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A.S. Meyer

Bio: A.S. Meyer is an academic researcher. The author has contributed to research in topics: Isopropyl & Solubility. The author has an hindex of 2, co-authored 2 publications receiving 225 citations.

Papers
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Journal ArticleDOI
TL;DR: The use of xylene rather than chloroform to extract the nickel(II)-4- isopropyl- l,2-cyclohexanedionedioxime chelate results in increased sensitivity in the spectrophotometrie determination of nickel.
Abstract: The use of xylene rather than chloroform to extract the nickel(II)-4- isopropyl- l,2-cyclohexanedionedioxime chelate results in increased sensitivity in the spectrophotometrie determination of nickel. The extraction coefficient in xylene is more than five times as great as that in chloroform, and the low solubility of xylene in aqueous solution permits the use of much larger phase ratios (aqueous to organic). The system eonforms to Beer's law for concentrations of nickel from 1 to 12 of nickel per ml. of xylene. The precision of the method is 2%. Iron, cobalt, and copper interfere seriously; however, their interference can be minimized so that weight ratios of metal to nickel of 20, 2, and 8, respectively, can be tolerated. Concentrations of nickel from 0.005 to l00 ppm were determined in water, alkali metals, and several analytical reagents. Recoveries in excess of 95% were obtained when known amounts of nickel were extracted from aqueous solutions of relatively high ionic strength at aqueous-to-organic volume ratios as high as 300 to 1. (auth)

19 citations


Cited by
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Journal ArticleDOI
TL;DR: Transient free-radicals are produced in peroxidizing lipid-protein reaction systems and the pattern of damage to proteins, induced by these radicals, is similar to that observed in the case of radiation damage.

211 citations

Journal ArticleDOI
TL;DR: Amino acid separation with six different solvents on chromatoplates prepared from Kieselgel G (Merck) is described in this article, which is equal or superior to paper chromatography.
Abstract: Amino acid separation with 6 different solvents on chromatoplates prepared from Kieselgel G (‘Merck’) is described. As demonstrated in Figur 8 and discussed in the text, this technique is equal or superior to paper chromatography.

184 citations

Journal ArticleDOI
TL;DR: It is concluded that alli inase and alkyl cysteine sulphoxides are prevented from acting in the intact protoplast by compartmentation of the alliinase in the vacuoles andAlkyl Cysteine Suloxides in the cytoplasm.

151 citations

Journal ArticleDOI
TL;DR: For example, the authors showed that β-glucans in barley endosperm cell walls exist as polymers of very high molecular weight (about 4 × 107 daltons) containing firmly linked peptide sequences.
Abstract: β-Glucans in barley endosperm cell walls exist as polymers of very high molecular weight (about 4 × 107 daltons) containing firmly linked peptide sequences. This peptidic material is an essential part of the structure of the β-glucan complex as it exists in the cell wall. Rupture of peptide bonds by hydrazinolysis or with the proteolytic enzyme thermolysin gives β-glucans similar in size to those from short-grown green malts (about 106 daltons). This suggests that proteolysis is the first step in β-glucan degradation. Large β-glucans are not all precipitated in 30% (w/v) ammonium sulphate; only 34% of the β-glucan in a hot aqueous extract of cell walls is precipitated. The amount is increased to 63% if the cell walls have been previously dehydrated. Prolonged incubation of cell wall β-glucan at 40°C, mechanical stress, chromatography lasting 8–10 h at or above 65°C, or chromatography in M sodium chloride causes some disassociation of high molecular weight β-glucan to a size of about 107 daltons. Heating a solution for 1 h at 100°C does not disassociate the β-glucan. Pentosans isolated from cell walls are not covalently linked to the β-glucans and can be separated from them by molecular sieve chromatography. They have a higher xylose/arabinose ratio than previously reported for barley pentosans. The pentosan molecules extracted by water are smaller (106 daltons) than those extracted by alkali (5 × 106 daltons). Little difference was observed in the chemical or physical properties of cell wall materials of barley cultivars of different malting qualities.

150 citations

Book ChapterDOI
01 Jan 1965
TL;DR: The authors showed that free amino acids and peptides are markedly hydrophilic compounds, only slightly soluble in nonaqueous solvents, and this must be borne in mind when sampling and preparing materials for TLC as well as when choosing the solvent.
Abstract: Free amino acids and peptides are markedly hydrophilic compounds, only slightly soluble in non-aqueous solvents. This must be borne in mind when sampling and preparing materials for TLC as well as when choosing the solvent. Some data on solubilities of a few amino acids in various solvents which illustrate this are:

143 citations