Determination of lead in foodstuffs and biological samples by hydride generation atomic absorption spectrometry using an aqueous slurry technique

Madrid, Yolanda; Bonilla, Milagros; Cámara, Carmen

doi:10.1039/ja9890400167

Cited by 31 publications

(10 citation statements)

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“…Moreover, larger samples required the addition to the slurry of higher volumes of Triton X-100, and sample sizes below 0.7 g were not representative of the real sample and yielded inaccurate values in Pb and Cd determinations. The addition of a thixotropic thickening agent is necessary to produce a suspension that remains stable for several days and that can be sampled reproducibly (Madrid et al, 1989). In our experiments, Triton X-100 was used as a dispersing agent.…”

Section: Resultsmentioning

confidence: 99%

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Lead and Cadmium Contamination in Dairy Products and Its Repercussion on Total Dietary Intake

Cabrera¹,

Lorenzo²,

López³

1995

J. Agric. Food Chem.

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An accurate and precise method is described for the direct determination of lead and cadmium in dairy products, using slurried samples in combination with electrothermal atomic absorption spectrometry. The samples are suspended in Triton X-100 and shaken with 10.0 g of zirconia spheres until a slurry is formed. The slurry preparation procedure and the graphite furnace conditions were optimized for both elements. The results obtained were validated against microwave acid sample digestion. The detection limit was 0.4 pg for Pb and 0.5 pg for Cd. The analytical application of this method was tested with 60 samples of 10 widely consumed dairy products. The mean values ranged from not detectable to 0.750 pg/g for Pb and from not detectable to 20.0 ng/g for Cd. Increased concentrations of lead and cadmium were detected in products packaged in glazed ceramic containers. Metal migration from the container was also tested. Because milk and dairy products are some of the most widely consumed foods in the human diet, they contribute a large fraction of the intake of trace elements. Strict control of trace element levels in these foods is therefore advisable.

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Section: Resultsmentioning

confidence: 99%

“…A few drops of 30% (v/v) silicone antifoaming emulsion in water was added before slurry dilution with deionized Milli-Q water. This grinding procedure ensured that 90% of the particles had a diameter of less than 25 pm (Madrid et al, 1989). This particle size was small enough to determine Pb and Cd by…”

Section: Methodsmentioning

confidence: 99%

Lead and Cadmium Contamination in Dairy Products and Its Repercussion on Total Dietary Intake

Cabrera¹,

Lorenzo²,

López³

1995

J. Agric. Food Chem.

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“…As has been reported in the literature, an improved limit of detection for lead by hydride generation and atomic spectroscopic detection can be obtained by including an auxiliary oxidizing agent such as persulphate [5,7,12]. The dashed line in Fig.…”

Section: Resultsmentioning

confidence: 87%

“…The method has been applied to the determination of lead, but difficulties due to low efficiency of the plumbane generation have been reported [2]. However, this could be improved by addition of an oxidizing agent and a number of reagent systems have been proposed [3][4][5][6][7][8][9]. A recent review by Madrid and Ca´mara gives an overview of the topic [10].…”

Section: Introductionmentioning

confidence: 99%

Flow-injection determination of lead by hydride generation and conductometric detection

Hauser

Zhang

1996

Analytical and Bioanalytical Chemistry

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Plumbane produced from the lead analyte in a flow-injection manifold by reaction with sodium borohydride is passed through a porous poly(tetrafluoroethylene) membrane in a gas-diffusion cell. The hydride reacts with bromine in the acceptor stream resulting in ionization which is detected by conductivity measurement. Direct mixing of the carrier with a reagent stream yields a limit of detection of approximately 1 mg/L. An improved detection limit of about 200 microg/L can be achieved by the incorporation of an auxiliary stream containing persulphate as oxidizing agent. The application of the method to the determination of lead in road dust and soil samples is demonstrated.

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“…A variety of sample pre-treatment procedures and additives [12][13][14][15][16][17][18] have been described and evaluated for the production of quasi-stable suspensions of samples prior to analysis by atomic spectrometry. Alternatively, suspensions with a tendency to segment rapidly have been reproducibly sampled by using ultrasonic agitation, 19 air or argon 20 bubbling, vortex mixing 21 or magnetic stirring.…”

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confidence: 99%

Enzymic Digestion–High-pressure Homogenization Prior to Slurry Introduction Electrothermal Atomic Absorption Spectrometry for the Determination of Selenium in Plant and Animal Tissues

Tan¹,

Marshall²

1997

Analyst

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Homogenization, in combination with partial enzymic digestion with a crude protease alone or admixed with lipase or cellulase, was investigated as a means of releasing Se residues from zoological and botanical matrices prior to slurry introduction ETAAS. Preliminary timed trials with two zoological certified reference materials (CRMs), one botanical CRM and one animal feed indicated that Se release became quantitative with 4-8 h of digestion, that homogenization prior to digestion increased the initial rate of analyte release, but that homogenization post-digestion and immediately prior to ETAAS did not significantly improve the precision of replicate digestions. Storage of the crude botanical digests at 4 °C for 5 d resulted in quantitative recoveries of Se from each of the digests. Storage at 4 °C for 10 d of 4 and 8 h lipase/protease digests of six other CRMs resulted in quantitative recoveries of Se unless their certified concentrations were appreciably less than the levels determined in control digests containing the enzyme(s) alone. Apparently, Se residues were transferred virtually quantitatively to the liquid phase of the digested suspension and showed no tendency to segregate during the 10 d of storage. Eight other mixtures of ground plant matter (0.13 @ [Se] @ 1.31 mg g 21 ), formulated as animal feed supplements, behaved identically when stored post-digestion. The technique was also applied successfully to freeze-dried fresh and boiled fish tissues The principal advantages of the enzymic digestion procedure are its simplicity and lack of operator intervention.

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Determination of lead in foodstuffs and biological samples by hydride generation atomic absorption spectrometry using an aqueous slurry technique

Cited by 31 publications

References 0 publications

Lead and Cadmium Contamination in Dairy Products and Its Repercussion on Total Dietary Intake

Lead and Cadmium Contamination in Dairy Products and Its Repercussion on Total Dietary Intake

Flow-injection determination of lead by hydride generation and conductometric detection

Enzymic Digestion–High-pressure Homogenization Prior to Slurry Introduction Electrothermal Atomic Absorption Spectrometry for the Determination of Selenium in Plant and Animal Tissues

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