Hydride Generation Atomic Absorption Spectrometer Research Articles

Air-assisted solidified floating organic drop microextraction method based on green supramolecular solvent for arsenic and selenium qantification in water and food samples

A supramolecular solvent (SUPRAS) was prepared from undecanoic acid and tetrabutylammonium hydroxide and used as an extraction solvent. A fast microextraction approach based on air-assisted solidified floating organic drop (AA-SFODME) coupled to a hydride generation atomic absorption spectrometer (HG-AAS) for arsenic and selenium traces determination in water and food samples was developed. The air bubbles enhanced the extraction efficiency by reducing both the time and the required chemical amounts. The 2-((4-iodophenyl) diazenyl)-8-hydroxyquinoline (IPHQ) was used as a chelation reagent. The experimental factors that impact extraction efficiency were improved and optimized. The limits of detection (LODs) for arsenic and selenium were 0.09 and 0.07 µg L−1, respectively. Also, the preconcentration factors (PFs) and enhancement factors (EFs) were found to be 100 and 103 for both arsenic and selenium, respectively. The linearity of both two calibration curves ranged from 0.10 to 700 µg L−1, with linear regression coefficients (R2) of 0.9986 and 0.9978, respectively. Finally, the greenness score was determined using two tools: the analytical greenness calculator (AGREE) and the Blue Applicability Grade Index (BAGI). The high greenness scores from these tools can make this method even more environmentally friendly and practical.

Validation of an analytical method for the determination of inorganic, organic, and total arsenic in fish sauce based on hydride generation atomic absorption spectrometry

An atomic absorption spectrometric (AAS) method was performed to determine the total, inorganic, and organic arsenic in fish sauce. The total organic arsenic was calculated from the total and inorganic arsenic values quantified using the hydride generation AAS (HG-AAS). Under optimal experimental conditions at the absorbance wavelength of 193.7 nm, the concentration of inorganic arsenic in fish sauce ranged from 0.05 to 1.2 mg/L, with a limit of detection (LOD) of 0.015 mg/L. The detectable total arsenic concentrations varied widely, ranging from 0.03 to 2.5 mg/L with the LOD of as low as 0.01 mg/L. The practical applicability of the method was demonstrated with the recovery in the range from 97 to 102% for inorganic arsenic, and 97 to 101% for organic arsenic. The method was applied to the analysis of commercial products from Nha Trang, Phan Thiet, and Phu Quoc City, Vietnam. The total organic arsenic in fish sauce samples determined by HG-AAS was compared with the results of liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP/MS). The f-test and t-test showed null hypothesis for acceptable variance and mean at a confidence level of 95%. The results showed that the HG-AAS method had high efficiency, accuracy, and sensitivity in quantifying inorganic and total organic arsenic in fish sauce using simple instrumentation.

Arsenic Contamination in Water from Selected Boreholes in Nairobi City County, Kenya

Arsenic is a metalloid, which may be found in surface water, ground water, plants and rocks. In high concentrations, its compounds are considered to be genotoxic and carcinogenic. Its levels in drinking water must be regularly monitored and controlled. The objective of study was to determine the concentration of arsenic in water with reference to WHO limits from selected boreholes in Nairobi County, Kenya. Water was randomly sampled from a total of 63 boreholes in five zones (Central, Eastern, Northern, Western and Southern) during dry and wet season. The arsenic was analyzed by Hydride Generation Atomic Absorption Spectrometer (HG-AAS). The results showed that the arsenic content in borehole water during dry season ranged between 0.00455±0.0022 and 0.01007±0.006 and in the range of 0.002057±0.0008 - 0.00744±0.0051 mg/L during the wet season. There was significant difference (P˂0.05) in arsenic content in borehole water samples in Central zone compared to the other zones. During the dry season, arsenic content in water from ten boreholes (16%) and four boreholes (6%) during wet season was found to be above the WHO recommended limit of 0.01 mg/L. The calculated contamination factor for the borehole water ranged from slightly arsenic contaminated in Central zone to very slightly contaminated in the other zones during dry season. During the wet season, the borehole water in all the five zones were very slightly contaminated with arsenic. The pollution index showed that the boreholes in all the five zones during both wet and dry seasons were not polluted with arsenic. Steps should be taken to monitor and treat borehole water for domestic purposes in order to mitigate the effect on human health due to arsenic contamination.

Selenium content in Bg 350 variety of rice consumed by Sri Lankans

Selenium is considered as an essential micronutrient. The daily requirement of selenium is 55 µg. As a result, the World Health Organization (WHO) has drawn their attention to establish the micronutrient range of selenium, required by the human body. Report from China has shown that an ecological correlation exists with the selenium content in the soil and increased mortality due to cancer and cardiovascular diseases with light intake of selenium. This led to the interest in assessing the nutritional status of selenium. Rice is the staple food of Sri Lankans and studies on selenium content in rice grown in Sri Lanka have not been reported. The present study reports the selenium content in Bg 350 variety of rice and soil obtained from twelve districts (Gampaha, Colombo, Matara, Hambantota, Kegalle, Matale, Anuradhapura, Pollanaruwa, Kurunegalle, Puttalam, Ampara and Moneragalle), in Sri Lanka determined using Hydride Generation Atomic Absorption spectrometer (HGAAS). The results of the study showed that selenium content in rice and soil obtained from Gampaha and Colombo districts were very low and less than the detectable levels of the instrument (0.5 μg/kg). Except for rice and soil from Pollanaruwa district that had a very high selenium content in rice (61.2 μg/kg) and soil (69.8 μg/kg), the respective values from other districts were low [13.8 μg/kg (Kegalle) -6.3 μg/kg (Anuradhapura)] and [20.3 μg/kg (Matara) -9.5 μg/kg (Matale)].

Selenium content in meals consumed for lunch by Sri Lankans and the effect of cooking on selenium content

The selenium (Se) content in meals consumed by Sri Lankans for lunch, composed of fixed and random menus, was determined using Hydride Generation Atomic Absorption Spectrometer. The samples were obtained from five districts in Sri Lanka. The Se content (μg/kg) in meals of fixed and random menus was in the range of 48-70 and 53-60 respectively. These values are comparable to the daily requirement of Se (55 μg/kg) prescribed by the World Health Organization and Food and Agriculture Organization of the United Nations. There is no significant difference in Se content in meals consumed by people in the districts of Kandy, Gampaha, Kurunegala, Rathnapura, and Colombo, as well as among individual households in each district. The effects of different cooking methods on the Se content indicate that the level of Se (μg/kg) in fried chicken (30.45 - 52.49) is less than that in a chicken curry (61.38 - 84.25). The percentage loss of Se during cooking for chicken, dahl ( Lens culinaris ) and Gotukola ( Centella asiatica ) were 89.6%, 84.1%, and 79.9% respectively. The present study revealed that Se content in Sri Lankan menus provides the required Se for people. However, the different methods of cooking indicate that there is a loss of Se during cooking.

Serum Selenium Concentration and Subsequent Risk of Diabetes Miletus in Pakistan

Background: The purpose of the study was to explore a relationship between serum Selenium level and diabetes. Methods: Analysis of 100 blood samples were carried out, collected from Institute of Medical Sciences (PIMS), Islamabad, Pakistan. All the subjects selected were local inhabitants of Rawalpindi and Islamabad and their serum selenium levels were measured by hydride generation atomic absorption spectrometer. Results: Analysis of the mean serum selenium level in the male and female patients of both type I and II were 169 ± 91 μg/L and 199.25 ± 120 μg/L respectively while mean serum selenium level among males and females of healthy subjects was 245.59 ± 131 μg/L and 239.92 ± 138. Conclusion: Serum Selenium level and Diabetes has an inverse relation.

Reliability of graphite furnace atomic absorption spectrometry as alternative method for trace analysis of arsenic in natural medicinal products

Purpose: To evaluate the comparative efficiency of graphite furnace atomic absorption spectrometry (GFAAS) and hydride generation atomic absorption spectrometry (HGAAS) for trace analysis of arsenic (As) in natural herbal products (NHPs). Method: Arsenic analysis in natural herbal products and standard reference material was conducted using atomic absorption spectrometry (AAS), namely, hydride generation ASSAAS (HGAAS) and graphite furnace (GFAAS). The samples were digested with HNO 3 –H 2 O 2 in a ratio of 4:1 using microwave-assisted acid digestion. The methods were validated with the aid of the standard reference material 1515 Apple Leaves (SRM) from NIST Results: Mean recovery of three different samples of NHPs, using HGAAS and GFAAS, ranged from 89.3 - 91.4 %, and 91.7 - 93.0 %, respectively. The difference between the two methods was insignificant. A ( P = 0.5), B ( P =0.4) and C ( P =0.88) Relative standard deviation (RSD) RSD, i.e., precision was 2.5 - 6.5 % and 2.3 - 6.7 % using HGAAS and GFAAS techniques, respectively. Recovery of arsenic in SRM was 98 and 102 % by GFAAS and HGAAS, respectively. Conclusion: GFAAS demonstrates acceptable levels of precision and accuracy. Both techniques possess comparable accuracy and repeatability. Thus, the two methods are recommended as an alternative approach for trace analysis of arsenic in natural herbal products. Keywords: Arsenic, Graphite furnace atomic absorption spectrometer (GFAAS), Hydride generation atomic absorption spectrometer (HGAAS), Natural herbal products

Arsenic Speciation of Waters from the Aegean Region, Turkey by Hydride Generation: Atomic Absorption Spectrometry.

Arsenic in drinking water is a serious problem for human health. Since the toxicity of arsenic species As(III) and As(V) is different, it is important to determine the concentrations separately. Therefore, it is necessary to develop an accurate and sensitive method for the speciation of arsenic. It was intended with this work to determine the concentrations of arsenic species in water samples collected from Izmir, Manisa and nearby areas. A batch type hydride generation atomic absorption spectrometer was used. As(V) gave no signal under the optimal measurement conditions of As(III). A certified reference drinking water was analyzed by the method and the results showed excellent agreement with the reported values. The procedure was applied to 34 water samples. Eleven tap water, two spring water, 19 artesian well water and two thermal water samples were analyzed under the optimal conditions.

Arsenic groundwater contamination and its health effects in Patna district (capital of Bihar) in the middle Ganga plain, India

We investigated the extent and severity of groundwater arsenic (As) contamination in five blocks in Patna district, Bihar, India along with As in biological samples and its health effects such as dermatological, neurological and obstetric outcome in some villages. We collected 1365 hand tube-well water samples and analyzed for As by the flow injection hydride generation atomic absorption spectrometer (FI-HG-AAS). We found 61% and 44% of the tube-wells had As above 10 and 50 μg/l, respectively, with maximum concentration of 1466 μg/l. Our medical team examined 712 villagers and registered 69 (9.7%) with arsenical skin lesions. Arsenical skin lesions were also observed in 9 children of 312 screened. We analyzed 176 biological samples (hair, nail and urine). Out of these, 69 people had arsenical skin lesions and rest without skin lesions. We found 100% of the biological samples had As above the normal levels (concentrations of As in hair, nail and urine of unexposed individuals usually ranges from 20 to 200 μg/kg, 20–500 μg/kg and <100 μg/l, respectively), indicating many people are sub-clinically affected. Arsenical neuropathy was observed in 40.5% of 37 arsenicosis patients with 73.3% prevalence for predominant sensory neuropathy and 26.7% for sensor-motor. Among patients, different clinical and electrophysiological neurological features and abnormal quantitative sensory perception thresholds were also noted. The study also found that As exposed women with severe skin lesions had adversely affected their pregnancies. People including children in the affected areas are in danger. To combat As situation in affected areas, villagers urgently need (a) provision of As-safe water for drinking and cooking, (b) awareness about the danger of As toxicity, and (c) nutritious food.

Fluoride and arsenic exposure through water and grain crops in Nagarparkar, Pakistan

The aim of present study was to simultaneously estimate the arsenic (As) and fluoride (F−) concentrations in irrigated surface water, soil and grain crops of Nagarparkar, Pakistan during 2010–2012. The As and F− were analyzed by hydride generation atomic absorption spectrometer and ion selective electrode, respectively. Total arsenic (AsT) and F− in irrigated surface water samples were found in the range of 360–683μgL−1 and 18.5–35.4mgL−1, respectively. While AsT and F− concentrations in agriculture soil samples were observed in the range of 110–266 and 125–566mgkg−1, respectively. The water extractable As and F− were found 3–4% of total concentration of these in soils.The AsT concentration was higher in kidney been (KB) as compared to pearl millet (PM) and green gram (GG), whereas GG had higher F− levels as compared to other two grain crops (p<0.05). The KB samples grown in nine sites shows BCF of As in the range of 0.018–0.038. The GG has higher BCF of F− as compared to KB and PM (p<0.05) grown in all sites. The exposure dose and risk factor of As and F− were obtained by estimated daily intake (EDI) and hazardous index (HI). It was found that all understudy age groups were at the severe risk of arsenicosis and fluorosis, but the severity is higher in younger age group (7–15years) as compared to elder groups (p<0.05).

Assessment of arsenic levels in Guguletu and Langa rivers in Cape Town, South Africa

This study investigates the baseline environmental levels of arsenic (As) in two rivers; one of which traverses through Guguletu (R1) and the other running by the peripheral of Langa (R2) residential areas in Cape Town. The rivers were monitored for As in upstream, midstream and downstream stations for twelve months, during consecutive summer and winter seasons between 2011 and 2012. The collected water samples were treated with HCl and KI, and heated in a water bath at 80°C for 30 min, and As was measured using hydride generation atomic absorption spectrometer (HG-AAS). The data obtained were subjected to descriptive statistics, while the Duncan Multiple Range tests was used to compare the mean concentrations of As in the different sampling stations, and between the two rivers. The mean concentration levels of arsenic ranged R1, 0.98±0.34 to 1.23±0.43 (0.62 – 2.03) µg/L and 0.43±0.02 to 0.44±0.03 (0.08 – 0.68) µg/â„“. The highest concentration of As (2.03 µg/â„“) was observed in R1 river water during summer, and the least concentration 0.08 µg/â„“ in R2 water during winter. There was significant difference (P≤0.05) in the mean concentrations of As in R1 and R2 rivers water, while the seasonal mean concentrations during winter and summer, was not significantly different (P≥0.05). The concentrations of As detected in both rivers were lower than the recommended guideline value for freshwater. Key words: Arsenic, concentration levels, seasonal, Guguletu and Langa rivers, Cape Town.

Determination of As(III) and total inorganic As in water samples using an on-line solid phase extraction and flow injection hydride generation atomic absorption spectrometry

A simple and robust on-line sequential injection system based on solid phase extraction (SPE) coupled to a flow injection hydride generation atomic absorption spectrometer (FI-HGAAS) with a heated quartz tube atomizer (QTA) was developed and optimized for the determination of As(III) in groundwater without any kind of sample pretreatment. The method was based on the selective retention of inorganic As(V) that was carried out by passing the filtered original sample through a cartridge containing a chloride-form strong anion exchanger. Thus the most toxic form, inorganic As(III), was determined fast and directly by AsH 3 generation using 3.5 mol L −1 HCl as carrier solution and 0.35% (m/v) NaBH 4 in 0.025% NaOH as the reductant. Since the uptake of As(V) should be interfered by several anions of natural occurrence in waters, the effect of Cl −, SO 4 2−, NO 3 −, HPO 4 2−, HCO 3 − on retention was evaluated and discussed. The total soluble inorganic arsenic concentration was determined on aliquots of filtered samples acidified with concentrated HCl and pre-reduced with 5% KI–5% C 6H 8O 6 solution. The concentration of As(V) was calculated by difference between the total soluble inorganic arsenic and As(III) concentrations. Detection limits (LODs) of 0.5 μg L −1 and 0.6 μg L −1 for As(III) and inorganic total As, respectively, were obtained for a 500 μL sample volume. The obtained limits of detection allowed testing the water quality according to the national and international regulations. The analytical recovery for water samples spiked with As(III) ranged between 98% and 106%. The sampling throughput for As(III) determination was 60 samples h −1. The device for groundwater sampling was especially designed for the authors. Metallic components were avoided and the contact between the sample and the atmospheric oxygen was carried to a minimum. On-field arsenic species separation was performed through the employ of a serial connection of membrane filters and anion-exchange cartridges. Advantages derived from this approach were evaluated. HPLC–ICPMS was employed to study the consistency of the analytical results.

Determination of Selenium (IV) in Natural Waters by HG‐AAS Using an Integrated Reaction Chamber Gas–Liquid Separator

A simple online sequential insertion manifold coupled to a hydride generation atomic absorption spectrometer (HG‐AAS) has been developed for selective inorganic Se(IV) determination. The online method is based on the sequential insertion of sample and reagents in the integrated reaction chamber gas–liquid separator (RC‐GLS), which operates initially as reaction chamber for various sample volumes (up to 20 mL) and subsequently as gas–liquid separator with limited dead volume. The generated hydride from a large sample volume is trapped in the RC‐GLS for a short time and then it is flashed in the atomic absorption cell. The HCl and the NaBH4 concentration was optimized for selective inorganic Se(IV) determination. For 8‐mL and 16‐mL sample consumption, the sampling frequency is 40 h−1 and 24 h−1, while the detection limit is 0.04 µg L−1 and 0.03 µg L−1, respectively. The precision (relative standard deviation) for 2.0 µg L−1 Se(IV) (n=10) is 2.6% and 2.8% for 8 mL and 16 mL sample volumes, respectively. The accuracy of the proposed method was evaluated by analyzing the certified reference material, NIST CRM 1643d, and also by analyzing spiked natural water. The authors were invited to contribute this paper to a special issue of the journal entitled “Spectroscopy and Automation”. This special issue was organized by Miguel de la Guardia, Professor of Analytical Chemistry at Valencia University, Spain.

Quantitation of Toxic Arsenic Species and Arsenobetaine in Pacific Oysters Using an Off-line Process with Hydride Generation−Atomic Absorption Spectroscopy

An off-line process-based speciation technique was devised here to quantitatively determine toxic inorganic arsenic (iAs), methylarsonic acid (MA), dimethylarsinic acid (DMA), and the dominant, albeit virtually nontoxic, arsenobetaine (AB) in Pacific oysters (Crassostrea gigas). Oysters were extracted with fresh methanol-water (8+2), and this was replicated three times. They were then evaporated to near dryness and subsequently redissolved in pure water; defatting was then performed with a C18 cartridge. The trace hydride active arsenic species, that is, iAs, MA, and DMA, in the defatted solutions were determined with a sensitive hydride generation-packed coldfinger trap-atomic absorption spectrometric (HG-PCFT-AAS) coupled system. The arsenicals that were desorbed from the cation-exchange resin (Dowex 50W-X8) in the washings of 4 M NH3 were categorized on the basis of AB + DMA. The total quantity of arsenic in the recovered AB + DMA was determined with a commercial hydride generation-atomic absorption spectrometric (HG-AAS) system, and finally, AB was calculated from (AB + DMA) - DMA. The average concentrations of iAs, MA, DMA, AB, and total arsenic (TAs) in the oysters collected from six aquacultural sites along the west coast of Taiwan were, respectively, 0.15, 0.06, 0.64, 6.93, and 13.74 mg kg(-1) of dry weight. AB was the major species, whereas iAs (arsenite + arsenate) were the most toxic species, although the iAs made up only approximately 1% of the TAs in the oysters. The lifetime target cancer risk, as determined by the concentration of iAs on a fresh weight basis in the oysters, was well below the ordinary health protection criteria (10(-6)).

Separation of trace antimony and arsenic prior to hydride generation atomic absorption spectrometric determination

A separation method utilizing a synthetic zeolite (mordenite) was developed in order to eliminate the gas phase interference of Sb(III) on As(III) during quartz furnace hydride generation atomic absorption spectrometric (HGAAS) determination. The efficiency of the proposed separation method in the reduction of suppression effects of transition metal ions on As(III) signal was also investigated. Among the volatile hydride-forming elements and their different oxidation states tested (Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), and Te(VI)), only Sb(III) was found to have a signal depression effect even at low (μg l −1) concentrations under the experimental conditions employed. It has been shown that mordenite adsorbs Sb(III) quantitatively, even at a concentration of 1000 μg l −1, at pHs greater than two, and also, it reduces the initial concentrations of the transition metal ions to lower levels which can be tolerated in many studies. The adsorption of Sb(III) on mordenite follows the Freundlich isotherm and is endothermic in nature.

Determination of selenium in infant foods using electrothermal atomic absorption spectrometry with direct slurry sample introduction

Abstract Slurry sampling electrothermal atomic absorption (SS ETAAS) was applied to the development of a sensitive and precise method for selenium determination in infant foods without sample pretreatment. Suspensions prepared in a medium containing 0.1% Triton X-100, 0.5 or 5% v/v concentrated HNO3 were directly introduced into the furnace. The accuracy of the procedure was confirmed by analysis of a standard reference material and comparison with hydride generation atomic absorption spectrometric (HGAAS) procedure. The characteristic mass is 44 pg and detection limit 0.43 μg·l−1.

Flow injection-hydride generation atomic absorption spectrometric determination of Se(VI) and Se(IV): utility of a conventionally heated water bath for the on-line reduction of Se(VI)

A simple flow injection manifold coupled to a hydride generation atomic absorption spectrometer has been designed for Se(VI) and Se(IV) determination. On-line reduction of Se(VI) is performed by passing the sample, in 6.8 M hydrochloric acid, through a conventionally heated water bath. Complete conversion into Se(IV) is achieved in about 1 min. Conventional on-line heating has proved to be a good alternative for the fast conversion of Se(VI) into Se(IV). Its performance, in comparison to microwave heating, is discussed. Reaction kinetic parameters have been obtained via on-line experiments for the first time. A comparison with those values already reported is also presented. A limit of detection of 0.05 ng ml −1 ( n=10, 3 s) is obtained for both forms, with a precision (relative standard deviation, n=10, 3 s) better than 3%. The sample throughput is 60 samples/h, better than other flow injection systems reported up to date.

Slurry sampling for hydride generation atomic absorption spectrometric determination of arsenic in cigarette tobaccos.

The development of a slurry sampling hydride generation atomic absorption spectrometric (HGAAS) method for the determination of arsenic in cigarette tobacco samples is described. The method is relatively simple and has been shown to give values of total arsenic close to those obtained using methods requiring total dissolution and decomposition of all vegetable matter before analysis. Pre-treatment of samples slurried in nitric acid by ultrasonication permitted the extraction of about 90% of the total arsenic from tobacco samples. Further improvement in the recovery efficiency (up to 93-94%) was accomplished by the use of an additional step of short microwave-accelerated treatment. L-Cysteine was used as a pre-reduction agent. The accuracy and precision of the slurry sampling HGAAS method were studied using the certified reference material (CRM) CTA-OTL-1 Oriental Tobacco Leaves. Under the optimum conditions, as little as 2.6 ng of arsenic can be detected. The relative standard deviation of the overall procedure was calculated to be below 7.6% at arsenic concentration levels of 0.5-0.9 mg kg-1 and the analytical results obtained for the CRM agreed with the certified value. The main factors that influenced the reliability of the method were sample homogeneity, particle size and slurry concentration.

Hydride generation atomic absorption spectrometric (HGAAS) determination of selenium in term and preterm infant formulae available in the United Kingdom

A simple and sensitive hydride generation atomic absorption spectrometry method is described for the determination of total selenium in infant formulae. Decomposition of the composite sample matrix involved overnight digestion with a nitric-perchloric acid mixture (10:2 ml) then heating at 150 °C (30 min) and 220 °C (60 min). No apparent matrix interferences were encountered. The selenium levels in infant formulae, reported for the first time, ranged from 0.034 to 0.093 μ/g (dry wt) for bovine casein and whey-based term powdered infant products, 0.023–0.093 μg/g (dry wt) for preterm powdered formulae and 0.027–0.049 μ/g (wet wt) for hospital administered low birth weight ready-to-feed formulae. These values are dependent on geographic origin of bovine milk and exhibit variation between batches. Routine QC analysis and fortification by manufacturers is recommended.

The determination of trace amounts of tin by flow-injection hydride generation atomic-absorption spectrometry with on-line ion-exchange separation and preconcentration

A hydride generation atomic-absorption spectrometric (AAS) method with flow-injection (FI), aimed at developing a practical routine assay for the determination of tin in food digests, is described. In order to modify the sample matrix and to achieve optimized and reproducible conditions for the hydride generation reaction, the analyte is initially converted into its chlorostannate-complex thereby allowing it to be separated and preconcentrated on-line on an incorporated micro-column packed with a strongly basic anion exchanger and subsequently to be eluted by diluted nitric acid under strictly controlled conditions. Optimum acidic conditions for the FI hydride generation AAS system was found to be 0.01–0.05 M nitric acid. At a consumption of 2.7-ml sample volume, aspirated by time-based injection, the procedure resulted in an enrichment factor of 3.5 and yielded a detection limit of 0.08 μg/l. (3σ) at a sampling frequency of 72/hr. The precision was 2.5% rsd at the 10 μg/l. level. Potential interferents, such as Ni(II), Co(II), Zn(II) and Fe(III) could, at a Sn level of 10 μg/l., be tolerated at an excess of 1000 times without impairing the assay, while a 100–1000-fold excess of Cu(II) decreased the signal by 10–15%. Recoveries in the range 94–102% were obtained for canned food sample digests spiked with 10 μg/l. Sn.