Determination of nickel in blood and serum samples of oropharyngeal cancer patients consumed smokeless tobacco products by cloud point extraction coupled with flame atomic absorption spectrometry

Oropharyngeal cancer is a significant public health issue in the world. The incidence of oropharyngeal cancer has been increased among people who have habit of chewing smokeless tobacco (SLT) in Pakistan. The aim of present study was to evaluate the concentration of nickel (Ni) in biological samples (whole blood, serum) of oral (n?=?95) and pharyngeal (n?=?84) male cancer patients. For comparison purposes, the biological samples of healthy age-matched referents (n?=?150), who consumed and did not consumed SLT products, were also analyzed for Ni levels. As the Ni level is very low in biological samples, a preconcentration procedure has been developed, prior to analysis of analyte by flame atomic absorption spectrometry (FAAS). The Ni in acid-digested biological samples was complexed with ammonium pyrrolidinedithio carbamate (APDC), and a resulted complex was extracted in a surfactant Triton X-114. Acidic ethanol was added to the surfactant-rich phase prior to its analysis by FAAS. The chemical variables, such as pH, amounts of reagents (APDC, Triton X-114), temperature, incubation time, and sample volume were optimized. The resulted data indicated that concentration of Ni was higher in blood and serum samples of cancer patients as compared to that of referents who have or have not consumed different SLT products (p?=?0.012–0.001). It was also observed that healthy referents who consumed SLT products have two to threefold higher levels of Ni in both biological samples as compared to those who were not chewing SLT products (p? Figure

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流动注射-火焰原子吸收法快速测定水样化学需氧量

采用流动注射-火焰原子吸收法(FI-FAAS)测定水样化学需氧量.以KMnO4作氧化剂、葡萄糖作基准物质,在95 ℃反应,生成的Mn(Ⅱ)在线分离吸附于阳离子交换树脂微型柱上,用3 mol/L HCl洗脱后,送至火焰原子吸收检测器检测.在反应盘管长500 cm、反应时间30 s的条件下,测定化学需氧量的线性范围为8.00～200.00 mg/L,检出限为2.30 mg/L;采样频率为24次/h,Cl-质量浓度至100 mg/L无干扰,Mg2 质量浓度至1 000 mg/L无干扰;对50.00 mg/L的化学需氧量标样重复测定7次,相对标准偏差为3.37%.用该法测定河水、池塘水和轻度污染工业废水的化学需氧量,获得了与重铬酸盐法(标准方法)基本一致的测定结果.     

高压消解-石墨炉原子吸收法测定大气飘尘中的微量钯

试验建立了一种测定大气飘尘中微量钯的新方法。使用高压消解采样滤膜 ,丁二酮肟 -氯仿萃取体系 ,用涂钼热解石墨管石墨炉原子吸收分光光度法对大气中的钯进行测定。方法的检出限为 6 .4× 10 - 1 0 g,对于 30 ng/ m L钯的测定 ,相对标准偏差3.8% ,可用于测定大气飘尘中的微量钯。对郑州市多处空气样进行分析 ,结果满意。     

4种重金属离子对间接火焰原子吸收光谱法测定铝的干扰

空气-乙炔间接火焰原子吸收法是我国目前运用较多且易于推广的铝检测方法,研究了Mg2+、Ca2+、Zn2+和Ni2+4种离子对此法测定0.40 mg/L Al3+ 的干扰情况。得出如下结论:(1)在±5% 误差范围内,15.10 mg/L Mg2+、105.00 mg/L Ca2+、0.23 mg/L Zn2+、0.88 mg/L Ni2+对0.40 mg/L Al3+ 无干扰。(2)本方法虽然操作复杂,但成本较低、灵敏度高,检测的浓度范围宽、稳定性好,加标回收率为96%~99%,检出限为0.04 mg/L,适宜测定范围为0.05~100.00 mg/L,适用于饮用水、河水及地下水中Al3+ 的测定。     

Method validation for control determination of mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry

A method for the determination of total mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) has been validated following international foodstuff protocols in order to fulfill the Brazilian National Residue Control Plan. The experimental parameters have been previously studied and optimized according to specific legislation on validation and inorganic contaminants in foodstuff. Linearity, sensitivity, specificity, detection and quantification limits, precision (repeatability and within-laboratory reproducibility), robustness as well as accuracy of the method have been evaluated. Linearity of response was satisfactory for the two range concentrations available on the TDA AAS equipment, between approximately 25.0 and 200.0 μg kg^?1 (square regression) and 250.0 and 2000.0 μg kg^?1 (linear regression) of mercury. The residues for both ranges were homoscedastic and independent, with normal distribution. Correlation coefficients obtained for these ranges were higher than 0.995. Limits of quantification (LOQ) and of detection of the method (LDM), based on signal standard deviation (SD) for a low-in-mercury sample, were 3.0 and 1.0 μg kg^?1, respectively. Repeatability of the method was better than 4%. Within-laboratory reproducibility achieved a relative SD better than 6%. Robustness of the current method was evaluated and pointed sample mass as a significant factor. Accuracy (assessed as the analyte recovery) was calculated on basis of the repeatability, and ranged from 89% to 99%. The obtained results showed the suitability of the present method for direct mercury measurement in fresh fish and shrimp samples and the importance of monitoring the analysis conditions for food control purposes. Additionally, the competence of this method was recognized by accreditation under the standard ISO/IEC 17025.     

Literature survey of on-line spectroscopic methods for lead determination in environmental solid samples

A review is presented where are shown the advantages involved in the use of flow injection (FI) analysis for the determination of lead in environmental solid samples by spectroscopic detectors. The FI methods proposed for the determination of lead in these samples are described and compared according to the detection technique used. Analytical data of interest and interferences are discussed for each technique.     

The determination of toxaphene in environmental samples by negative ion electron capture high resolution mass spectrometry

A method is described for the analysis of toxaphene in environmental samples by high resolution gas chromatography high resolution mass spectrometry in selected ion electron capture negative ion mode. Toxaphene is detected by monitoring [M-Cl]- fragments ions of chlorobornanes (Cl6-Cl10) and chlorobornenes (Cl6-Cl7) using formal ion ratio criteria. The method shows high sensitivity and excellent specificity for the detection of chlorobornanes with negligible interference from of a wide range of common environmental organochlorines including chlordanes, PCBs and PCB-oxygen adducts. The analytical scheme is applicable to sediment and biological tissue samples and typically provide sample detection limits of less than 0.2 ng/g technical toxaphene for a 10 g sample.     

Routine, automated determination of inorganic and total mercury in multimedia using cold vapour atomic absorption spectrometry

A routine, automated analytical method for simultaneous determination of total and inorganic mercury by cold vapour atomic absorption spectrometry in multimedia is described. Excellent accuracy and precision results were obtained with human hair certified reference materials namely, BCR-397 and IAEA-086. The reproducibility relative standard deviation for total mercury was 4% and 22%, respectively. The limit of detection for total and inorganic mercury was 0.2 μg/g hair. The described method has been successfully applied in determination of total and inorganic mercury as well as organic mercury in human hair, urine and fish tissue samples.     

Comparison of supercritical fluid extraction and Soxhlet extraction for the determination of PCBs in seaweed samples

The efficiency of supercritical fluid extraction for the determination of 12 polychlorinated biphenyls from algae samples is compared to Soxhlet extraction. Analytical detection limits for the individual congeners ranged from 0.62 microgl(-1) to 19 microgl(-1). Recovery was tested for both methods using standard addition procedure. At maximum spike level of concentration, the mean recoveries were not significantly different (P>0.05) of all PCBs studied, with the exception of PCBs 28, 52, 77 and 169. Method precision for Soxhlet extraction (< or =3.9%) was slightly better than for SFE (< or =9.2%). Although both methods yield comparable results, SFE offers the advantage of detecting all PCBs studied at lower concentrations, reducing extraction time, and reducing the amount of solvents needed. The optimized methods were applied to the analysis of three real seaweed samples, except for PCB101 the concentrations of all PCBs were low or below the detection limits. The levels of PCB101 found in sample 1 were 6.6+/-0.54 ng g(-1) d.w., in sample 2 the levels were 8.2+/-0.86 ng g(-1) d.w. and in sample 3 they were 7.7+/-0.08 ng g(-1) d.w.     

Validation of a hydride generation atomic absorption spectrometry methodology for determination of mercury in fish designed for application in the Brazilian national residue control plan

In the present study, a method for the determination of mercury (Hg) in fish was validated according to ISO/IEC 17025, INMETRO (Brazil), and more recent European recommendations (Commission Decision 2007/333/EC and 2002/657/EC) for implementation in the Brazilian Residue Control Plan (NRCP) in routine applications. The parameters evaluated in the validation were investigated in detail. The results obtained for limit of detection and quantification were respectively, 2.36 and 7.88 μg kg^?1 of Hg. While the recovery varies between 90–96%. The coefficient of variation was of 4.06–8.94% for the repeatability. Furthermore, a comparison using an external proficiency testing scheme was realized. The results of method validated for the determination of the mercury in fish by Hydride generation atomic absorption spectrometry were considered suitable for implementation in routine analysis.     

Trace level determination of selected organophosphorus pesticides and their degradation products in environmental air samples by liquid chromatography-positive ion electrospray tandem mass spectrometry

This paper describes a new analytical method for determination of organophosphorus pesticides (OPs) along with their degradation products involving liquid chromatography (LC) positive ion electrospray (ESI+) tandem mass spectrometry (MS-MS) with selective reaction monitoring (SRM). Chromatography was performed on a Gemini C6-Phenyl (150 mmx2.0 mm, 3 microm) with a gradient elution using water-methanol with 0.1% formic acid, 2 mM ammonium acetate mobile phase at a flow rate of 0.2 mL min(-1). The LC separation and MS/MS operating conditions were optimized with a total analysis time less than 40 minutes. Method detection limits of 0.1-5 microg L(-1) for selected organophosphorus pesticides (OP), OP oxon degradation products, and other degradation products: 3,5,6-trichloro-2-pyridinol (TCP); 2-isopropyl-6-methyl-4-pyrimidol (IMP); and diethyl phosphate (DEP). Some OPs such as fenchlorphos are less sensitive (MDL 30 microg L(-1)). Calibration curves were linear with coefficients of correlation better than 0.995. A three-point identification approach was adopted with area from first selective reaction monitoring (SRM) transition used for quantitative analysis, while a second SRM transition along with the ratio of areas obtained from the first to second transition are used for confirmation with sample tolerance established by the relative standard deviation of the ratio obtained from standards. This new method permitted the first known detection of OP oxon degradation products including chlorpyrifos oxon at Bratt's Lake, SK and diazinon oxon and malathion oxon at Abbotsford, BC in atmospheric samples. Atmospheric detection limits typically ranged from 0.2-10 pg m(-3).     

Electrochemical study of the fungicide acibenzolar-s-methyl and its voltammetric determination in environmental samples

The electrochemical behavior of new generation fungicide acibenzolar-s-methyl (S-methyl 1,2,3-benzothiadiazole-7-carbothioate, ASM) on the hanging mercury drop electrode (HMDE) was investigated using square wave adsorptive stripping voltammetry. This method of determination is based on the irreversible reduction of ASM at the HMDE. The well-defined ASM peak was observed at ?0.4 V (vs. Ag/AgCl) in BR buffer at pH 2.2. The reduction peak current was proportional to concentration of ASM from 1.0 × 10^?8 to 6.0 × 10^?8 mol L^?1 with detection and quantification limit 3.0 × 10^?9 and 1.0 × 10^?8 mol L^?1, respectively. The applicability of the developed method for analysis of spiked samples of tap water, river water, and soil is illustrated. The effect of adsorption on the mercury electrode was studied in detail using the AC impedance method. Possible interferences with other common pesticides and heavy metal ions were examined. Clarification of the electrode mechanism was made using cyclic voltammetry (CV) technique.     

On the use of metal-organic frameworks for the extraction of organic compounds from environmental samples

Environmental Science and Pollution Research - The determination of trace metals and organic contaminants in environmental samples, such as water, air, soil, and sediment, is until today a...     

New Evidence for the presence of arsenocholine in shrimps (Pandalus borealis) by use of pyrolysis gas chromatography — atomic absorption spectrometry/mass spectrometry

An analytical method for the structure elucidation of quarternary organoarsenic compounds in trace amounts in fish and crustaceans has been developed in this laboratory. The two major organoarsenicals found in shrimps have been separated by ion-exchange chromatography and their stucture has been studied by the use of pyrolysis gas chromatography. Their degradation in the pyrolyzer unit has been studied by the use of atomic absorption spectrophotometer or mass spectrometer as detectors. A comparison of the analytical data of these substances and data from synthetic reference substances show complete agreement. The structures of reference compounds have been confirmed by use of nuclear magnetic resonance spectrometry and fast atom bombardment (FAB) mass spectrometry. It is demonstrated that both of the organoarsenic compounds in shrimps have a trimethylarsonio moiety e.g. the compounds have a quarternary structure. Furthermore, the more basic organoarsenic compound has a mass spectrometric fragmentation pattern similar to synthetic arsenocholine and acetylarsenocholine. Treatment of arsenobetaine with hot base produces trimethylarsineoxide in a high yield (96%). Arsenocholine, however, remains unchanged during this treatment. Treatment with sodium benzenethiolate does not result in chemical demethylation, which shows that this method together with gas chromatography-mass spectrometry is not feasible for confirmation of its structure.     

流动注射免疫分析及其在环境中农药残留分析研究综述

介绍了流动注射免疫分析、顺序流动注射免疫分析方法及其流动注射脂质体、荧光、化学发光、电化学等检测技术分析环境中的农药残留     

15N Metabolic test for the determination of phytotoxic effects of chemicals and contaminated environmental samples

A stable isotope¹⁵N-nitrogen test (ESIMA = Ecotoxicological Stable Isotope Metabolic Assay) was developed to assess biological effects and the potential toxicological hazard of chemicals and contaminated environmental samples on plant metabolism. The assay measures the effect of toxicants on the incorporation of a¹⁵N labelled tracer into the total nitrogen fraction (both the nonprotein and protein fraction) of plants. Segments ofPisum arvense epicotyls are used as test substrates because of their high metabolic activity. The plant material is incubated under standardised conditions for two hours; subsequently¹⁵N incorporation is analysed by determining the¹⁵N abundance (¹⁵N atom-%) in the epicotyl segments. The effects of toxicants are evaluated by comparing the¹⁵N incorporation rates of control tissue and epicotyl segments exposed to individual chemicals or complex environmental samples. The specificity and sensitivity of effects as indicated by ESIMA were compared with effects as measured by two established ecotoxicological bioassays, the pollen tube growth test using pollen ofNicotiana sylvestris and the bacterial luminescence inhibition test using pollen ofPhotobacterium phosphoreum. The results of the study clearly indicate the suitability of ESIMA for assessing toxic impacts on plant nitrogen metabolism. Prof. Dr. habil. Hans Faust dedicated to his 70^th birthday.     

流动注射荧光猝灭法测定环境水样中痕量磷

在硫酸溶液中，P(Ⅴ)与钼酸盐、钒酸盐生成磷钼钒杂多酸，使罗丹明6G荧光猝灭，据此建立了测定痕量磷的流动注射荧光猝灭方法。方法的测定范围为2～90μg／L,进样频率为35样/h。采用本法测定环境水样中痕量磷，结果令人满意。     

Preparation of antibodies and development of an enzyme immunoassay for determination of atrazine in environmental samples

An indirect competitive enzyme-linked immunosorbent assay (ELISA) has been developed and optimized for atrazine determination in soil at different depths (0–10, 10–20, and 20–30 cm) before and after 48 h of application, corn shoot and cow milk samples collected from Dina farm, Egypt. This assay was based on a specific polyclonal antibodies (PAb) raised by immunizing New Zealand rabbits with an immunogen prepared by coupling 3-{4-(ethylamino)-6-(isopropylamino)-1,3,5-triazine-2-yl} thiopropanoic acid to bovine serum albumin (BSA) via N-hydroxysuccinimide (NHS) active ester method. The sensitivity (estimated as IC₅₀value) was 17.5 μg mL^?1 with a detection limit of 0.1 ng mL^?1. The maximum atrazine concentration was found in soil especially in the deepest layer (325 and 890 μg kg^?1 before and after application, respectively). Atrazine concentration in corn shoot was 333.28, μg kg^?1 dry plant, while there was no detectable amount in milk. All samples screened by ELISA were validated by gas chromatography mass spectrometer procedure (GC/MS). Good correlation was achieved between the two methods (r = 0.997 for soil and 0.9814 for plant). This study demonstrates the utility and convenience of the simple, practical and cost–effective ELISA method in the laboratory for analysis of environmental samples. The method is ideal for the rapid screening of large numbers of samples in laboratories where access to GC/MS facilities, is limited or lacking.