In situ ethylation of organolead,organotin and organomercury species by bromomagnesium tetraethylborate prior to GC‐ICP‐MS analysis

An analytical method for simultaneous in situ ethylation, of organolead, organotin and organomercury compounds in aqueous samples was developed using a new derivatisation agent, bromomagnesium tetraethylborate (BrMgEt₄B). The determination of lead, tin and mercury compounds was done by species‐specific isotope dilution, derivatisation and GC–inductively coupled plasma MS (GC‐ICP‐MS) or by GC‐MS. The recovery and accuracy of the derivatisation were evaluated. The effect of pH and the relative quantity of derivatisation agent were studied.     

Ethylation of methylarsenic(III) compounds by sodium tetraethylborate

The compounds MeAsBr₂ and Me₂AsBr at concentrations of (1–5) × 10^?3 M in acetone solution are ethylated in high yield by NaBEt₄ to MeEt₂As and Me₂EtAs, as shown by ¹H NMR spectroscopy. The extents of ethylation of MeAs²⁺ and Me₂As⁺ (expressed as ions, by convention) in aqueous acid solutions [at concentrations of (5–20) × 10^?6 M ] were investigated using cold trap/AA and GC AA procedures. The species Me₂As⁺ was ethylated (to give Me₂EtAs) in good yield (88%); in contrast, MeAs²⁺ produced the volatile trialkylarsine, MeEt₂As, in poor yield (30%). No volatile trialkylarsine could be obtained on treating inorganic arsenic(III) (As³⁺) solutions with NaBEt₄.     

Determination of butyl- and phenyltin compounds in biological material by gas chromatography-flame photometric detection after ethylation with sodium tetraethylborate

A reliable and rapid speciation method for the simultaneous determination of butyl- and phenyltin species in biological samples has been developed. Three extraction procedures are compared: enzymatic hydrolysis and solubilization by ethanoic and hydrochloric acids. Derivatization is performed by the one-step ethylation/extraction procedure using the sodium tetraethylborate reagent directly in the aqueous phase in the presence of an isooctane layer. Analysis is performed using capillary gas chromatography coupled to flame photometric detection. The detection limits are in the range of a few ng(Sn)/g. Analysis of the environmental samples and the certified reference material demonstrates the accuracy of the analytical method.     

The use of sodium tetraethylborate for the derivatization and analysis of selenium containing compounds

Several selenium containing compounds have been derivatized to diethyl selenide using sodium tetraethylborate. The evolved diethyl selenide was detected by gas chromatography interfaced with atomic absorption or mass spectroscopic methods. Derivatization was carried out on the analyte in a sealed vial using an aqueous solution of sodium tetraethylborate (2%) added by means of a syringe.     

Simplified sample preparation for GC speciation analysis of organotin in marine biomaterials

Two simple sample preparation methods for the speciation analysis of triphenyltin and butyltin compounds in marine biotissues, using tetramethylammonium hydroxide (TMAH) solubilization and enzymic hydrolysis, have been developed and compared with conventional acid digestion. Derivatization was carried out in situ using sodium tetraethylborate (NaBEt₄) without prior separation of the analytes from the tissue matrix. Separation and detection was performed using capillary gas chromatography (GC) coupled to microwave-induced plasma atomic emission spectrometry (MIP AE) allowing detection limits of 2 ng g^?1 (as tin) to be reached. The accuracy of the presented methods was demonstrated by the analysis of a fish reference material (NIES No. 11). the necessity for sample clean-up is discussed and examples of the analysis of mussel tissue are shown.     

Speciation of butyltin compounds by on line HPLC-ETAAS

Speciation of butyltin compounds by liquid chromatography coupled to electrothermal atomic absorption spectrometry of toluene solutions containing tropolone is applied to sediment samples. Tributyltin and dibutyltin may be determined at concentrations as low as a few ng · g^–1. Monobutyltin is strongly retained, tetrabutyltin is not separated from tributyltin.     

Speciation and GC retention indices of some organotin compounds in water

Analytical methods have been developed for the quantitative determination of Bu₄Sn, Bu₃Sn⁺, Bu₂Sn²⁺, BuSn³⁺, Me₃BuSn, Me₂Bu₂Sn, MeBu₃Sn, MeBuSn²⁺, Me₂BuSn⁺ and MeBu₂Sn⁺ in water. Organotin compounds are extracted from water with tropolone at 0.1 % in n-pentane, derivatized with n-pentylmagnesium bromide and determined by gas chromatography with flame photometric detection or flame ionization detection. Absolute detection limits are 0.05-0.12 ng and 1.2-13 ng as tin, respectively. The method was applied to the analysis of spiked tap-water containing 0.3-1000 ng cm^?3 of each of the organotin compounds.     

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.     

Acid extraction treatment of sediment samples for organotin speciation; occurrence of butyltin and phenyltin compounds on the cadiz coast,south-west spain

A method is described for leaching of nanogram amounts of mono-, di and tri-butyltin compounds and mono-, di- and tri-phenyltin compounds from sediments. The procedure is based on soaking the sediments in a water–hydrogen bromide mixture (2:3) with magnetic stirring for 1 h followed by extraction with 0.02% (w/v) tropolone solution in pentane for 2 h. Organotins are determined by GF FPD after clean-up through a Florisil column and derivatization by Grignard pentylation. The method has been applied to the study of water and sediments in different areas of south-west Spain. Predominant species are butyltins, especially tributyltin (TBT), which has high values in waters and sediments of Puerto de Santa Maria and Cadiz Bay, as well as in sediments of the Sancti Petri Channel, which suggests a harmful action on biota. A direct relation has been found beween organotin levels and distance of potential focus determined by boating activities. In addition, the relative occurrence of dibutyltin (DBT) and monobutyltin (MBT) together with TBT has been noted, possibly as a result of a degractation process, and the influence of grain size of sediment and presence of organic matter on organotin accumulation has been studied.     

Speciation of alkyllead compounds by GC-AAS: A state of affairs

A synopsis of the organolead studies performed at our University is given. The different environmental applications such as air, wet atmospheric deposition and dust are summarized and the analytical characteristics of the extraction/derivatization/gas chromatography—atomic absorption spectrometry methodology for the species specific determination of ionic alkyllead species are described.     

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.     

Comparison of tetraethylborate and tetraphenylborate for selenite determination in human urine by gas chromatography mass spectrometry, after headspace solid phase microextraction

Two different derivatizing reagents were tested for the development of a fast and sensitive method for the determination of selenites (Se^IV) in human urine. The reagents were sodium tetraethylborate (NaBEt₄) and tetraphenylborate (NaBPh₄), respectively, and the procedure is based on in situ derivatization of selenites in aqueous medium. Selenite ions are converted to diethylselenide (DESe) or diphenylselenide (DPhSe) and subsequently collected from the headspace by solid phase microextraction using a silica fiber coated with polydimethylsiloxane (HS-SPME). Finally, they are quantitated by GC/MS in SIM mode. Ethylation over phenylation was proved preferable for the headspace extraction because of the higher volatility of the diethyl-derivative of selenites. The optimization of the HS-SPME conditions was performed both in aqueous and urinary solutions. Under the optimum conditions for HS-SPME, the gas chromatographic conditions were also optimized. Between the two alkylation reagents tetraethylborate was proved more efficient and the quantitation was satisfactory. Aqueous certified reference materials were analyzed to evaluate the accuracy of the method. The precision of the method was 4.2% and the calculated detection limit was 0.05 μg L⁻¹ for human urine.     

型煤中硫的还原热解MS和GC/MS分析

以煤和生物质为主要原料的商用型煤为研究对象,采用还原热解（AP-TPR）在线质谱（MS）联用,以及离线色谱/质谱（GC/MS）分析法,定性和定量研究了家用型煤释放的含硫化合物。不同组成的型煤表现出各自不同的硫释放特性。对于生物型煤来说,仅检测到少量二烷基硫醚和脂肪硫醇的存在。褐煤型煤检测到种类最多的有机硫化物。在高阶煤制成的型煤中没有检测到氧化态的硫化物,其典型特征是存在一些噻吩类硫化物。     

Speciation of organotin compounds in water and sediments by gas chromatography/atomic absorption spectrometry (GC-AAS)

A commercially available atomic absorption detector coupled to a wide-bore column-containing gas Chromatograph (GC-AAS) was utilized to detect organotin compounds. Speciation was performed by pentane extraction of the organotin species as the corresponding sodium diethyldithiocarbamate complexes, enrichment by rotary evaporation, derivatization with Grignard reagent and finally the extracted water and sediment samples were separated and detected on the GC-AAS system.     

Determination of butyl- and phenyltin compounds in human urine by HS-SPME after derivatization with tetraethylborate and subsequent determination by capillary GC with microwave-induced plasma atomic emission and mass spectrometric detection

A headspace solid-phase micro-extraction (HS-SPME) method was developed and optimized for gas chromatographic separation and determination of commonly found organotin compounds in human urine after potential exposure. Butyl- and phenyltin compounds were in situ derivatized to ethylated derivatives by sodium tetraethylborate (NaBEt₄) directly in the urine matrix. The relevant parameters affecting the yield of the SPME procedure were examined using tetrabutyltin as internal standard. The method was optimized for direct use in the analysis of undiluted human urine samples and mono-, di- and tri-substituted butyl- and phenyltin compounds could be determined after a 15-min headspace extraction time at room temperature. The selectivity of the microwave-induced plasma atomic emission detector (MIP-AED) as an element specific detector in combination with the relatively selective sample preparation technique of HS-SPME allowed the interference-free detection of the organotin compounds in all cases. A quadrupole mass spectrometer was used in parallel experiments as a detector for the confirmation of the identity molecular structure of the eluted compounds. The performance characteristics of the developed method are given for the determination of mixtures of these compounds. Finally the proposed method was applied to the analysis of several human urine samples.     

Arsenic speciation in some environmental samples: a comparative study of HG–GC–QFAAS and HPLC–ICP–MS methods

Some water and soil extracts polluted with arsenic, and a sewage sludge certified for total arsenic have been analysed by high‐performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC–ICP–MS) and hydride generation–gas chromatography– quartz furnace atomic absorption spectrometry (HG–GC–QFAAS techniques.) Detection limits in the range of 200–400 and 2–10 ng l⁻¹ respectively allowed the determination of inorganic [As(III), As(V)] and methylated (DMA, MMA, TMAO) arsenic species present in these samples. Results obtained by both methods are well correlated overall, whatever the arsenic chemical form and concentration range (8–10 000 μg l⁻¹). Comparison of these results enabled us to point out features and disadvantages of each analytical method and to reach a conclusion that they are suitable for arsenic speciation in these environmental matrices. Copyright © 2000 John Wiley & Sons, Ltd.     

Application of gas chromatography–tandem mass spectrometry (GC/MS/MS) for the analysis of deuterium enrichment of water

Incorporation of deuterium from deuterium oxide (²H₂O) into biological components is a commonly used approach in metabolic studies. Determining the dilution of deuterium in the body water (BW) pool can be used to estimate body composition. We describe three sensitive GC/MS/MS methods to measure water enrichment in BW. Samples were reacted with NaOH and U‐¹³C₃‐acetone in an autosampler vial to promote deuterium exchange with U‐¹³C₃‐acetone hydrogens. Headspace injections were made of U‐¹³C₃‐acetone‐saturated air onto a 30‐m DB‐1MS column in electron impact‐mode. Subjects ingested 30 ml ²H₂O, and plasma samples were collected. BW was determined by standard equation. Dual‐energy X‐ray absorptiometry scans were performed to calculate body mass, body volume and bone mineral content. A four‐compartmental model was used to estimate body composition (fat and fat free mass). Full‐scan experiments generated an m/z 45 peak and to a lesser extent an m/z 61 peak. Product fragment ions further monitored included 45 and 46 using selected ion monitoring (Method1), the 61 > 45 and 62 > 46 transition using multiple reaction monitoring (MRM; Method2) and the neutral loss, 62 > 45, transition (Method3). MRM methods were optimized for collision energy (CE) and collision‐induced dissociation (CID) argon gas pressure with 6 eV CE and 1.5 mTorr CID gas being optimal. Method2 was used for final determination of ²H₂O enrichment of subjects because of lower natural background. We have developed a sensitive method to determine ²H₂O enrichment in BW to enable measurement of FM and FFM. Copyright © 2015 John Wiley & Sons, Ltd.     

Speciation analysis of arsenic compounds in edible oil by ion chromatography-inductively coupled plasma mass spectrometry

An inductively coupled plasma mass spectrometer (ICP-MS) was used as an ion chromatographic (IC) detector for the speciation analysis of arsenic in edible oil. The arsenic species studied include arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine. Gradient elution using (NH(4))(2)CO(3) and methanol at pH 8.5 allowed the chromatographic separation of all species in less than 8 min. Effluents from the IC column were delivered to the nebulizer of ICP-MS for the determination of arsenic. The concentrations of arsenic species have been determined in several used and fresh vegetable oil samples. In this study, a microwave-assisted extraction method was used for the extraction of arsenic species from oil samples. The extraction efficiency was better than 92% and the recoveries from spiked samples were in the range of 90-105%. The precision between sample replicates was better than 8% for all determinations. The limits of detection were in the range of 0.008-0.024 ng mL(-1) for various arsenic species based on peak height, which corresponded to 0.08-0.24 ng g(-1) in the original oil sample. The major arsenic species in the used oil samples varied based on the food items cooked.