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Query: UMLS:C0205700 (ash)
 15,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A simple potentiometric method for the determination of fluoirde ion in human bones is described. The bone samples were taken from a definite position in the iliac crest. The samples are prepared for analysis by ashing at 550 degrees C, dissolving in HNO3 (4 mol/1) and adjusting the pH with NaOH (4 mol/1) and Total Ion Strength Adjustment Buffer, Absolute values are derived from a calibration curve based on aqueous NaF-buffer solutions. The calibration curve is linear in the range 5.2-10(-3)-1.0-10(-5) mol/1F-. The minimum limit of measurement is 5.2 X 10(-6) mol/1F-. The method has an accuracy of 96.1 % or 92.3% with a series precision based on the Pearson variability coefficient of 1.68%. The normal mass fraction of fluoride in human bones was found to be between 69 and 1740 - 10(-6) F-/ash.
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PMID:[Determination of fluoride in bone samples from human iliac crest with an ion-specific electrode (author's transl)]. 121 May 3

Vitamin B12 was determined in dry feeds by atomic absorption spectrophotometry (AAS). Samples containing B12 were extracted with an assay solution, 5 g EDTA was added to the filtrate, the pH was adjusted to 7 with NH4OH, and 5 g charcoal was added. The charcoal was removed by filtering through ashless paper which was then placed in a beaker and ashed at 600 degrees C. After dissolving the cobalt oxide from the ash in 5N HNO3, cobalt content was determined by using AAS. To determine mg B12/lb feed, ppm cobalt in the feed is multiplied by 10.43. The sensitivity of the proposed procedure is 1 mg vitamin B12/lb. The procedure is rapid and precise, and results compare favorably with AOAC method 43.109.
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PMID:Determination of vitamin B12 in dry feeds by atomic absorption spectrophotometry. 127 Mar 84

Aluminum, iron, tin, zinc, calcium, magnesium, nickel, copper, chromium, cadmium, and potassium in foods can be extracted by HCl-HNO3 leaching and determined quantitatively using flame atomic absorption spectroscopy (AAS), with recoveries ranging from 90 to 110%. Thirty to 40 samples of almost any type of food sample can be analyzed routinely for 2 elements in 4-5 h. In contrast, one or 2 days are required when a wet-ash or dry-ash technique is used. Extraction consists of weighing 2-10 g samples into 125 mL Erlenmeyer flasks, adding 20 mL concentrated HCl-HNO3 (9 + 1), then heating in a 82- 93 degrees C water bath for 30 min. After cooling, samples are diluted to volume in 50 mL Nessler tubes and then filtered through No. 541 or 540 Whatman paper. The filtrate is analyzed directly by AAS.
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PMID:Determination of trace elements in foods by HCl-HNO3 leaching and flame atomic absorption spectroscopy. 302 11

The TEM-EDS bulk-tissue analysis procedure described involves: (1) low-temperature oxygen-plasma ashing of soft tissue specimens weighing greater than 20 micrograms in aluminum-foil crucibles; (2) the solubilization of the ash in 5 microliter 0.5N HNO3 containing a known quantity of cobalt as an internal, non-interfering reference element; (3) the spraying of the solubilized ash from glass microcapillary tubes onto thin carbon-collodion films mounted on titanium grids; (4) EDS analysis of individual microdroplets approximately 3 micron in diameter; (5) the quantitation of elemental concentrations from the element: cobalt intensity ratio by the "ratio model" technique. This technique was assessed and found to yield linear curves (greater than or equal to 0.999) for elements in 'artificial tissue' standards (concentration range = 5 - 340 mM kg-1 dry weight). The overall reproducibility of the technique is therefore quite good (e.g. error of 4.7% for P and K in 25 analyses) within the range of concentrations expected for most of the major biological elements encountered in vertebrate and invertebrate soft tissues. Absolute accuracy can be improved with quantitative procedures that account for peak-overlapping and escape peak contributions etc., so that the ultimate MDL for sodium may well be of the order of 1 mM kg-1 dry weight. The usefulness of the technique for the provision of basic biochemical information (especially in invertebrate systems which have received but meagre attention) is illustrated: (a) by comparing the calcium content of male and female blood-flukes (Schistosoma mansoni) in mixed-sex and unisexual laboratory infections; and (b) by determining the changes induced by daily injections of the drug Astiban on the element composition of female Schistosoma. We conclude that the technique can represent a useful multi-element detection facility which offers certain pertinent advantages over alternative microchemical techniques, such as atomic absorption spectrophotometry.
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PMID:The electron microprobe analysis of sprayed microdroplets of solubilized biological tissues: a useful preliminary to localization studies. 663 80

Dry and wet ashing methods have been used in the analysis of garden vegetables for Pb. The reliability of wet ashing has been verified by the method of standard additions. Comparison of dry and wet ashing showed good agreement for a variety of garden vegetables. Sample size was more strictly limited for the wet-ashed samples, which led to lower sensitivity. Vegetable samples are commonly analyzed for a number of trace elements, which introduces additional constraints on sample preparation, notably because of Cd loss on dry ashing. Pretreatment with HNO3/H2SO4 ash aid eliminated Cd loss. Reliability of dry ashing with pretreatment was shown with NBS SRM Orchard Leaves, Pine Needles, Spinach, and Tomato Leaves. The analysis was insensitive to ashing temperature in the range 480-625 degrees C. A practical detection limit for the method is about 2 ppm Pb, dry weight basis (DWB). Care must be exercised to avoid contamination of the sample with lead at this level by improper handling. Segregation and acid washing of glassware and protection of the sample from contact with any object not demonstrably clean was necessary. No evidence was found of Pb contamination at this level from tap water washing of fresh vegetables, forced-air oven drying, or grinding with mortar and pestle. No special clean room facilities or laboratory air purification measures were used. Sensitivity was increased 3-fold by extraction with dithizone in CHCl3 followed by back-extraction into dilute HCl. Detection limits were not improved, however, because of variation in the extraction results. The instrumental method for assessing effective correction for back-ground absorbance showed adequate compensation, although comparison of direct and extractive determinations showed a small but significant difference between the methods of about 1 ppm Pb (DWB).
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PMID:Sample preparation in determination of lead in garden vegetables by flame atomic absorption spectrophotometry. 711 82

Analytical procedures are described for the determination of arsenic, cadmium, calcium, copper, lead, mercury, selenium, and zinc in animal feed. Mercury is determined by digesting the feed sample in a mixture of concentrated nitric and sulfuric acids with vanadium pentoxide added as an oxidation catalyst, reducing with stannous chloride, and sweeping the elemental mercury into an absorption tube for measurement by atomic absorption (AA) spectrophotometry. Arsenic and selenium are determined simultaneously by digesting the sample with a mixture of concentrated nitric, sulfuric, and perchloric acids; the hydrides of arsenic and selenium, which are formed with the addition of sodium borohydride, are swept into an argon-hydrogen flame for analysis by AA. A low temperature ash is prepared and dissolved in IN HNO3 for the analysis of calcium, copper, and zinc by emission spectroscopy using the inductively coupled argon plasma source; the same solution is used for the determination of cadmium and lead by flameless AA. Animal feed spiked with 3 levels of each of the 8 elements gave recoveries that ranged from 80 to 107%.
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PMID:Analysis of laboratory animal feed for toxic and essential elements by atomic absorption and inductively coupled argon plasma emission spectrometry. 730 50

A method for direct lead content analysis of milligram quantities of bone ash by flameless atomic absorption spectroscopy is described. Bone ash (25 mg) is dissolved with HNO3 and diluted with H2O and La2O3 (1,000 micrograms/ml) solution. Lanthanum ion is used to suppress matrix interferences possibly arising in part from sulfate components of the bone ash. Two bulk bone samples (about 14 and 60 micrograms Pb/g ash, respectively) were used to determine daily, within-day, and overall variability of the method. Values for "low lead" bone samples were 14.08 +/- 1.74 (SD) microgram Pb/g ash and for "high lead" bone samples were 60.85 +/- 5.24 (SD) microgram Pb/b ash. The overall value of 58 lead recovery determinations from bone ash analysis was 103.5% (+/- 12.9% SD). These values compare favorably with results previously reported using gram amounts of sample.
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PMID:Lead in bone. I. Direct analysis for lead in milligram quantities of bone ash by graphite furnace atomic absorption spectroscopy. 745 34

This study determines ash, K, Ca, Na, Mg, Fe, Cu, Pb, and Zn content in musts and wines of the DOC Tacoronte-Acentejo (Tenerife, Canary Islands) from two consecutive harvests. Samples were treated with HNO3 and H2O2. Na and K were determined by flame photometry and the remaining metals by air/acetilene flame atomic absorption spectrophotometry. Significant differences were observed in Na, Ca and Mg contents between both harvests, possibly due to climate conditions.
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PMID:Quantity of K, Ca, Na, Mg, Fe, Cu, Pb, Zn and ashes in DOC Tacoronte-Acentejo (Canary Islands, Spain) musts and wines. 900 77

Results of aluminium determinations obtained by employment of N2O-C2H2 flame AAS method and spectrophotometric oxine (SO) method in teas, fresh leaves of celery and some other food samples were compared. The samples were digested for few hours in teflon beakers with use of a mixture of concentrated acids (H2SO4 + HNO3 + HCIO4), and then transported for final destruction into platinum dishes for ashing. The obtained stock sample solutions were used for examination by both methods. The accuracy was checked with recovery test of aluminium added to the samples before decomposition. With employment of AAS-method 83.3% to 100% (mean 94.2 +/- 8.1%) of added aluminium was recovered, and in the SO method from 86.4 to 109.3% (mean 98.6 +/- 5.2%). Great care is necessary for preparation of the blank. Food products containing higher levels of aluminium (i.e. teas and herbs) can be determined directly by the employed AAS-method using 1-2 g of samples for decomposition, while foods containing low levels of aluminium need use of larger samples for decomposition (i.e. 5-10 g or even more than 50 g in the case of strawberry or fresh leaves of celery) and the obtained ash should be dissolved to as low as possible of final volume of stock sample solution. The SO method is about 7 to 10 times more sensitive than the nitrous-oxide flame AAS method and enable to determined about 2.5 micrograms of Al per sample in form of oxine complex extracted into a 5 ml chloroformic phase. In the case of AAS-method the lowest determined level of aluminium amounted about 6 micrograms/ml of the examined sample solution. The results of both methods are strong correlated, as it is showed by the correlation coefficient (r = 0.97) at the level of significance alpha = 0.05.
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PMID:Aluminium determination in foods by using spectrophotometric oxine and flame AAS methods. 963 73

Two methods of extracting mineral elements from otherwise deadlock products of a life-support system are presented. We describe first optimum conditions for recovering elements by water extraction from dry wastes of plants, biomass ash, and solid human wastes after passing them through the catalytic furnace; and, second, we describe acid extracts of biogenous elements by 1N and 2N HNO3 from these products. Ways to use the extracts of elements in plant nutrition are considered in order to increase the extent to which the mineral loop of a life-support system can be closed.
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PMID:Extraction of mineral elements from inedible wastes of biological components of a life-support system and their utilization for plant nutrition. 1153 19


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