建立了用液相色谱法同时测定食品中橙黄II、酸性间胺黄含量的测定方法,样品经丙酮溶剂提取后、固相萃取小柱净化、用ZorbaxExtendC18柱分离,二极管阵列检测器检测、外标法定量;橙黄II、酸性间胺黄的定量下限为0.2mg/kg,食品中添加回收率分别为(84-90)%和(78-82)%,相对标准偏差RSD(n=6)均小于6.5%。     

食品接触材料中邻苯二甲酸酯的LTQ-Orbitrap组合式高分辨质谱快速筛查和确证

建立了食品接触材料中邻苯二甲酸酯快速筛查确证的高效液相色谱-高分辨质谱法(HPLC-LTQ-Orbi-trap/MS)。实验中采用加速溶剂萃取(ASE)法为样品前处理手段,优化了萃取溶剂、萃取温度、静态萃取时间等实验参数,提高了食品接触材料中邻苯二甲酸酯的提取效率。采用高分辨质谱有效地去除了基体干扰,通过静电场轨道阱全扫描得到的精确相对分子质量进行了化合物的定量,用离子阱的二级质谱图对未知化合物进行了进一步确证。结果表明:邻苯二甲酸酯的检测限为1 ng/mL;该方法的加标回收率为89.8%～101.3%,相对标准偏差均小于8.0%;所建立的方法简单,灵敏度高,适用于食品接触材料中邻苯二甲酸酯类增塑剂的筛查和检测。     

Simultaneous extraction and fractionation of polycyclic aromatic hydrocarbons and their oxygenated derivatives in soil using selective pressurized liquid extraction

In this study, a selective pressurized liquid extraction (PLE) method which can extract polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (oxy-PAHs) from contaminated soil and simultaneously separate them into two fractions was developed. The method uses extraction cells packed with a chromatographic adsorbent and extraction solvents of increasing polarity. Several experiments were conducted on both spiked and authentic contaminated soil samples. Different types of adsorbents, combinations of extraction solvents, and extraction temperatures were tested in order to find a method that could fulfill the purpose of the study. The final method was based on extraction cells packed with 2% deactivated silica gel. The PAHs were extracted with cyclohexane/dichloromethane (9:1) at 120 degrees C, after which the oxy-PAHs where extracted with cyclohexane/dichloromethane (1:3) at 150 degrees C. The PAHs and oxy-PAHs were efficiently separated into two fractions, and only trace amounts of some compounds were found in the inappropriate fraction. The recoveries of the PAHs were mostly above 70% and of the oxy-PAHs, above 90%. The linearity of the method was good, and the calibration curves for most compounds had a regression coefficient better than 0.99 and an intercept close to the origin of coordinates. When the selective PLE method was applied to seven authentic soil samples, the results were found to be in good agreement with those of a reference method based on Soxhlet extraction and silica gel cleanup and also in good agreement with the certified reference values available for one of the soils. The selective PLE method is faster and consumes less solvent than a traditional method based on separate extraction and fractionation steps. The selective PLE method is, therefore, suitable for the concurrent analysis of PAHs and oxy-PAHs during large-scale soil contamination studies. This will provide more information about the soil contamination and the levels of toxicity than an ordinary PAH analysis.     

Photocatalytic degradation of carbofuran using semiconductor oxides

The photocatalytic degradation of carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) was investigated in an aqueous solution using Degussa P-25 TiO2 and ZnO as photocatalysts. The progress of degradation was monitored using TOC analyzer, HPLC, GC-MS and UV-vis spectrophotometer. The effects of various experimental parameters such as initial concentration of carbofuran, pH of the solution, catalyst loading and light intensity were systematically studied in order to achieve maximum degradation efficiency. The complete mineralization of carbofuran was confirmed by TOC analyzer. The degradation with ZnO showed less efficiency than TiO2. The formation of NO(3)(-) was identified and quantified using HPLC. In addition, four different intermediates formed during the degradation process were also identified and characterized by GC-MS. The mineralization rate was compared with lamps of wavelength 254 and 365 nm under similar conditions. The rate with 254 nm was observed to be very close to that of 365 nm.     

气相色谱-质谱法测定食品包装中的柠檬酸脂

目的采用气相色谱-质谱法测定食品包装材料中柠檬酸三乙酯、柠檬酸三丁酯、乙酰柠檬酸三丁酯、柠檬酸三辛酯的增塑剂。方法采用正己烷超声萃取处理待测样品,全扫描定性目标物,选择离子扫描定量。结果 4种增塑剂的线性相关系数r0.997,回收率为92.7%~102.3%,相对标准偏差为3.2%~7.3%。结论该方法操作简单,结果准确,灵敏度高,稳定性好,适用于食品包装材料中4种柠檬酸酯增塑剂的同时测定。     

高效液相色谱定量分析煤衍生重质产品

针对煤衍生重质产品的组分分析,以高效液相色谱（HPLC）研究了其定量问题。首先,建立高分辨的色谱分离体系,使组分得以好的分离和定性。对各分离组分定量测定采用了外标法和外标-定量因子法。实验表明准确定量的技术关键在于：溶解样品溶剂的合理选择;配制样品溶液浓度的正确控制;配制样品溶液的进一步处理技术。     

Simultaneous determination of halogenated derivatives of alkylphenol ethoxylates and their metabolites in sludges, river sediments, and surface, drinking, and wastewaters by liquid chromatography-mass spectrometry

A quantitative solid-phase extraction-liquid chromatography/mass spectrometry (SPE-LC/MS) method is described for the simultaneous analysis of halogenated byproducts of alkylphenolic compounds and their degradation products formed during chlorine disinfection in the presence of bromide ions. Compounds analyzed include brominated and chlorinated nonylphenol ethoxylates (XN-PEOs); octylphenol ethoxylates (XOPEOs); nonylphenols (XNP); nonylphenoxycarboxylates (XNPECs) and their precursors nonionic surfactants, alkylphenol ethoxylates (APEOs); and their metabolites formed during sewage treatment, alkylphenoxycarboxylates (APECs) and alkylphenols (APs). Target compounds were concentrated from water samples using a C18 SPE procedure. Extracts were analyzed using reversed phase LC/MS. The performances of both atmospheric pressure chemical ionization (APCI) and electrospray (ESI) interfaces were compared. ESI offered better sensitivity and specificity for a higher range of oligomers. Detection limits (LODs) for water samples were from 20 to 100 ng/L; and for sediment samples, from 2 to 10 microg/kg. Slightly higher LODs were obtained for sludge samples (5-25 microg/kg). Halogenated byproducts were found in sludge from Barcelona drinking water treatment plant in concentrations of 220 microg/kg for BrNP, 430 microg/kg for BrNPEOs (nEO = 1 - 2), and 1600 microg/kg for BrNPEOs (nEO = 3 - 15). The concentration of ClNPEOs was estimated to be in the order of 660 microg/kg (assuming the same response as BrNPEOs). Halogenated OPEOs were also identified, and their concentration was approximately 50 times lower than the concentration of NPEOs analogues. To our knowledge, this is the first method described that allows simultaneous determination of alkyphenol ethoxylates and halogenated derivatives, including degradation products.     

Degradation of carbofuran by using ozone, UV radiation and advanced oxidation processes.

The degradation of carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate), a frequently used carbamate derivative pesticide that is considered a priority pollutant, is carried out in batch reactors by means of single oxidants: ozone, UV radiation and Fenton's reagent; and by the advanced oxidation processes (AOPs) constituted by combinations of ozone plus UV radiation, UV radiation plus H(2)O(2), and UV radiation plus Fenton's reagent (photo-Fenton system). For all these reactions, the apparent pseudo-first-order rate constants are evaluated in order to compare the efficiency of each process. In addition and by means of a competition kinetic model, the rate constants for the reaction of carbofuran with ozone and with hydroxyl radicals are also determined. The improvement in the decomposition levels of carbofuran reached by the combined processes in relation to the single oxidants, due to the generation of the very reactive hydroxyl radicals, is also established in every process. For the oxidant concentrations applied, the most effective process in removing carbofuran was the photo-Fenton system.     

Oxidative degradation and detoxification of aqueous carbofuran by membrane anodic Fenton treatment

Anodic Fenton treatment (AFT), a new Fenton technology for the treatment of pesticide wastewater, has been reported previously. The substitution of an ion exchange membrane for the salt-bridge, an improvement to the practicality of the AFT without sacrificing treatment efficiency, has also been reported. The oxidative degradation by membrane AFT of carbofuran, a heavily used and toxic carbamate insecticide, was investigated in this study. The results show that the degradation kinetics of carbofuran with different initial concentrations obeys the AFT model, and the treatment efficiency increases with increasing initial concentration. Raising the treatment temperature can result in enhanced degradation of carbofuran in solution. The pseudo-activation energy of carbofuran by membrane AFT was estimated to be 7.66 kJ mol(-1). The results also show that AFT treatment can effectively remove COD and dramatically improve the biodegradability of carbofuran in solution. GC/MS analysis found four degradation products, revealing that the carbamate branch and 3-C in the furan ring are the first and second attack targets of hydroxyl radicals. As shown by the toxicity assay, the fatal toxicity of carbofuran to earthworms can be totally removed. The degradation of carbofuran by AFT is also a detoxification process.     

Shape-selective extraction of PCBs and dioxins from fish and fish oil using in-cell carbon fractionation pressurized liquid extraction

This paper describes a new shape-selective, pressurized liquid extraction (PLE) procedure for extracting polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and PCBs from food and feed samples with an integrated carbon fractionation step. Initially this was done using specially designed inserts for 34-mL cells, but subsequently, large solid cells (66 mL) were machined to increase the capacity and robustness of the system. Depending on the carbon load and extraction solvent strength, the non-ortho PCBs were recovered either with the bulk of the PCBs or with the PCDD/Fs. The former is preferable if PCDD/Fs are the targets. In most cases, however, data are required for all indicator PCBs, WHO-PCBs, and PCDD/Fs. Therefore, further efforts focused on developing, optimizing, and validating a cost- and time-efficient PLE procedure that can extract these targets, separate non-ortho PCBs and PCDD/Fs from the bulk of the PCBs, allow gravimetric fat determinations, and requires a minimum of postextraction cleanup. The performance of the resulting procedure was assessed in experiments with a fish tissue reference material. The trueness of the WHO-PCB-TEQ, PCDD/F-TEQ, and total-TEQ data were -8, -5, and -7%, respectively, and the corresponding CVs were 1.5, 0.5, and 1.3%; within the limits set by the European community for gas chromatography-high-resolution mass spectrometry methods for food and feed control.     

A validated stability indicating LC method for Nateglinide

A simple, isocratic, rapid and accurate reverse phase high-performance liquid chromatography (RP-HPLC) method was developed for the quantitative determination of Nateglinide. The developed method is also applicable for determination of related substance in bulk drugs. The chromatographic separation was achieved on a Hypersil C18 (250 × 4.6 mm 5 μm) column using aqueous mixture of 0.025 M potassium hydrogen phosphate and 0.1% triethyl amine, v/v (pH 3.0 with dilute phosphoric acid)—methanol (25:75, v/v) as a mobile phase. Solution concentrations were measured on a weight basis to avoid the use of an internal standard. The chromatographic resolutions between Nateglinide and its potential impurities A and B were found to be greater than four. Forced degradation studies were performed for Nateglinide using acid (0.5 N hydrochloric acid), base (0.5 N sodium hydroxide), oxidation (3% hydrogen peroxide) heat (60°C) and UV light (254 nm). The limit of detection and limit of quantification of Nateglinide, impurities A and B were found to be 0.05 and 0.15 μg /mL, respectively for 20 μL injection volume. The percentage recovery of Nateglinide was ranged from 98.4 to 100.9. The percentage recovery of impurities in Nateglinide sample was ranged from 96.8 to 103.5. The developed RP-HPLC method was validated with respect to linearity, accuracy, precision, robustness, and forced degradation studies prove the stability indicating power of the method.     

固相萃取-气相色谱-质谱法测定鸡蛋中160种农药残留

建立了串联组合柱固相萃取-气相色谱-质谱法检测鸡蛋中160种农药多残留的分析方法。鸡蛋样品用乙腈均质和超声波提取,提取液采用C18和PSA串联组合柱净化,气相色谱-质谱仪(GC-MS)分析。GC-MS采用SIM模式,外标法定量。在优化过的条件下进行测试,本法检出限(S/N≥3)为0.01~0.05 mg/kg,在加标水平为0.05 mg/kg时,方法回收率为63.2%~126%,相对标准偏差为2.3%~13%。     

高效液相色谱法同时测定饲料中的雌二醇和甲基睾丸酮

本文建立了一种用高效液相色谱法同时检测饲料中雌二醇和甲基睾丸酮的新方法。饲料样品经乙酸乙酯提取,采用液液萃取法净化浓缩,经液相色谱分离后用二极管阵列器检测。在0.5~10.0 mg/L浓度范围内,两种激素呈良好的线性关系,相关系数均大于0.9997。在添加水平0.1~2.0 mg/kg范围内,雌二醇的平均回收率为71%～86%,甲基睾丸酮的平均回收率为76%～91%,相对标准偏差均小于9.6%。雌二醇、甲基睾丸酮最低检出限(S/N=3)均为0.03 mg/kg,定量限(S/N=10)为0.1 mg/kg。该方法灵敏度高,测定结果准确,适用于饲料中雌二醇和甲基睾丸酮的同时检测。     

Speciation analysis of gadolinium-based MRI contrast agents in blood plasma by hydrophilic interaction chromatography/electrospray mass spectrometry

The first analytical method for simultaneous speciation analysis of five of the most important gadolinium-based magnetic resonance imaging (MRI) contrast agents in blood plasma samples was developed. Gd-DTPA (Magnevist), Gd-BT-DO3A (Gadovist), Gd-DOTA (Dotarem), Gd-DTPA-BMA (Omniscan), and Gd-BOPTA (Multihance) were separated by hydrophilic interaction liquid chromatography (HILIC) and detected with electrospray mass spectrometry (ESI-MS). Spiking experiments of blank plasma with Magnevist and Gadovist were performed to determine the analytical figures of merit and the recovery rates. The limits of detection ranged from 1 x 10 (-7) to 1 x 10 (-6) mol/L depending on the ionization properties of the individual compounds, and limits of quantification ranged from 5 x 10 (-7) to 5 x 10 (-6) mol/L. The linear concentration range comprised 2 orders of magnitude. With application of this method, blood plasma samples of 10 healthy volunteers, with Magnevist or Gadovist medication, were analyzed for Gd-DTPA and Gd-BT-DO3A, respectively. The obtained results were successfully validated with inductively coupled plasma-optical emission spectroscopy (ICP-OES).     

Quantification of human uridine-diphosphate glucuronosyl transferase 1A isoforms in liver, intestine, and kidney using nanobore liquid chromatography-tandem mass spectrometry

Uridine-disphosphate glucuronosyl transferase (UGT) enzymes catalyze the formation of glucuronide conjugates of phase II metabolism. Methods for absolute quantification of UGT1A1 and UGT1A6 were previously established utilizing stable isotope peptide internal standards with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The current method expands upon this by quantifying eight UGT1A isoforms by nanobore high-performance liquid chromatography (HPLC) coupled with a linear ion trap time-of-flight mass spectrometer platform. Recombinant enzyme digests of each of the isoforms were used to determine assay linearity and detection limits. Enzyme expression level in human liver, kidney, and intestinal microsomal protein was determined by extrapolation from spiked stable isotope standards. Intraday and interday variability was <25% for each of the enzyme isoforms. Enzyme expression varied from 3 to 96 pmol/mg protein in liver and intestinal microsomal protein digests. Expression levels of UGT1A7, 1A8, and 1A10 were below detection limits (<1 pmol/mg protein) in human liver microsome (HLMs). In kidney microsomes the expression of UGT1A3 was below detection limits, but levels of UGT1A4, 1A7, 1A9, and 1A10 protein were higher relative to that of liver, suggesting that renal glucuronidation could be a significant factor in renal elimination of glucuronide conjugates. This novel method allows quantification of all nine UGT1A isoforms, many previously not amenable to measurement with traditional methods such as immunologically based assays. Quantitative measurement of proteins involved in drug disposition, such as the UGTs, significantly improves the ability to evaluate and interpret in vitro and in vivo studies in drug development.     

Validation of Liquid Chromatographic Method of Assay for Acetaminophen,Butalbital and Caffeine in Solid Dosage Forms

Abstract

The validation of a liquid chromatographic procedure for the determination of acetaminophen, butalbital and caffeine in solid dosage forms is described. The dosage content of tablets or capsules is diluted and chromatographed on a Radialpak Cyanopropylsilane Cartridge with a mobile phase of water-acetonitrile-1M dibutylamine phosphate (90+9+1, V/V) with detection at 215 nm. The calibration curve is linear with correlation coefficients of 0.999 for each component. Recoveries of spiked excipient blend averaged 99.5% for acetaminophen, 102.5% for butalbital and 101.0% for caffeine. The method met USP requirements for system suitability with proper resolution between two adjacent peaks. The relative standard deviation (RSD) of peak response of each component (obtained by chromatographing six replicates of standard solution) is less than 2.0% and the tailing factor of each component is not greater than 1.5. The method can be used for composite, content uniformity and dissolution assay of acetaminophen, butalbital and caffeine in tablet and capsule formulations.     

Validation of Liquid Chromatographic Method of Assay for Acetaminophen, Butalbital and Caffeine in Solid Dosage Forms

The validation of a liquid chromatographic procedure for the determination of acetaminophen, butalbital and caffeine in solid dosage forms is described. The dosage content of tablets or capsules is diluted and chromatographed on a Radialpak Cyanopropylsilane Cartridge with a mobile phase of water-acetonitrile-1M dibutylamine phosphate (90+9+1, V/V) with detection at 215 nm. The calibration curve is linear with correlation coefficients of 0.999 for each component. Recoveries of spiked excipient blend averaged 99.5% for acetaminophen, 102.5% for butalbital and 101.0% for caffeine. The method met USP requirements for system suitability with proper resolution between two adjacent peaks. The relative standard deviation (RSD) of peak response of each component (obtained by chromatographing six replicates of standard solution) is less than 2.0% and the tailing factor of each component is not greater than 1.5. The method can be used for composite, content uniformity and dissolution assay of acetaminophen, butalbital and caffeine in tablet and capsule formulations.     

High-performance liquid chromatography assay for indorenate in pharmaceutical powders

A high-performance liquid chromatographic (HPLC) method for quantification of indorenate admixed of pharmaceutical excipients (Pharmatose DCL 21, Povidone USP and Helmcel 200) is described. Indorenate was extracted from the mixtures using a mobile phase composed of acetonitrile and a sodium acetate buffer solution 0.1 M (63:37) and separated from other dissolved components by ion supression-HPLC. The method was standardized using a C-18 column (250 mm × 4.8 mm, i.d., 5 μm). The photometric detector was fixed at 228 or 272 nm depending on the admixed excipients. Validation parameters included linearity, precision, accuracy, reproducibility, and specificity. The method was specific, selective, and capable to distinguish indorenate from their degradation products and the antihypertensive pelanserine.