Evaluation of digestion methods for analysis of trace metals in mammalian tissues and NIST 1577c (original) (raw)
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The evaluation of biologically important trace metals in liver, kidney and breast tissue
Applied Radiation and Isotopes, 2009
The levels of iron (Fe), copper (Cu), zinc (Zn) and potassium (K) have been measured in normal and malignant liver and kidney tissue using X-ray fluorescence. Zn was reduced in liver and kidney tumours by 63% and 26%, respectively. Fe, Cu and K were increased in kidney tumours by 150%, 8% and 90%, and reduced in liver tumours by 76%, 29% and 43%. A synchrotron microprobe was used to map calcium (Ca), Fe, Cu and Zn in breast tissue. The distributions were compared to reference images and higher concentrations of metals correlated with areas of cancer cells. The average increase of Ca, Fe, Cu and Zn concentrations in areas of malignancy were 70%, 43%, 53% and 87%.
Analytical and Bioanalytical Chemistry, 1996
Two microwave digestion systems (openfocused and closed-pressurized) were tested for the mineralization of human brain and bovine liver (NIST SRM 1577a) as dissolution steps prior to the determination of 16 trace elements (Bi, Cd, Co, Cs, Cu, Fe, Hg, Mn, Mo, Pb, Rb, Sb, Sn, Sr, Tl, and Zn) by inductively coupled plasma mass spectrometry (ICP-MS). Digestion parameters (mass of sample, digestion mixture, and power/time steps) were optimized using temperature and pressure sensors. Digestions with the open-focused microwave system require larger volumes of conc. HNO and 30% H O than digestions with the closed-pressurized system. Both systems produce correct results for the bovine liver samples. The concentrations obtained for the digests of the open-focused system tend to be less precise than the concentrations from the ''closed-pressurized'' digests. Because the ''open-focused'' digests must be diluted to 50 mL to bring the acid concentration to 0.7-2.0 mol/L required by the ICP-MS (closed-pressurized digests need to be diluted to only 20 mL), the detection limits for the system with the open-focused digestion are higher than for the system with the closed-pressurized digestor. The open-focused digestor cannot handle more than 150 mg brain tissue, whereas the closed-pressurized system can mineralize 470 mg. The latter method gave better results with brain tissue than the open-focused system. The preparation of brain tissue as reference material for the determination of trace elements in brain samples is described.
Mikrochimica Acta, 1995
The efficiency of four methods of digestion was evaluated for trace metal analysis of pork meat and carp fish tissues. Two methods of dry and two methods of wet ashing were compared in terms of calculated variances. Mixtures ofHC1 + HNO 3 were applied for wet ashing of the samples at 100 ~ while dry ashing with or without H2SO 4 at 450 ~ were the alternative methods. The digests were subsequently analysed for Pb, Cd, Cu and Zn by graphite furnace atomic absorption spectrometry. Analysis of variance and Student's t-test were performed separately for meat and fish analytical results. Wet digestion with a (1 + 1) mixture ofHC1 + HNO 3 has given better recovery and repeatability for almost all metals than a (9 + 1) mixture of HC1 + HNO 3. Also between the dry ashing methods, the use of H2SO 4 has given better results than ashing of the tissues without HzSO 4.
World journal of gastroenterology : WJG, 2007
To assess whether trace metal concentrations (which influence metabolism as both essential and non-essential elements) are increased or decreased in cancerous tissues and to understand the precise role of these metals in carcinogenesis. Concentrations of trace metals including Cd, Ni, Cu, Zn, Fe, Mg and Ca in both cancerous and non-cancerous stomach tissue samples were determined by atomic absorption spectrometry (AAS). Tissue samples were digested using microwave energy. Slotted tube atom trap was used to improve the sensitivity of copper and cadmium in flame AAS determinations. From the obtained data in this study, the concentrations of nickel, copper and iron in the cancerous human stomach were found to be significantly higher than those in the non-cancerous tissues, by using t-test for the paired samples. Furthermore, the average calcium concentrations in the cancerous stomach tissue samples were found to be significantly lower than those in the non-cancerous stomach tissue samp...
Influence of ashing techniques on the analysis of trace elements in animal tissue : I. Wet ashing
Biological trace element research, 1981
A multitude of methods exists at present for the solubilization of biological tissues for atomic absorption analysis. We have examined several common methods of wet ashing using NBS bovine liver in order to determine which acids, acid combinations, or bases should be used as digesting agents for accurate and precise measurement of iron, copper, zinc, and manganese. Nitric acid proved to be the most effective wet ashing agent. With nitric acid, mean concentrations for iron, copper, and zinc differed from NBS certified values by less than 1.5% while those for manganese differed by 4%.
PubMed, 2015
Background: Microwave is the most reliable sample digestion method. However, it requires expensive microwave digester automation and has relatively low productivity. In this study, three non-automated digestion methods, i.e. wet acid digestion using nitric acid (HNO3) and hydrogen peroxide (H2O2), wet acid digestion using HNO3, and dry washing, are compared in order to determine the best approach. Methods: Certified reference material IAEA-086 (International Atomic Energy Agency, Austria) and hair and nail samples from 20 female students of Universiti Kebangsaan Malaysia, aged 19 to 30 years, were collected and analysed using the three digestion methods. Results: For hair samples, analysis of variance of repeated measures showed significant differences in the level of all elements (P < 0.001) between the three methods. For nail samples, only the copper (Cu) level showed no significant difference (P = 0.100) between methods. Wet acid digestion using HNO3 and H2O2 showed the best within- and between-run relative standard deviation (RSD) values, with within-run RSD for all elements, except for selenium (Se), < 5%. The between-run precision ranges from 6.14% to 17.96% for hair and from 3.53% to 11.52% for nail samples. Wet acid digestion using HNO3 and H2O2 showed both good accuracy and precision for manganese (Mn) and magnesium (Mg), with percentage recoveries of 110% and 96.9%, respectively. All elements show higher method detection limit (MDL) values than the previous study: 0.05 μg/g Mg for wet acid digestion using HNO3, 0.02 μg/g Se for wet acid digestion using HNO3 and H2O2, and 0.2 μg/g Mg for dry ash method. Conclusion: Wet acid digestion using HNO3 and H2O2 proved to be the best method in terms of precision, accuracy, recovery, and MDL. However, only Mn and Mg showed adequate precision, accuracy, and percentage of recovery.
Microchemical Journal, 1998
Disorders of essential elements arise from inadequate intake, genetic defects, excessive exposure, or impaired elimination. Severe deficiency is rare, but aspecific symptoms and reduced protection against risk factors have been ascribed to suboptimal intake of trace elements. Inherited disturbances of the metabolism of copper, zinc, and molybdenum determine severe diseases, which may have fatal outcomes. Besides occupational and environmental exposure, metal toxicity has been reported in clinical conditions such as parenteral nutrition and hemodialysis. The prevention, diagnosis, and monitoring of pathological conditions related to trace elements, as well as pharmacokinetic studies of metallodrugs and therapy monitoring, rely mainly on the dosage of metals in appropriate compartments, such as blood, urine, and tissues (hair, nails, biopsies, and postmortem samples). However, appropriate compartments may not always be amenable for sampling, and determination of the total amount of an element may not be informative or may even be misleading if the compartment volume also undergoes changes or the different chemical forms of the element vary in opposite directions. New biochemical tests may become available for the prevention, diagnosis, and monitoring of disorders of trace elements as analytical techniques gain improved detection and resolution power. In particular, interest is focused on the dosage of biologically active elemental species and the application of stable isotopes in tracer studies.