Particle size distribution in ground biological samples

Koglin, D.; Backhaus, F.; Schladot, J. D.

doi:10.1016/s0045-6535(97)00066-0

Cited by 35 publications

(20 citation statements)

References 2 publications

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“…O congelamento rápido gera falhas na estrutura cristalina dos materiais tornando-os mais quebradiços, facilitando a moagem 21 . Por ocorrer na temperatura de liquefação do nitrogênio (-196 o C) o risco de eventuais perdas de compostos por volatilização é inexistente.…”

Section: Resultados Preparo Das Amostrasunclassified

Preparação de amostra de fígado bovino e estudo de micro homogeneidade para a determinação de Cd E Pb por espectrometria de absorção atômica com atomização eletrotérmica e amostragem direta de sólido

Nomura

Oliveira

2006

Quím. Nova

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Recebido em 27/1/05; aceito em 3/8/05; publicado na web em 20/1/06 BOVINE LIVER SAMPLE PREPARATION AND MICRO-HOMOGENEITY STUDY FOR Cd AND Pb DETERMINATION BY SOLID SAMPLING ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY. This work describes a systematic study for bovine liver sample preparation for Cd and Pb determination by solid sampling electrothermal atomic absorption spectrometry. Samples were prepared using different procedures: (1) drying in a household microwave oven followed by drying in a stove at 60 o C until constant mass, and (2) freeze-drying. Ball and cryogenic mills were used for grinding. Particle size, sample size and micro sample homogeneity were investigated. All prepared samples showed good homogeneity (H e < 10) even for low sample mass, but samples dried in a microwave oven/stove and ground in a ball mill presented the best homogeneity.Keywords: solid sampling atomic absorption; homogeneity; bovine liver INTRODUÇÃO A determinação de elementos em nível de traços em amostras biológicas como fluídos 1,2 , tecidos 3 e órgãos 4 é importante porque gera informações que auxiliam na resolução de problemas relacionados a estudos nutricionais, toxicológicos e bioquí-micos. Em certos casos, a necessidade de informações sobre a ocorrência, distribuição e forma química de elementos nos materiais biológicos tem incentivado o desenvolvimento de procedimentos analíticos visando, além da determinação total, a especiação química 5 . Uma das técnicas mais recomendadas para determinação de elementos traços em materiais biológicos é a espectrometria de absorção atômica com atomização eletrotérmica (ETAAS). As altas seletividade e sensibilidade, simplicidade nas operações e automação promovidas pelo amostrador automático, o que dispensa a atenção constante do analista, são características importantes que merecem destaque. Na maioria dos métodos, a preparação da amostra envolve apenas diluição em um solvente adequado e introdução direta no tubo de grafite.

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Section: Resultados Preparo Das Amostrasunclassified

Preparação de amostra de fígado bovino e estudo de micro homogeneidade para a determinação de Cd E Pb por espectrometria de absorção atômica com atomização eletrotérmica e amostragem direta de sólido

Nomura

Oliveira

2006

Quím. Nova

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“…In order to ensure a high degree of continuity, all steps of the ESB sample treatment are performed according to ESB standard operation procedures [50,55,56]. Herring gull eggs are collected annually from the North Sea islands Trischen and Mellum and from the Baltic Sea island Heuwiese (Figure 1).…”

Section: Esb Sample Treatmentmentioning

confidence: 99%

Levels and trends of industrial chemicals (PCBs, PFCs, PBDEs) in archived herring gull eggs from German coastal regions

et al. 2012

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Background: Polychlorinated biphenyls [PCBs], perfluorinated compounds, and polybrominated diphenyl ethers [PBDEs] were retrospectively analyzed in archived herring gull (Larus argentatus) eggs from the North and the Baltic Sea over the last 20 years. The aim was to assess temporal trends and effects of regulatory measures. Results: PCBs (sum of 7 congeners) were highest in eggs from the North Sea island Trischen, i.e., 3,710 to 20,760 ng/g lipid weight [lw] compared to 2,530 to 11,650 ng/g lw on the North Sea island Mellum and 4,840 to 9,190 ng/g lw on the Baltic Sea island Heuwiese. During the study period, PCBs decreased significantly. Concentrations of PFOS ranged between 46 and 170 ng/g wet weight [ww] at Trischen, 39 to 99 ng/g ww at Mellum, and 20 to 159 ng/g ww at Heuwiese. Since 2000 and 2003, concentration levels decreased in eggs from Mellum and Heuwiese, respectively. Perfluorooctanoic acid was the dominant perfluorinated carboxylic acid in the North Sea eggs (Trischen 2.0 to 74 ng/g ww; Mellum 2.6 to 118 ng/g ww), whereas perfluoroundecanoate [PFUnA] and perfluorodecanoate [PFDA] (means 3.9 ± 3.6 ng/g and 2.9 ± 2.3 ng/g ww, respectively) dominated in the Baltic Sea eggs. At all three locations, longerchained perfluorinated carboxylic acids (perfluorononanoate, PFDA, PFUnA, perfluorododecanoate) increased during the monitoring period. PBDE concentrations (sum of 35 congeners) in eggs were in the ranges of 282 to 2,059 ng/g lw (Mellum), 116 to 1,722 ng/g (Trischen), and 232 to 2,021 ng/g lw (Heuwiese). Congeners associated with commercial Penta-and Octa-BDE formulations decreased during the study period. No decrease was observed for technical Deca-BDE. Conclusion: Effects of regulatory measures were apparent for PCBs and Penta-and Octa-BDE, while no consistent trend is noticeable for PFOS.

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“…The vessels were then cooled in liquid nitrogen for a few minutes and vibrated for 1 min at 3000 cycles min -1 . The cryogenic grinding relies on the increase of hardness of all tissues, the insertion of failures into the (crystal) structure, and the use of very smooth brittle forces for the size reduction [11]. The technique was applied to the evaluation of the distribution pattern of the bulk and trace elements (K, P, Cl, Na, Fe, Zn, Rb, Mn, Se, Co, and Ag) in those liver samples, and the measurements were performed by instrumental neutron activation analysis.…”

Section: Introductionmentioning

confidence: 99%

Determination of Cd and Pb in food slurries by GFAAS using cryogenic grinding for sample preparation

Santos¹,

Barbosa²,

Tomazelli³

et al. 2002

Anal Bioanal Chem

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A simple method combining slurry sampling after cryogenic grinding and the use of a permanent modification of the integrated platform inside the transversely heated graphite atomizer (THGA) was proposed for the determination of Cd and Pb in foods. Potentialities of the cryogenic grinding were evaluated for grinding different materials of difficult homogenization such as high fat and high fiber tissues. Animal and vegetal samples were cut into small pieces and ground in liquid nitrogen for 2 min. Slurries were prepared directly in the autosampler cup after cryogenic grinding by transferring an exact amount of homogeneous powdered material (5-20 mg) to the cup, followed by 1.00 mL of 0.2% (v/v) HNO3 containing 0.04% (v/v) Triton X-100 and sonication for 30 s, before transferring into the platform previously coated with 250 microg W and 200 microg Rh. Use of a tungsten carbide-rhodium permanent modifier combined with NH4H2PO4 conventional modifier improves tube lifetime and increases the pyrolysis temperature for Cd. Homogeneity tests, carried out by comparing the between- and within-batch precision for each kind of sample, showed no significant differences at the 95% confidence level, indicating good homogeneity for 5-20 mg masses. Detection limits were 3.3 ng g(-1) Cd and 75 ng g(-1) Pb for 1% m/v slurries. Results for determination of Cd and Pb in foods slurries were in agreement with those obtained with digested samples, since no statistical differences were found by the paired t-test at the 95% level.

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Particle size distribution in ground biological samples

Cited by 35 publications

References 2 publications

Preparação de amostra de fígado bovino e estudo de micro homogeneidade para a determinação de Cd E Pb por espectrometria de absorção atômica com atomização eletrotérmica e amostragem direta de sólido

Preparação de amostra de fígado bovino e estudo de micro homogeneidade para a determinação de Cd E Pb por espectrometria de absorção atômica com atomização eletrotérmica e amostragem direta de sólido

Levels and trends of industrial chemicals (PCBs, PFCs, PBDEs) in archived herring gull eggs from German coastal regions

Determination of Cd and Pb in food slurries by GFAAS using cryogenic grinding for sample preparation

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