GC FPD method for the simultaneous speciation of butyltin and phenyltin compounds in waters

A method is described for the simultaneous determination of nanogram amounts of mono-, di- and tri-butyltin compounds in water. The procedure is based on the conversion of tin compounds to volatile species by Grignard pentylation and analysis using GC with flame photometric detection (GC FPD). The ionic compounds are extracted from diluted acidified (HBr) aqueous solutions by using a pentane-tropolone solution. The extracted organotin compounds are pentylated by a Grignard reagent and purified on a Fluorisil column before analysis by GC FPD. The detection limits are 20 ng dm^?3 for butyltin compounds and 50 ng dm^?3 for phenyltin compounds. Recoveries from spiking experiments in tap-water and natural seawater matrices, in which no organotin compounds were detected, were greater than 90% for most of the alkyltin compounds.     

Determination of phenyltin compounds by reversed-phase liquid chromatography

An analytical procedure for the determination of phenyltin compounds in environmental sample waters was studied. Chromatography of mono-, di- tri-phenyltin (MPT, DPT and TPT) was performed on a reversed-phase C₁₈ column with the mobile phase comprising methanol/10⁻² M H₃PO₄ (80:20 v/v) at pH 3 and UV detection at 214 nm. To enhance the sensitivity of the detection system, the post-column reaction between morin or 3-hydroxyflavone and phenyltin compounds was formed before fluorescence detection. Several parameters affecting the fluorescence intensity were studied systematically, including the optimum condition for the post-column reagent that was also compatible with the eluent. The parameters concerned in this study were the pH, the percentage of Triton X-100, the ratio of fluorigenic reagent to phenyltin compounds and the amount of methanol in the eluent. Detection limits before the preconcentration process were in the region of 1.5 ppb for TPT and 150–250 ppb for MPT and DPT, respectively. Utilizing solid-phase extraction on a C₁₈ cartridge for sample clean-up as well as preconcentration successfully reduced the detection limit of TPT to the level of ng dm⁻³ and can be applied to seawater analysis. Recovery in the range 95.0–98.0% was obtained by developing the optimum elution profile in the preconcentration step. © 1998 John Wiley & Sons, Ltd.     

Tributyltin analysis in seawater by GC FPD after direct aqueous-phase ethylation using sodium tetrathylborate

Using sodium tetraethylborate as an alkylation reagent, one-step ethylation and extraction of organotin compounds in seawater was performed directly in the aqueous phase to obtain optimal rection conditions. No further purification or concentration of the extract was required before GC FPD analysis. The detection limit for monobutyl-dibutyl-and tributyl-tin was approximately 0.4 ng dm^?3, which is adequate for any currently know toxicity effect. The linearity range (0–200 ng dm^?3) was solely dependent on the detector response curve. Compared with the Grignard reaction after extraction in an organic solvent, this new ethylation procedure reduces the number of analytical steps, thus saving time and improving reliability.     

Determination of Butyltins in Sea Water by Gas Chromatography with Flame Photometric Detection

Use of a gas chromatograph with a flame-photometric detector (GC-FPD) is described to determine butyltin compounds in sea water. The butyltins in an acidified water sample (pH 3.0) are first complexed with tropolone, followed by solid-phase extraction (SPE) with a tropolone-treated C₁₈ cartridge. HCI at a small concentration is then added to the concentrated SPE eluate before GC analysis. This procedure is simple and off-column derivatization of analytes is not required. The organotins, viz. mono-, di- and tributyltin, are separated as their respective chlorides on a capillary column (HP-1) and are detected with a flame-photometric detector and an interference filter at 610 nm. Recoveries of the three butyltin species are quantitative (> 90%). Based on a sea water sample 200-mL, the detection limits for mono-, di- and tributyltin are 6,4 and 3 ng tin L^?1, respectively. This method is applied to analysis of trace butyltins in various samples of sea water.     

Analytical Method Development for the Simultaneous Determination of Five Human Pharmaceuticals in Water and Wastewater Samples by Gas Chromatography-Mass Spectrometry

Summary Effective analytical methods for the simultaneous determination of five pharmaceuticals from various therapeutic classes in a variety of aqueous samples have been developed and method performance data are presented. The method involves the simultaneous extraction of the selected pharmaceuticals from the aqueous phase by solid phase extraction using a hyper cross linked, polystyrene-divinylbenzene polymer based sorbent. Analytes were eluted with methanol, derivatised with N-methyl-N-trimethylsilyltrifloroacetamide and analysed by gas chromatography – electron ionisation mass spectrometry (GC-EI-MS). Recoveries of 50 to 98% were established for waters spiked with the studied compounds at the low ng L^–1 level with the highest detection sensitivities being achieved in the selected ion monitoring (SIM) mode and the quantification limit of the procedure for sample sizes of 1000 ml was approximately 5 ng L^–1 for all matrices except sewage which was only tested to 20 ng L^–1. Analysis of domestic sewage from a large treatment works demonstrate the presence of all five compounds in both influents and effluents.     

Evaluation of the atmospheric pressure photoionization source for the determination of benzidines and chloroanilines in water and industrial effluents by high performance liquid chromatography-tandem mass spectrometry

A solid phase extraction-high performance liquid chromatography-tandem mass spectrometry based analytical method suitable for simultaneous analysis of benzidine, 3,3′-dichlorobenzidine, mono-, di-, and tri-chloroanilines has been developed.Normal phase separation by liquid chromatography was performed using a cyano propyl methyl silica column, and atmospheric pressure photoionization was employed as interface with mass spectrometer.The developed method was evaluated in terms of limit of detection, accuracy, and precision. The quantification limit for all the compounds ranged between 7 and 112 ng L⁻¹, while recovery for all the compounds was higher than 94%. The method was tested by analyzing different industrial wastes, showing residual contamination by most of the analytes.     

Speciation of organotin in sediments by multicapillary gas chromatography with atomic emission detection after microwave-assisted leaching and solvent extraction-derivatization

Microwave-assisted leaching of organotin compounds from sediment samples followed by the simultaneous extraction-derivatization of the extracted species was revisited with the goal to compare the existing procedures, improve their recoveries and extend them to phenyltin compounds. The stability of butyl- and phenyltin compounds under microwave field, real recoveries of the whole analytical procedure, effect of the extraction solvent, and the necessity for an internal standard were evaluated using two candidate reference sediments. The combination of the optimized sample preparation procedure with multicapillary chromatography resulted in a rapid (2 min leaching + 5 min extraction-derivatization + 3 min chromatographic separation) and efficient analytical procedure for speciation analysis of organotin compounds in sediment samples. The detection limit achieved with a microwave-induced plasma atomic emission detector was 2 ng g^–1. Received: 27 July 1998 / Revised: 31 August 1998 / Accepted: 4 September 1998     

Simultaneous multielement‐specific detection of a novel glutathione–arsenic–selenium ion [(GS)2AsSe]− by ICP AES after micellar size‐ exclusion chromatography

In order to confirm the solution structure of [(GS)₂AsSe]⁻ (GS = glutathione), we have investigated the retention behaviour of a [(GS)₂AsSe]⁻/oxidized glutathione (GSSG) mixture on a Sephadex G‐25 (SF) column with Tris buffers (0.1 mol dm⁻³, pH 8.0) containing ­various surfactants at concentrations above the critical micellar concentration (CMC): hexadecyltrimethlammonium bromide (HDTAB; 30, 40 and 50 mmol dm⁻³); dodecyltrimethylammonium bromide (DDTAB; 50 mmol dm⁻³); and sodium lauryl sulfate (SLS; 50 mmol dm⁻³). ­An inductively coupled plasma atomic emission spectrometer (ICP AES) provided simultaneous on‐line detection of arsenic, selenium and ­sulfur in the column effluent. The chromatographic retention behaviour was used to investigate the association of both compounds with the positively charged micelles (HDTAB and DDTAB mobile phases). The relative strength of association with the micelles provided insight into the effective negative charge on [(GS)₂AsSe]⁻ and GSSG. The chromatograms obtained with 50 mmol dm⁻³ HDTAB indicated that two glutathione molecules are associated with the elution of an arsenic–selenium compound. Combined, these chromatographic data strongly support the spectroscopically derived solution structure of [(GS)₂AsSe]⁻. Copyright ­© 2000 John Wiley & Sons, Ltd.     

Speciation of organotin compounds in water by gas chromatography/atomic absorption spectrometry

Summary A reproducible and interference-free method is presented for simultaneous determination of individual tri-, di- and monoalkyltin species present in aqueous systems. The ionic methyltin and butyltin compounds are extracted from water into pentane as diethyldithiocarbamate complexes at pH 5. The organic phase is then evaporated to dryness under reduced pressure, after which derivatization withn-pentyl (Pe) Grignard reagent is carried out in a microvolume ofn-octane to form pentylated alkyltin compounds R _n SnPe_(4-n) (R = Methyl, Me or Butyl, Bu). The quantitation is subsequently performed by gas chromatography with quartz furnace atomic absorption spectrometric detection (GC-AAS). Absolute detection limits range between 0.16 ng and 0.40 ng Sn for the various organotin species, allowing speciation in natural water down to the 4-10 ng 1^–1 level.

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Speziation von organischen Zinnverbindungen in Wasser durch GC/AAS

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Dedicated to Prof. Dr. G. Tölg on the occasion of his 60th birthday     

The Distribution of Arsenic Compounds in the Ocean: Biological Activity in the Surface Zone and Removal Processes in the Deep Zone

The vertical profies of inorganic arsenic [As(III)+As(V)], monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) were investigated at four sampling stations in the Pacific Ocean and a sampling station in the southern Tasman Sea. In addition, the concentrations of those compounds in surface waters of the Pacific Ocean and Tasman Sea have been determined. The vertical profiles of inorganic arsenic showed the low concentrations in both the surface and deep/bottom zones. The depleted concentrations in the surface zone varied from 1000 to 1700 ng dm⁻³ and that in the deep/bottom zone varied from 1300 to 2050 ng dm⁻³. The maximum concentrations that varied from 1500 to 2450 ng dm⁻³ were usually observed at a depth of about 2000 m. Both MMAA and DMAA were observed throughout the water column at sampling stations in the north-western and equatorial regions of the Pacific Ocean. At the sampling station in the central northern Pacific gyre, DMAA was the only methylated arsenic compound observed throughout the water column. On the contrary, at the sampling station in the southern Tasman Sea, the only detected methylated arsenic compound throughout the water column was MMAA. Their vertical profiles showed maximum concentrations in the surface water which abruptly dropped with depth from 0 to 200 m. The concentration in the surface water was close to 10 ng dm⁻³ for MMAA and varied from 27 to 185 ng dm⁻³ for DMAA. At depths greater than 100 m, MMAA and DMAA were at comparable concentrations which varied from 0.7 to 14 ng dm⁻³. The low inorganic arsenic concentration in the surface zone was due to biological activity. This activity resulted in the uptake of As(V) and subsequent reduction and methylation to MMAA and DMAA. DMAA was the main predominant arsenic compound resulting from biological activity in surface waters. The low inorganic arsenic concentrations in the deep and bottom zones were likely to be caused by the adsorption of dissolved inorganic arsenic onto sinking particulates rich in iron and manganese oxides.     

Development and optimization of a method for the analysis of phenols and chlorophenols from aqueous samples by gas chromatography-mass spectrometry, after solid-phase extraction and trimethylsilylation

A 3-step analytical procedure was developed and optimized for the simultaneous determination of 6 phenols (phenol, o-, m-, p-cresol, catechol and resorcinol) and 19 chlorophenols (all mono-, di-, tri-, and tetrachlorophenol isomers and pentachlorophenol) from environmental water samples. The analytical scheme consists of (1) solid-phase extraction (SPE) carried out on hypercrosslinked styrene-divinylbenzene (Isolute ENV+) cartridge; (2) derivatization with trimethylsilyl-N,N-dimethylcarbamate (TMSDMC); (3) analysis of the derivatives with capillary gas chromatography-mass spectrometry, in the selective ion monitoring mode. Ethyl acetate, ethyl acetate/acetic acid (5 v/v%) mixture, dichloromethane and acetonitrile were compared as to their ability to elute the phenols and chlorophenols from the ENV + sorbent in the smallest solvent volume possible. The optimized extraction step uses a minimal amount of organic solvent (4 mL ethyl acetate). Derivatization of the phenols and chlorophenols with TMSDMC was studied with respect to conversion, reagent excess, medium, temperature and the stability of the trimethylsilyl derivatives. If the reagent is applied in sufficient excess, the reaction takes place instantaneously at room temperature, and the derivatives remain stable for 24 h, making the procedure simple, fast and convenient. The overall method gave detection limits of 0.05-100 ng/L for all compounds except resorcinol which could not be retained on the SPE cartridge. The complete optimized analytical scheme was applied to ground water and river water samples collected in Hungary.     

Speciation of butyltin compounds by ion chromatography coupled to electrothermal atomic absorption spectrometry

A new method for the determination of butyltin species by ion-exchange chromatography linked with graphite-furnace electrothermal atomic absorption spectrometry (ETAAS) is presented. The separation is achieved on a strong cation-exchange column with a 0.18 mol dm^?3 solution of diammonium citrate at pH 6.5 with a step change to pH 4.0 in 60:40 methanol/water solvent. ETAAS detection is performed on-line using an oxidizing matrix modifier. Mono-, di- and tri-butyltin may be determined in a single experiment with detection limits of (respectively) 0.5, 1.1 and 0.8 ng (Sn). Applications to actual samples are reported.     

Simultaneous determination and pharmacokinetic study of giraldoid a,giraldoid B in rat plasma after oral administration of Daphne giraldii Nitsche extracts by LC–MS/MS

A simple sensitive LC–MS/MS method has been developed for the simultaneous determination of giraldoid A and giraldoid B in rat plasma. The method was applied to pharmacokinetics studies of the two compounds from Daphne giraldii Nitsche. Chromatographic separation was accomplished on an Acquity UPLC™ BEH C₁₈ column (100 × 2.1 mm, 1.7 mm) by gradient elution with a flow rate of 0.2 mL min⁻¹_. The method was linear over the concentration range of 1.0–1000 ng mL⁻¹, and the lower limits of quantification were 1.04 ± 0.10 and 1.04 ± 0.09 ng mL⁻¹, respectively. The intra‐ and inter‐day precisions (RSD) were <10.14 and 9.96%. The extraction recovery of the analytes was acceptable. Stability studies demonstrated that the two compounds were stable in the preparation and analytical process. The maximum plasma concentration was 687.78 ± 243.62 ng mL⁻¹ for giraldoid A and 952.38 ± 131.99 ng mL⁻¹ for giraldoid B. The time to reach the maximum plasma concentration was 0.50 ± 0.37 h for giraldoid A and 0.50 ± 0.66 h for giraldoid B. The validated method was successfully applied to investigate the concentration–time profiles of giraldoid A and giraldoid B.     

Simultaneous Determination of Aluminum,Cadmium and Lead in Whole Blood by Simultaneous Atomic Absorption Spectrometry with Oxygen Charring

A method for the simultaneous determination of aluminum (Al), cadmium (Cd) and lead (Pb) in whole blood has been developed by using simultaneous atomic absorption spectrometry (SIMAAS) with oxygen charring. The optimized conditions for the simultaneous determination of Al, Cd and Pb were obtained in the presence of palladium (Pd) as the chemical modifier, using 600 °C and 2400 °C as the pyrolysis and the atomization temperature, respectively. The whole blood samples were diluted 1+5 (v/v) directly with 0.1% (v/v) Triton X‐100. Oxygen was employed to eliminate the interference of carbonaceous residues in the charring step before pyrolysis. The calibration curves were carried out with aqueous standard solutions and the linear ranges were 0–40 ng mL⁻¹, 0–4 ng mL⁻¹ and 0–40 ng mL⁻¹ for Al, Cd and Pb, respectively. The detection limits were 0.96 ng mL⁻¹ (19.2 pg) for Al, 0.03 ng mL⁻¹ (0.6 pg) for Cd and 0.60 ng mL⁻¹ (12.0 pg) for Pb. The spiked recoveries of Al, Cd and Pb in whole blood were 98.0%, 100.0% and 101.7%, respectively. The accuracy of the proposed method was evaluated with the analysis of a whole blood certified reference material (Seronorm, level 2). The found concentrations were in agreement with the recommended values. The proposed method has been successfully applied to the simultaneous determination of Al, Cd and Pb in whole blood of healthy volunteers before and after eating barbecued foods.     

Determination of Hg in seawater by inductively coupled plasma mass spectrometry after on-line pre-concentration

A method for the determination of Hg in seawater by inductively coupled plasma mass spectrometry, after an on-line separation and pre-concentration, is described. The matrix separation was accomplished by retention of the Hg complex with the ammonium salt of O,O-diethyl dithiophosphoric acid on C₁₈ immobilized on silica in a micro-column. Before pre-concentration, the seawater sample was acidified with HNO₃ to 0.14 mol l⁻¹. Methanol was used as the eluent, which was introduced into the conventional pneumatic nebulizer of the instrument. External calibration with aqueous analytical solutions, submitted to the same procedure, was used. An enhancement factor of 16 was obtained, and the limit of detection was 5 ng l⁻¹. The sample consumption was 2.3 ml per determination, and the sampling frequency was 21 h⁻¹. The accuracy was tested by comparison with vapor generation inductively coupled plasma mass spectrometry. The agreement between the Hg concentrations measured by the two methods in the seawater samples was good.     

Isotope dilution analysis mass spectrometry for the routine measurement of butyltin compounds in marine environmental and biological samples

The highly qualified primary method of species-specific isotope dilution analysis has been employed in this work to evaluate for the first time the levels of butyltin compounds in the estuary of the river Eo (Northwest Spain) where there is, since many years, a high oyster farming activity. A spike solution containing mono-, di- and tributyltin enriched in ¹¹⁹Sn allowed the simultaneous determination of the three compounds in different marine environmental and biological samples collected in this area (seawater samples, sediments and biological tissues of four different marine species). The results obtained in this work showed toxic TBT levels for many marine species in 45% of the seawater samples analyzed whereas significant organotin concentrations were found to be obtained only in one of the sediments analyzed. On the other hand, TBT levels ranging from 20 to almost 200 ng g^− 1 (dry weight) were obtained in the different biological tissues analyzed demonstrating the bioaccumulation of organotin compounds in certain marine species.     

Simultaneous speciation of mercury and butyltin compounds in natural waters and snow by propylation and species-specific isotope dilution mass spectrometry analysis

A robust method has been developed for simultaneous determination of mercury and butyltin compounds in aqueous samples. This method is capable of providing accurate results for analyte concentrations in the picogram per liter to nanogram per liter range. The simultaneous determination of the mercury and tin compounds is achieved by species-specific isotope dilution, derivatization, and gas chromatography–inductively coupled plasma mass spectrometer (GC–ICP–MS). In derivatization by ethylation and propylation, reaction conditions such as pH and the effect of chloride were carefully studied. Ethylation was found to be more sensitive to matrix effects, especially for mercury compounds. Propylation was thus the preferred derivatization method for simultaneous determination of organomercury and organotin compounds in environmental samples. The analytical method is highly accurate and precise, with RSD values of 1 and 3% for analyte concentrations in the picogram per liter to nanogram per liter range. By use of cleaning procedures and SIDMS blank measurements, detection limits in the range 10–60 pg L^–1 were achieved; these are suitable for determination of background levels of these contaminants in environmental samples. This was demonstrated by using the method for analysis of real snow and seawater samples. This work illustrates the great advantage of species-specific isotope dilution for the validation of an analytical speciation method—the possibility of overcoming species transformations and non-quantitative recovery. Analysis time is saved by use of the simultaneous method, because of the use of a single sample-preparation procedure and one analysis.     

Determination of organotin compounds (OTC) at low levels in seawater by solid-phase extraction (SPE) and gas chromatography-pulsed flame photometric detection (GC-PFPD)

In this work, a simple, sensitive and affordable analytical method for the simultaneous determination of nine organotin compounds (butyltins, phenyltins and methyltins) in seawater using solid-phase extraction (SPE) and gas chromatography-pulsed flame photometric detection was developed and validated. The performance of three different SPE cartridges (Envi C₁₈, Oasis HLB and Oasis MCX) and three elution solvents of different polarity (hexane, methanol and acetonitrile) was evaluated. The extraction parameters, such as solvent volume, presence of complexing and ion-pairing reagents, sample volume and pH and breakthrough volume, were also investigated. Tributyltin, as the organotin compound of special interest, was efficiently extracted using any of the cartridges and solvents tested. However, the simultaneous extraction of all nine organotin compounds was the most efficient using reversed-phase Envi C₁₈ cartridge and 0.1% (w/v) tropolone in methanol as eluent. The optimised method resulted in good recovery, precision and linearity for all compounds, particularly for tri- and disubstituted species. Method detection limits ranged from 0.22 to 1.27 ng(Sn) L^?1 for butyltins, 0.37 to 4.91 ng(Sn) L^?1 for phenyltins and 0.45 to 1.16 ng(Sn) L^?1 for methyltins. The accuracy of butyltins determination was further verified by the comparison with purchased derivatised standards. The developed method was successfully applied to the environmental samples.     

Simultaneous butyltin determinations in the microlayer,water column and sediment of a northern Chesapeake Bay marina and receiving system

Butyltins were determined in the microlayer, water column and sediment of a northern Chesapeake Bay marina and its receiving system. Concentrations of the toxicant species tributyltin (TBT) ranged from 60 to 4130 ng dm⁻³ in the microlayer, from 34 to 367 ng dm⁻³ in the water column and from <0.05 to 1.4 m̈g g⁻¹ (dry weight) in sediment. TBT concentrations in all three environmental compartments were higher in the marinas than in the receiving system. Concentrations of TBT in the microlayer and water column of the study area were potentially toxic to sensitive aquatic biota. The microlayer appears to be depleted in dibutyltin relative to tributyltin compared to both water column and sediment.     

Determination of natural and synthetic estrogenic compounds in coastal lagoon waters by HPLC-electrospray-mass spectrometry

A new analytical method was developed for the simultaneous determination of estrogenic compounds of natural (estradiol, estriol, estrone) and synthetic origin, both steroidal (ethinylestradiol, mestranol) and non-steroidal (benzophenone, bisphenol-A, diethylstilbestrol, octylphenol, nonylphenol, nonylphenol monoethoxylate carboxylate), in environmental aqueous samples by high-performance liquid chromatography coupled with ion trap-mass spectrometry via electrospray interface (HPLC-ESI-IT-MS). Quantitative MS detection was performed in the negative mode for all compounds except mestranol and benzophenone, which were detected under positive ion conditions. Very low method detection limits (MDLs), between 0.1 and 2.6?ng/L, were achieved in coastal lagoon water samples, while the developed solid-phase-extraction (SPE) procedure permitted simultaneous recovery of all analytes from spiked water samples with yields >70% (7–11 RSD%), except estriol and benzophenone, which were recovered with 60% (9 RSD%) and 50% (11 RSD%) yields, respectively. The proposed method was applied to the analysis of Venice (Italy) lagoon waters, where average concentrations of selected compounds in the 2.8–33?ng/L concentration range were found.