Determination of lead in the urine of exposed and unexposed adults by extraction and flow-injection/atomic absorption spectrometry

Lead is extracted from urine with ammonium pyrrolidien dithiocrbamate into methyl isobutyl ketone, and 20 μl of the extract is injected into a water carrier stream in a flow-injection/atomic absorption system. The procedure is simple, quick, accurate and reproducible. Recoveries are 96–105%. The mean urine lead contents of 20 unexposed and 20 printing-press lead exposed workers was found to be 39.0 ± 8.3 and 71.7 ± 26.3 μg Pb l^?1, respectively.     

Simultaneous Determination of Tolbutamide and its Metabolites in Biological Fluids

Abstract

A_pH dependent solvent extraction system has been developed to separate tolbutamide and its two known metabolites formed in man. The separated components are quantitatively converted into N-butyl-2, 4-dinitroaniline and can be measured either colorimetrically, when the concentrations are greater than 10 μg/ml of biological fluid, or via gas chromatography with electron capture detection, when the concentrations are less than 10 μg/ml. Plasma concentrations and excretion rates of drug and metabolites following intravenous administration of 1.0 g tolbutamide to man is reported.     

The direct determination of cadmium in urine by electrochemical atomic absorption spectrometry with the L'vov platform

A simple, direct procedure for the measurement of cadmium in urine is described. Graphite-furnace atomic absorption spectrometry is used in conjunction with selective atomisation at 800°C from a L'vov platform. Urine samples are diluted with an equal volume of deionised water and 20-μl aliquots are injected. Calibration is done by standard additions. The sensitivity is 0.016 μg Cd l^?1 for 1% absorption for a 20-μl sample. Within-run precision is 4.9% at 0.84 μg l^?1. The detection limit is 0.06 μg l^?1, which allows normal unexposed levels of cadmium in urine to be determined. The method is applicable to the determination of urinary cadmium levels of both occupationally non-exposed and exposed populations.     

Determination of N-Nitroso Compounds in the Environment of a Metal Factory Using Metalworking Fluids

Abstract

By use of GLC-ECD and HPLC-TEA techniques for N-nitroso compounds, N-nitroso-diethanolamine (NDELA) has been found in concentrations of 1.4–6.0 μg/m³ and 1.3–5.0μg/m³ respectively in all four air samples collected in the environment of a metalworking plant during metallurgical operations. NDELA was quantitated in air samples by GLC-ECD after converting it to its trifluoroacetyl derivative by reaction with the appropriate anhydride. NDELA was analyzed without derivatization in air samples using HPLC-TEA method. N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were also identified and later determined in two out of four air samples in concentrations of 0.08μg/m³ (for NDMA in both samples) and 0.14–0.16μg/m³ (for NDEA) using GLC-TEA procedure. The described method did not cause artifactual formation of N-nitrosomethyl-N-butylamine (NMBA) when methyl-N-butylamine was used as an internal marker of nitrosation during collection of NDELA in impinger traps.     

Organic Compounds in High Alpine Snow

Abstract

Snow samples were taken in June 1995 at the Sonnblick Observatory located at the top of Mt. Sonn-blick (3106 m a.s.l.) in the main ridge of the Austrian Alps, as part of the project “Organic Aerosol Scavenging”. The main interest focused on the determination of aliphatic compounds and phenols. First the method for the extraction of the organic compounds was developed using standard samples prepared in the lab. The preconcentration of the samples was performed by liquid-liquid extraction with hexane and hexane/diethylether respectively. To characterize the analytical procedure, the efficiency of the extraction procedure, the reproducibility of the overall method and the detection limits were determined. Values for the recovery of the extraction method range from 57% (fatty acids) to 95% (aliphatic alcohols). Reproducibility was found to be between 3-5%, except for the fatty acids which gave a value of 16%. Detection limits were calculated for the various substances and are between 5μg/l (phenols) and 30μg/l (fatty acids). The analysis of the eight snow samples were performed using a GC-MS-FID system. The following compounds were identified as major compounds in the snow samples: 1-dodecanol, 1-tetradecanol, 1-hexadecanol, 1-octadecanol, 2-isobutyl-4-methoxy-phenol, diisobutylphenol and dibutylphthalate. The aliphatic alcohols are of biogenic origin and are present in a concentration range from 30 to 115 μg/l melted snow. The phenols show concentrations between 5 and 30 μg/l and the phthalates range up to 40 μg/l.     

Identification and quantitative analysis of physalin D and its metabolites in rat urine and feces by liquid chromatography with triple quadrupole time‐of‐flight mass spectrometry

Physalin D is known to show extensive bioactivities. However, no excretion study has elucidated the excretion of physalin D and its metabolites. This study investigates the excretion of physalin D and its metabolites in rats. Metabolites in rat urine and feces were separated and identified by liquid chromatography with triple quadrupole time‐of‐flight mass spectrometry. Furthermore, a validated high‐performance liquid chromatography with tandem mass spectrometry method was developed to quantify physalin D, physalin D glucuronide, and physalin D sulfate in rat feces and urine after the intragastric administration of physalin D. The analyte showed good linearity over a wide concentration range (r  > 0.995), and the lower limit of quantification was 0.0532 μg/mL and 0.226 μg/g for urine and feces, respectively. Nine metabolites, including five phase I and four phase II metabolites, were identified and clarified after dosing in vivo. Only 4.0% of the gavaged dose, including physalin D and its phase II metabolites, was excreted in urine, whereas 10.8% was found in feces in the unchanged form. The results indicate that the extensive and rapid metabolism may be the main factors leading to the short half‐life of physalin D. These results can provide a basis for further studies on the structural modification and pharmacology of physalin D.     

Detection of catecholamine metabolites in urine based on ultra-high-performance liquid chromatography–tandem mass spectrometry

The excretion of neurotransmitter metabolites in normal individuals is of great significance for health monitoring. A rapid quantitative method was developed with ultra-performance liquid chromatography–tandem mass spectrometry. The method was further applied to determine catecholamine metabolites vanilymandelic acid (VMA), methoxy hydroxyphenyl glycol (MHPG), dihydroxy-phenyl acetic acid (DOPAC), and homovanillic acid (HVA) in the urine. The urine was collected from six healthy volunteers (20–22 years old) for 10 consecutive days. It was precolumn derivatized with dansyl chloride. Subsequently, the sample was analyzed using triple quadrupole mass spectrometry with an electrospray ion in positive and multireaction monitoring modes. The method was sensitive and repeatable with the recoveries 92.7–104.30%, limits of detection (LODs) 0.01–0.05 μg/mL, and coefficients no less than 0.9938. The excretion content of four target compounds in random urine samples was 0.20 ± 0.086 μg/mL (MHPG), 1.27 ± 1.24 μg/mL (VMA), 3.29 ± 1.36 μg/mL (HVA), and 1.13 ± 1.07 μg/mL (DOPAC). In the urine, the content of VMA, the metabolite of norepinephrine and adrenaline, was more than MHPG, and the content of HVA, the metabolite of dopamine, was more than DOPAC. This paper detected the levels of catecholamine metabolites and summarized the characteristics of excretion using random urine samples, which could provide valuable information for clinical practice.     

Use of Derivative Spectrophotometry for the in Vitro determination of Phenylbutazone and Oxyphenbutazone in Human Plasma

Abstract

Fourth derivative-difference (ΔD₄.) spectrophoto metry is presented for the simultaneous assay of phenylbutazone and oxyphenbutazone as metabolites of bumadizone either in laboratory made mixtures or in human plasma. Phenylbutazone and oxyphenbutazone are determined through the measurement of ΔD₄ signals at 293 and 282 nm, respectively. The linear relationship of these values versus concentration of both compoundsin the range 1–5 μg/ml for phenylbutazone and 3–8 μg/ml for oxyphenbutazone permits their determination with high accuracy and good reproducibility. The relative standard deviation is less than 1.35% The proposed method could be used for monitoring bumadizone metabolites.     

The determination of vanadium in sea and natural waters,biological materials and silicate sediments and rocks

Vanadium was concentrated from sea and natural waters by coprecipitation with iron (III) hydroxide, and separated from iron and other elements by ion exchange, using hydrogen peroxide as a very selective eluting agent. The element was determined photometrically with diaminobenzidine. The ion-exchange process was also used to separate vanadium from other elements in the analysis of silicate rocks and marine plants. Coefficients of variation of 2.8%, 1.3% and 2.5% were found for the determination of the element in sea water, marine sediments and marine plants at levels of 1.8 μg/l, 57 μg/g and 2.2 μg/g, respectively. The U.S. Geological Survey standard granite GI was found to contain 17.2±0.9μg V/g.     

An HPLC Method for the Determination of Theophylline and Its Metabolites in Serum and Urine

Abstract

A urine and a serum assay have been developed to quantitate theophylline and its major metabolites:1,3-dimethyluric acid, 3-methylxanthine and 1-methyluric acid. Reverse phase chromatography follows a serum acetone extraction procedure and a urine anion exchange clean-up procedure. Lower limits of sensitivity are 0.04 μg/ml for serum metabolites and 1 μg/ml for urine metabolites. Both assays are free of interference from endogenous substances. These assays have been tested successfully in pharmacokinetic and metabolic studies of theophylline.     

Trichocitrin,a new fusicoccane diterpene from the marine brown alga-endophytic fungus Trichoderma citrinoviride cf-27

One new diterpene, trichocitrin (1), and four known secondary metabolites, nafuredin (2), 5-hydroxy-2,3-dimethyl-7-methoxychromone (3), 24-methylenecycloartanol (4) and citrostadienol (5), were isolated from the culture of marine brown alga-endophytic Trichoderma citrinoviride cf-27. Trichocitrin (1) represents the first Trichoderma-derived and furan-bearing fusicoccane diterpene, and its structure and relative configuration were identified by analysis of 1D/2D NMR and mass spectroscopic data. Compounds 1 and 2 exhibited 8.0- and 9.5-mm inhibition zones, respectively, against Escherichia coli at 20 μg/disc and 54.1 and 36.7% growth inhibition, respectively, of Prorocentrum donghaiense at 80 μg/mL.     

Metabolism profile of scutellarin in urine following oral administration to rats by ultra performance liquid chromatography coupled to time-of-flight mass spectrometry

Scutellarin, a flavone glucuronide of 5,6,4′-trihydroxyflavone-7-O-glucoronide, is the main active component of the traditional Chinese botanic drug Erigeron breviscapus (Vant.) Hand.-Mazz. In this study, a method based on ultra performance liquid chromatography coupled with a time-of-flight mass spectrometer (UPLC/TOF MS) was established and validated to profile the metabolites of scutellarin in Sprague-Dawley rat urine following oral administration of single dose of scutellarin at 80.8 mg/kg. The column utilized was an Acquity BEH C18 (150 mm × 2.1 mm, 1.7 μm). The mobile phase was 0.2% formic acid and acetonitrile with gradient condition. Two standard curves of scutellarin were obtained for the concentration range of 1.065-10.65 μg/mL and 10.65-63.92 μg/mL, respectively. By automating the data processing of the software Masslynx developed by Waters Ltd., 17 metabolites of scutellarin were found and determined in rat urine, with the corresponding reactions in vivo such as isomerism, reduction, methylation, glucuronide conjugation, hydroxylation, hydroxylation and methylation, etc., most of which were discovered for the first time. For most metabolites, the time (T_p) of peak excretion was 8-12 h. Calculated as scutellarin, the cumulative urine excretion rate of the metabolites was 1.93%.     

Determination of tenuazonic acid in human urine by means of a stable isotope dilution assay

The content of tenuazonic acid in human urine was determined by a stable isotope dilution assay (SIDA) that was recently developed for the analysis of food commodities and extensively re-validated for urine matrix in this study. Linearity of the response curve was proven between molar ratios n(labeled standard)/n(analyte) of 0.02–100. The limits of detection and determination were 0.2 and 0.6 μg/L, respectively. The mean recovery of the stable isotope dilution assay was 102?±?3 % in the range between 1.0 and 100 μg/L. Interassay precision was 6.7 % (relative standard deviation of three triplicate analyses of a human urine sample during 3 weeks). The method was applied to two studies dealing with urinary excretion of tenuazonic acid: In the first study, tenuazonic acid was quantified in the 24-h urine of six volunteers from Germany (three female, three male) in a concentration range of 1.3–17.3 μg/L or 2.3–10.3 ng/mg^?1 creatinine, respectively. In the second study, two volunteers (one female, one male) ingested 30 μg tenuazonic acid by consumption of naturally contaminated whole meal sorghum infant cereals and tomato juice, respectively. The urinary excretion of the ingested tenuazonic acid was 54–81 % after 6 h, depending on matrix and volunteer. After 24 h, 87–93 % of the ingested amount of tenuazonic acid was excreted, but the fate of the remaining about 10 % is open. Thus, it is not possible to exclude potential health hazards for the consumer, completely.

Organic Compounds In Cloud And Rain Water

Abstract

Cloud and rain water samples have been collected in spring 1991 in the Vosges mountains (France) and analyzed for aldehydes, phenols and polycyclic aromatic hydrocarbons (PAHs). Both passive and active cloud collectors have been employed. A mean concentration of formaldehyde of 197 μg/l (6.6 μM) has been found in cloud water while on the average only 100 μg/l (3.3 μM) were observed in rain water. The average phenol concentration was 3.5 μg/l (37 nM), but only 1.6 μg/l (17 nM) in rain water. Finally, the mean concentration of PAHs (only determined in cloud water) amounts to 0.37 μg/l. The PAH profile is similar to that observed for rain water sampled in Hannover (Germany).     

The Boron and Lithium Content of South African Coals and Coal Ashes

Abstract

Boron and lithium were determined in over a hundred coals and power station ashes by inductively coupled plasma atomic emission spectroscopy. The levels of boron in coals and fly ashes range from 15 to 83 μg.g^?1 and from 23 to 600 μg.g^?1, respectively, while lithium occurred at levels of between 45 and 81μg.g^?1 in coals and 77 and 359μg.g^?1 in fly ashes. Both elements were found to vary considerably between different coals and ashes produced. In most cases the boron concentration was found to increase systematically between the first and last precipitators where smaller particle size fractions are collected. The availability of boron from the leaching of fly ashes by water was investigated. Leachabilities were found to vary for ashes produced at different power stations.     

An Enzyme Immunoassay for the Determination of Methabenzthiazuron

Abstract

A sensitive enzyme immunoassay is described for the determination of the urea herbicide methabenzthiazuron. The assay is carried out with polyclonal antibodies, which were raised in rabbits by immunization with a methabenzthiazuron-BSA conjugate containing five methabenzthiazuron residues per molecule. The ELISA was optimized on microtiter plates with a peroxidase-methabenzthiazuron tracer. The middle of the test (50% B/B₀) was found at 1.0 μg/l. The lower detection limit of methabenzthiazuron is c. 0.05 μg/l. Samples can be measured up to 10 μg/l methabenzthiazuron (upper detection limit). The assay does not require concentration or clean-up steps for drinking or ground water samples. Validation experiments showed a good accuracy and precision. Work with monoclonal antibodies is in progress.     

The impact of nitrogen fertilizers on degradation and leaching of chlorotoluron in soil

Abstract

This study presents the developed and applied methods for the determination of carbendazim in environmental samples originating from several field studies.

For water samples sample pretreatment consisted of a solid phase extraction (SPE) on cartridges packed with 200 mg SDB-1. In case of solid samples the performance of microwave assisted solvent extraction (MASE) and classical ultrasonic extraction with acetone-ethyl acetate were studied. The latter technique was selected because of the reduced time of manual operations. Instrumental analysis of extracts of water samples was performed on-line with coupled column reversed phase liquid chromatography (LC/LC) and UV detection (280 nm) allowing to assay carbendazim to a level of at least 0.1 μg/l. Improved column life time was obtained by performing the favorable LC separation of carbendazim at high pH on newly developed 5 μm Extend-pH bidentate C18 material.

The combination of a short column packed with 5 μm Inertsil ODS-5 and a mobile phase at low pH material was most adequate as the regards the robust and fast processing of extracts of solid samples and allowed in most cases the screening of carbendazim in soils and sediments to a level of 10μg/kg.

The developed procedures yield overall recoveries for carbendazim of 101, 80 and 71 % in water (levels, 0.1—1.2 μg/l: n=12), soil (levels, 10 and 100 μg/kg; n=22) and sediments (levels, 10 and 100 μg/kg; n=11), respectively, with a repeatability and reproducibility below 7 % for all method/matrix combinations. Soil samples with aged residues (level, 100 μg/kg; n=10) provided an overall recovery of 71% and no significant decrease of carbendazim was observed during nine weeks of storage in the refrigerator.     

HPLC Separation of Theophylline,Paraxanthine, Theobromine,Caffeine and Other Caffeine Metabolites in Biological Fluids

Abstract

An HPLC method is described for rapid analysis of caffeine and seven of its metabolites in plasma, urine, milk and saliva in a single operation using a 5 μ C₁₈ reverse phase column. The metabolites are extracted with chloroform - iso-propanol (85:15) from 100 μL samples added to NH₄HCO₃. No interference from normal blood, urine, milk or saliva constituents was observed. The method is accurate and precise and separates 1,7-dimethylxanthine (paraxanthine) from 1,3-dimethylxanthine (theophylline). Sensitivity for most metabolites is in the range of 0.1 to 0.3 μg/mL and the detectability is at the nanogram level.     

Antimicrobial compounds from root,stem bark and seeds of Melia volkensii

Three compounds, toosendanin (1), kulactone (2) and scopoletin (3), were isolated from either the root bark and/or the stem bark of Melia volkensii. Their structures were determined on the basis of spectroscopic data generated and by comparison with data from the literature. 1 and 2, isolated for the first time from M. volkensii, exhibited significant (p < 0.05) activity against Escherichia coli with minimum inhibitory concentration of 12.5 μg/mL, close to that of neomycin (6.25 μg/mL). The compounds also exhibited high activity against Aspergillus niger (MIC 6.25 μg/mL compared to 2.5 μg/mL for clotrimazole). Dichloromethane and methanol seed, hexane stem bark and methanol root bark extracts exhibited activities towards Escherichia coli, Staphylococcus aureus, Aspergillus niger and Plasmodium falciparum, respectively. Antimicrobial activity of the plant towards A. niger, P. falciparum and S. aureus is reported for the first time in the current work.     

Linear Scan Stripping Voltammetry at Glassy-Carbon Based Thin Mercury Film Electrodes for Determination of Trace Aluminium in Dialysis Fluids.

Abstract

Linear scan cathodic stripping voltammetry at glassy-carbon based thin mercury film electrodes is a simple and inexpensive alternative for determining trace Al(III) in dialysis fluids.

The efficiency of a variety of ligands (SVRS, Cupferron and Blue Black Eriochrome R) was evaluated comparing their voltamperometric response by application of a linear scan mode, after preconcentration into the mercury film electrode as Al(III) complexes.

The best results were obtained when Cupferron was used as ligand, since its stripping current compares favourably in terms of sensitivity and resolution. The sharply defined cathodic peak at -1.3 V, corresponding to the reduction of the interfacial accumulated complex, could be used for quantitation. The response is linear up to 50 μg/l; correlation coefficient, 0.995. The relative standard deviation (at 20 μg/l level) is 3.5%, a detection limit of 0.5μg/l was estimated from the signal to noise characteristics of the response for 5 μg/l, which compares favourably among the reported electroanalytical methods for aluminium.

We calibrated the method under conditions of use estimating the trace aluminium exposure in patients undergoing dialytic treatment.