Μg Sn Research Articles

Extractive Spectrophotometric Detection of Sn(II) Using 6-bromo-3-hydroxy-2-(5-methylfuran-2-yl)-4H-chromen-4-one.

For the determination of tin(II) traces, an extractive spectrophotometric approach is devised. The applied method serves a powerful tool for determination of tin(II), involves the formation of yellow colored complex after thebinding of 6-bromo-3-hydroxy-2-(5-methylfuran-2-yl)-4H-chromen-4-one (BHMF) and tin(II) in 1:2 stiochiometry in a slightly acidic medium (HCl). The complex shows absorbance at 434nm with respect of the blank reagent. The outcomes of spectral investigation for complexation showed a Beer's range of 0-1.3μg Sn mL-1, molar absorptivity, specific absorptivity and Sandell's complex sensitivity are 9.291 × 104 L mol-1cm-1, 0.490mLg-1cm-1 and 0.002040μgcm-2 at 434nm that was stable for two days. The interferences studyresults showed that this method is free from interferences, when tested with metal ions including Ag,Be, Bi, Ca,Cd, Ce, Co,Hg, Mo,Re,Pt, Se,Ti,U,V, W and other common cations, anions, and complexing agents. Theapplied method is quite simple, highly selective, and sensitive with good re-producibility. This method has been satisfactorily by utilizing the proposed procedure, and its applicability has been tested by analyzing synthetic samples and an alloy sample of gunmetal. The procedure assumes this because of the scarcity of better methods for determining tin(II). The results are in good agreement with the certified value.

Electrodeposition and characterization of Sn on Re filaments for laser resonance ionization mass spectrometry.

The isotopic analysis of Sn is crucial for geochemical research and surveillance of nuclear contamination. However, commonly used methods face the challenge of isobaric interference. Laser resonance ionization mass spectrometry (LRIMS) is a promising technology for effectively eliminating the isobaric interference effect as it combines the advantages of both resonance ionization and mass spectrometry technologies. In this study, an atomic source of 1 μg Sn was prepared by electrodeposition on a Re filament in a 1-5 × 0.7 mm spot for LRIMS measurement. The effects of voltage, duration, length of the active area, and Pb content on the deposition yield were studied, and the morphology, composition, and valence of the Sn deposits were examined. A maximum yield of over 90% in a 3 × 0.7 mm spot was achieved through the surface modification of Re filaments and optimisation of the electrodeposition parameters. As the Sn0 atomic state was predominant in the deposit, the average detection efficiency of the LRIMS device using the as-deposited Sn samples was approximately 3.63 × 10-4, which was almost an order of magnitude higher than that of the sample dropped with graphene oxide solution (4.39 × 10-5).

Occurrence of organotin compounds in seafood from Hong Kong market

The degree of organotin compounds (OTCs), including dibutyltin, tributyltin, triphenyltin and dioctyltin, contamination in seafood purchased in 2017 and 2018 from Hong Kong market was studied. Edible portions of 341 seafood samples, including fish, crustaceans and molluscs, were used for analysis by gas chromatograph coupled to an inductively coupled plasma mass spectrometry (GC-ICP/MS). The method detection limits and quantification limits of OTCs were below or equal to 0.25 and 1.0 μg Sn kg−1 respectively. Triphenyltin accounted for the majority amongst other OTCs and was detected in 53% of samples. In general, mean total OTCs levels of fish (24 μg Sn kg−1) were higher than crustaceans (14 μg Sn kg−1) and molluscs (15 μg Sn kg−1). The highest detected levels of triphenyltin, tributyltin, dibutyltin and dioctyltin were found to be 480, 24, 4.5 and 0.89 μg Sn kg−1 in a mangrove snapper, noodle fish, coral clam and giant grouper respectively.

Development of a Robust and Sensitive Method for Analyzing Butyltins, Phenyltins and Octyltins in Seafood

A new method has been developed and validated for determination of ten organotin compounds (OTCs), including butyltins, octyltins, phenyltins, and tricyclohexyltin, in seafood that preserved the moiety of individual OTCs. The optimized method started with extraction of OTCs by acidified methanol solution and then cleaned up with Florisil solid-phase extraction (SPE). The OTCs in extract were finally derivatized with sodium tetraethylborate. The instrumental determination was carried out by a gas chromatograph coupled to an inductively coupled plasma mass spectrometer (GC-ICP/MS). Besides, gas chromatograph tandem mass spectrometry was also studied and evaluated for OTCs’ sensitivities. The method was validated with various seafood samples, including fishes, crustaceans and mollusks, according to Eurachem guidelines. An adequate linear relationship was obtained in the studied concentration range (0.125–12.5 μg Sn kg−1) in samples; the average spiked recovery values were in the range of 70–120% for the three levels of concentration studied in samples: 1.0, 1.5, and 2.0 μg Sn kg−1. Precision values, expressed as relative standard deviation, were lower than 10% at aforementioned spiking levels. The detection limits and quantification limits were below or equal to 0.25 and 1.0 μg Sn kg−1, respectively. Besides, certified reference material was used to assess the accuracy of the developed method. The developed method was successfully applied for the OTC determination in real samples.

Trace analysis of butyltin compounds in seawater of some west Algerian harbors by gas chromatography-mass spectrometry

ABSTRACTAn analytical gas chromatography-mass spectrometry (GC-MS) method was investigated for the determination of trace butyltin compounds (BTs) (tributyltin [TBT] and its derivatives dibutyltin [DBT] and monobutyltin [MBT]) in seawater collected from some west Algerian harbors. BTs were detected in all samples from all investigated sites. Levels of total BT concentrations detected in seawater ranged from 0.045 to 0.798 μg Sn L−1. Higher concentrations of BTs were found in seawater collected from Bethioua (0.798 μg Sn L−1), an oil terminal, and Mers El Kébir shipyard (0,585 μg Sn L−1). This suggested that maritime activities close to the harbors play a major role as the source of BTs. Indeed, the harbor of Bethioua is frequented by many tankers. TBT was the predominant compound in seawater collected from almost all the sampling locations, indicating the fresh input of TBT in the harbors.

Evaluation of cloud point extraction coupled with fluorescence spectroscopy and multivariate curve resolution–alternating least squares for tributyltin determination in sediment samples

In this work, a new procedure for tributyltin (TBT) detection in marine sediments based on cloud point extraction (CPE) followed by total fluorescence spectroscopy combined with multivariate curve resolution–alternating least squares (MCR–ALS) is proposed. The multivariate model satisfactorily achieved the second order advantage in the presence of uncalibrated interferences, such as butyltin compounds or metallic species that are commonly found in sediment sample extracts. Under optimal conditions, the detection limit reached 3.0μg Sn L−1, and the relative prediction error was lower than 10%. The accuracy of the method was validated with the analysis of a certified sediment sample (marine sediment PACS-2), and there was good agreement between the certified and experimental results. Finally, the proposed methodology was satisfactorily applied to spiked real sediment samples, demonstrating the suitability of the proposed method for TBT detection in contaminated sediment samples.

A Rapid Extractive Spectrophotometric Method for the Determination of Tin with 6-Chloro-3-hydroxy-2-(2′-thienyl)-4-oxo-4H-1-benzopyran

An extractive spectrophotometric method for the determination of the trace amounts of tin has been carried out by employing 6-chloro-3-hydroxy-2-(2′-thienyl)-4-oxo-4H-1-benzopyran (in acetone) (CHTB) for the complexation of the metal ion in HCl medium. The colored species thus produced is quantitatively extracted into dichloromethane and shows the maximum absorbance at 432–437 nm. The method obeys Beer’s law in the range 0.0–1.3 μg mL−1 of tin with molar absorptivity and Sandell’s sensitivity of 5.81×104 L mol−1 cm−1 and 0.0020 μg Sn cm−2, respectively, at 435 nm. The method is highly selective and free from the interference of a large number of elements including platinum metals. The ratio of metal to ligand in the extracted species is 1 : 2. Utilizing this method, the analysis of various synthetic and technical samples including gun metal and tin can have been carried out satisfactorily.

Transformation of methyltin chlorides and stannic chloride under simulated landfill conditions

There is increasing concern regarding the fate of methyltins in the environment, particularly since large amounts of polyvinyl chloride (PVC) plastics are deposited in landfills. The potential transformation of methyltin chlorides and stannic chloride in landfills was investigated, by incubating the target substances at concentrations relevant to landfill conditions (100 and 500 µg Sn L(-1)). The amounts of methane formed in all treatment bottles, and controls, were measured to evaluate the general microbial activity of the inocula and possible effects of methyltins on the degradation of organic matter. The methyltins and stannic chloride were found to have no significant inhibitory effects on the activity of landfill micro-organisms, and the methanol used to disperse the tin compounds was completely degraded. In some experimental bottles, the methanol degradation gave rise to larger methane yields than expected, which was attributed to enhanced degradation of the waste material. Alkyltin analyses showed that monomethyltin trichloride at an initial concentration of 500 µg Sn L(-1) promoted methylation of inorganic tin present in the inoculum. No methylation activities were detected in the incubations with 100 µg Sn L(-1) methyltin chlorides (mono-, di- or tri-methyltin), but demethylation occurred instead. Levels of soluble inorganic tin increased during the incubation period, due partly to demethylation and partly to a release of tin from the waste inocula.

Simultaneous determination of mercury and butyltin species using a multiple species-specific isotope dilution methodology on the European, Anguilla anguilla glass eel and yellow eel

A methodology to simultaneously determine mercury (MeHg, IHg) and butyltin (TBT, DBT, MBT) compounds in eel samples was assessed and validated using multiple isotopically enriched species. The developed methodology was able to analyse simultaneously the organometal species accurately and precisely and to correct for the potential transformations/degradations of the different species during the various steps of the analytical procedure. Low detection limits were achieved (0.007–0.17 µg Hg kg−1 for mercury (Hg) species and 0.42–0.71 µg Sn kg−1 for tin (Sn) species) allowing analysis of low-mass samples and thus the analysis at the individual organism scale, including glass eels for which samples dry weight ranged from 60 to 100 mg. The methodology was validated with certified reference materials (BCR-464, BCR-477, BCR-710, DOLT-4 and NIST-2977) and applied to the analysis of these pollutants in two developmental stages of the European eel, Anguilla anguilla: individual whole glass eels and muscle tissue from yellow eels. The Adour estuary (South-west France) was selected to monitor the bioaccumulation of organometal species in these organisms, according their developmental stage, their morphological parameters and the sampling site. The results suggest that the accumulation of methylmercury in glass eel tissue is related to weight, with higher concentrations in smaller individuals. Butyltin concentrations were very close to the limit of detection, and no significant differences were detected between glass and yellow eels.

Butyltin compounds in vinegar collected in Beijing: Species distribution and source investigation

Forty-eight vinegar samples including white vinegar, rice vinegar and mature vinegar were collected from several markets in Beijing. Butyltin compounds were determined by headspace solid-phase microextraction coupled with gas chromatography and flame photometric detector after in situ ethylation with sodium tetraethylborate. Butyltin species were detected in sixteen vinegar samples and ranged from 0.012 to 14.10 μg Sn L−1. The detection rate of white vinegar is higher than that of rice vinegar and mature vinegar. Vinegar samples with relatively high butyltin concentration (>1.5 μg Sn L−1) were those stored in plastic bags, indicating that the plastic bag was one of the possible sources of butyltin contamination. This was further confirmed by the leaching experiments of three selected plastic bags, and monobutyltin was detected in the leaching solvents. According to the estimation, the average daily intake of total butyltin compounds through vinegar consumption is about 0.04 ng Sn/kg b.w., much lower than the Tolerable Daily Intake (TDI) of 100 ng Sn/kg b.w. set by the European Food Safety Authority (EFSA).

Contamination of outdoor settled dust by butyltins in Malta

AbstractThe presence of compounds of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) was determined in outdoor settled dust collected from several sites on the island of Malta, mainly from flat rooftops of school buildings. The dust was separated into three size fractions with diameters (µm) > 250, 125–250 and < 125, and the two finer fractions were analysed for butyltins using extraction with glacial acetic acid followed by derivatization/solvent extraction with sodium tetraethylborate in the presence of iso‐octane and quantitation by gas chromatography with flame photometric detection. The presence of TBT, DBT and MBT was established in most of the samples and TBT concentrations varied from non‐detectable (<5 ng Sn g−1) to highs of 15.5 and 18.7 µg Sn g−1 in Senglea and Marsaxlokk. TBT was generally found at concentrations significantly higher than reported hitherto in house dust collected from European homes. The geographical distribution of total organotins in both dust fractions suggests that TBT originates mainly from antifouling marine paint residues which contaminate the urban environment when ships' hulls are sand‐ or hydro‐blasted during maintenance and repair at the drydocks facility in Grand Harbour. Other significant sources of TBT are located at Marsaxlokk fishing port and Wied iż‐Żurrieq creek, both hosting sizeable communities of fishermen and leisure boating. The data also suggest that the municipal solid waste landfill at Maghtab is an inland source of butyltins. We suggest that dust containing harmful butyltins could possibly be ingested to expose humans to a risk which is probably of concern especially for young children living close to the hotspots of contamination. Copyright © 2007 John Wiley & Sons, Ltd.

Preparation of 99mTc-cefoperazone complex, a novel agent for detecting sites of infection

Prompt localization of infection sites is essential for initiating appropriate therapeutic measures. There have been major advances in the management of patients suffering from infective and/or inflammatory disorders as a result of introduction of newer drugs with high sensitivity and specificity. Since the last decade, 99mTc-ciprofloxacin was used as a biologically active radiopharmaceutical to diagnose inflammation but it has some problems related to radiochemical purity and stability. The aim of this study is to develop simple and easy formulation of cefoperazone (other broad spectrum antimicrobial agent) with 99mTc a ready to use labeling kit for infection imaging. The optimum condition that gives high labeling yield of 99mTc-cefoperazone complex, 97.9%, was achieved by using 3 mg cefoperazone, 100 μg Sn(II), at pH 8 and 10-minute reaction time. For in vivo binding of 99mTc-cefoperazone pharmacokinetic studies were carried in experimentally induced infection, in the left thigh, using Staphylococcus aureus in rats. Both thighs of the rats were dissected and counted and the ratio of bacterial infected thigh/contralateral thigh was then evaluated. The time for maximum accumulation of 99mTc-cefoperazone at the site of infection (T/NT = 4.5) was 45-minute post intravenous injection, followed by gradual decline. So, 99mTc-cefoperazone complex is simple and stable preparation for infection imaging after 45-minute post injection.

Biosorption and biodegradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris beads in several treatment cycles

Biosorption and biodegradation by microorganisms to remove tributyltin (TBT), a toxic and persistent contaminant, have attracted more and more interests in recent years but information related to microalgae is still inadequate. The present study aims to investigate the removal and degradation of TBT at 10, 50 and 100 μg Sn l −1 contamination levels by alginate-immobilized Chlorella vulgaris beads during six consecutive cycles (4 days each), and compare the performance with blank alginate beads (without algae). More than 90% of TBT was rapidly removed, within 1 day, by both algal and blank beads, irrespective to the spiked TBT concentrations and the number of cycles, indicating the initial removal was mainly by biosorption and alginate matrix provided many binding sites. For algal beads, TBT was mostly adsorbed onto alginate matrix with some on algal cell walls, and <10% of the spiked TBT accumulated inside cells. The amounts of debutylated products, dibutyltin (DBT) and monobutyltin (MBT) in medium increased gradually with treatment cycles and with the spiked TBT concentrations. At the contamination levels of 50 and 100 μg Sn l −1, both DBT and MBT in algal bead treatments increased to >5 μg Sn in cycle 6 while little DBT and MBT were detected in blank beads throughout the cycles. The accumulation of DBT and MBT, same as TBT, inside cells was relatively small compared to that in medium and alginate matrix. For the high TBT level of 100 μg Sn l −1, 60% of the spiked TBT was biodegraded by algal beads at the end of the six cycles. These results suggested that the alginate immobilized alga, C. vulgaris was able to continuously detoxify TBT into DBT and MBT for six consecutive cycles even at the highest TBT contamination level.

A highly selective and sensitive extractive spectrophotometric determination of tin(II) using 6-chloro-3-hydroxy-2-phenyl-4- oxo-4H -1-benzopyran as a complexing agent

An extractive spectrophotomctric method is developed for the trace determination of tin. A yellow 1: 2 (M: L) complex of tin(II) is formed with 6-chloro-3-hydroxy-2-phcnyl-4-oxo-4H-1-benzopyran (CHPB) in HCl medium. The coloured species is quantitatively extracted into carbon tetrachloride and shows maximum absorbance at 411-417 nm. The method obeys Beer's law in the range 0-2.0 μg ml -1 with molar absorptivity and Sandell's sensitivity of 3.92 x 10 4 dm 3 mor1 cm -1 and 0.0030 μg Sn cm -2 , respectively at 415 nm. The method is highly selective and free from the interference of a large number of elements including platinum metals. It is sensitive, simple, rapid and has been satisfactorily applied to the analysis of various synthetic and technical samples including gun metal.

Speciation of organotin compounds in waters and marine sediments using purge-and-trap capillary gas chromatography with atomic emission detection

A procedure for the simultaneous determination of six organotin compounds, including methyl-, butyl- and phenyltins, in waters and marine sediments is developed. The analytes were leached from the solid samples into an acetic acid:methanol mixture by using an ultrasonic probe. The organotins were derivatized with sodium tetraethylborate (NaBEt 4) in the aqueous phase, stripped by a flow of helium, pre-concentrated in a trap and thermally desorbed. This was followed by capillary gas chromatography with microwave-induced plasma atomic emission spectrometry as the detection system (GC–AED). Each chromatographic run took 22 min, including the purge time. Calibration curves were obtained by plotting peak area versus concentration and the correlation coefficients for linear calibration were at least 0.9991. Detection limits ranged from 11 to 50 ng Sn l −1 for tributyltin and tetramethyltin, respectively. The seawater samples analyzed contained variable concentrations of mono-, di- and tributyl- and monophenyltin, ranging from 0.05 to 0.48 μg Sn l −1, depending on the compound. Some of the sediments analyzed contained concentrations of dibutyl- and tributyltin of between 6.0 and 13.0 ng Sn g −1. Analysis of the certified reference material PACS-2, as well as of spiked water and sediment samples showed the accuracy of the method. The proposed method is selective and reproducible, and is considered suitable for monitoring organotin compounds in water and sediment samples.

TBT contamination identified in Antarctic marine sediments

We report for the first time butyltin contamination of near-shore sediments at six sites in the Ross Sea, Antarctica. A very high concentration of 2290 μg Sn kg −1 sediment was recorded in one sample. The most likely source is abrasion of antifouling paint from the hulls of ice-breakers, but this pattern of contamination is also possible following ship groundings. Antifoulant biocides, such as TBT, have not been considered or detected in Antarctica previously and represent a new challenge to environmental managers and custodians.

Fluorescence X-ray microscopy on hydrated tributyltin-clay mineral suspensions

Using the scanning transmission X-ray microscope at ID21 beamline of the ESRF in fluorescence mode, we mapped tin at a bulk concentration of 1000 μg(Sn)/ml within hydrated tributyltin (TBT) - clay mineral (Kaolinite) dispersion with sub-300 nm spatial resolution. Using the L absorption edges of tin at 3929, 4156 and 4465 eV fluorescence radiation was excited in tin atoms with incident photon energies of 4 and 4.5 keV. When using 4 keV radiation, only tin fluorescence is excited. For 4.5 keV X rays, both the fluorescence of tin and calcium (which is present in the solid phase) can be measured. Methodologically, we were interested in assessing and proving the possibilities and limitations of fluorescence mapping using the L absorption edges of tin, where the fluorescence yield is significantly lower compared to other elements with their K edges in the same energy range. Scientifically, organotin-clay mineral interactions are of environmental concern because this factor influences significantly the distribution of toxic TBT in the aquatic system. On one hand, the half-life of TBT deposited to the sediment phase increases, and consequently the time of its bioavailability. On the other hand, the adsorption process is reversible, which means that contaminated sediments can act as a source of pollution. The adsorption and desorption effects can be studied directly with high spatial resolution and brought into connection to the surface properties of the clay mineral under study as well as to other experimental parameters, like pH or salinity.

Organotin compounds in Mersey and Thames Estuaries a decade after UK TBT legislation

Organotin (OT) compounds were determined in surface sediments and mussels Mytilus edulis from two major estuaries of the UK, the Mersey and the Thames, approximately one decade after legislation banning the use of tributyltin (TBT) compounds on small boats. Tributyltin concentrations in Mersey sediments ranged from 0·007–0·173 μg (as Sn) g−1 dry wt, increasing from the most upstream site, Fiddlers Ferry, towards the middle section of the estuary, and were highest at Stanlow, perhaps indicative of sources from the Manchester Ship Canal (MSC). A further peak in TBT concentrations occurred at New Brighton, opposite Liverpool Docks. Tributyltin was the predominant butyltin (BT) species in sediments (approximately 50%). Despite the fact that BTs represented only 4% of the total (HNO3-extractable) tin in sediments there was a linear relationship between these two tin compartments. Furthermore, BTs in mussels were correlative with total extractable tin in sediment, though in contrast to sediments, 85% of the total tin in mussels was made up of BTs, the most predominant of which was TBT. Concentrations of TBT in mussels increased from 0·058 μg Sn g−1 dry wt at the mouth of the estuary to 0·214 μg Sn g−1 dry wt at their upstream limit, close to the entrance to the MSC (Eastham). Triphenyltin (TPT) compounds were detected in only one sediment sample (New Brighton, 0·359 μg Sn g−1 dry wt) and one mussel population (Egremont, 0·022 μg Sn g−1 dry wt). Tributyltin concentrations in sediments from the Thames Estuary were marginally lower (0·002–0·078 μg Sn g−1 dry wt) than those found in the Mersey: highest concentrations were present in the upper estuary and decreased seaward. Again BTs contributed only a small percentage (&lt;1% mean) towards the total tin loading in Thames sediments, but represented most of the tin burden (80%) in mussels. In contrast to sediments, TBT levels in mussels from the Thames Estuary were slightly higher than the Mersey (concentrations ranged from 0·100 μg Sn g−1 dry wt at the mouth to 0·302 μg Sn g−1 dry wt upstream) suggesting that TBT bioavailability is disproportionately higher in the Thames. Phenyltins were not detected in Thames samples.

Routes of TBT uptake in the clam Ruditapes decussatus. I. Water and sediments as vectors of TBT uptake

This study assesses the relative importance of water and sediments as vectors of TBT uptake in the sediment-dwelling suspension feeder, Ruditapes decussatus. Accumulation of TBT was determined in R. decussatus exposed for 60 days to moderately high but environmentally realistic levels of TBT in water (100 ng Snl −1) and sediments (0.8 μg Sn g −1 dw), separately or in combination, using constant-flow systems. The results indicate that this species accumulates TBT predominantly from water. Although some accumulation from sediments does occur, the processing of large amounts of water needed to sustain the filter-feeding habits of this species is a prime determinant of TBT uptake. The route of exposure is reflected in tissue distributions of TBT in R. decussatus. However, gills are the most important site for accumulation of TBT from water, irrespective of whether contaminated sediments are present or not.

Spectrophotometric determination of Sn(II) using palladium chloride in kits for 99mTc radiopharmaceuticals

A method of quantitating Sn(II) suitable for the analysis of kits for 99mTc radiopharmaceuticals, based on a spectrophotometric determination using the Pd(II)–Sn(II) complex (yellow species) is described. The absorbance of the complex is measured at 410 nm and Beer's law is obeyed up to 250 μg Sn (II) in the aqueous phase. Several radiopharmaceutical kits were analyzed for their Sn(II) content. The investigation indicates that the procedure is simple, rapid and accurate for quantitative estimation of Sn(II) in various 99mTc-labelling kits during development, manufacture and storage.