scispace - formally typeset
Search or ask a question

Showing papers on "Reagent published in 1981"


Journal ArticleDOI
TL;DR: Four colorimetric procedures suitable for the determination of peptidase activity on peptides having a free α- or e-amino group are described, and various peptides and amino acid derivatives except for the glycylpeptides give only a faint color with these methods.

428 citations


Journal ArticleDOI
TL;DR: Potassium hydrogen persulfate in aqueous methanol was found to be a convenient, inexpensive, and chemoselective reagent for the oxidation of sulfides to sulfones and sulfoxides in the presence of other common functional groups as mentioned in this paper.

383 citations


Patent
Yamashita Katsuji1, Hiroshi Umetsu1, Hirotaka Sato1, Yoshio Matsuoka1, Kei Kida1 
09 Nov 1981
TL;DR: In this article, an automatic chemical analyzer suitable for chemically analyzing a number of analysis items is disclosed, where samples in sample containers are sequentially dispensed to an array of reaction vessels using a first pipetting tube.
Abstract: An automatic chemical analyzer suitable for chemically analyzing a number of analysis items is disclosed. Samples in sample containers are sequentially dispensed to an array of reaction vessels using a first pipetting tube. Reagent solutions selected in accordance with the analysis items are fed to the reaction vessels using a second conductive pipetting tube. The reaction solutions in the reaction vessels are measured by a photometer. When the reagent solutions are sucked into the second pipetting tube, the liquid levels of the reagent solutions in the reagent containers are detected by a liquid level sensor formed by the second pipetting tube and a conductive electrode. The amounts of the reagent solutions remaining in the reagent containers are determined based on the position of the liquid level sensor and the numbers of times of dispense allowed to the reagent solutions with respect to the analysis items are displayed on a cathode ray tube.

327 citations


Journal ArticleDOI
TL;DR: A complete analysis of rat brain phospholipids by the above methods agrees closely with that obtained by other procedures.
Abstract: 1. Quantitative O-deacylation of phospholipids has been achieved by incubation with a reagent containing monomethylamine, methanol and water. The reaction is primarily an O leads to N-transacylation with N-methyl fatty acid amides being formed. 2. The reagent can be removed easily by volatilization and under defined conditions no secondary decomposition of the phosphorus-containing deacylation products occurs. 3. The water-soluble phosphorus compounds derived by deacylation of mammalian tissue O-diacylated phospholipids have been completely separated by a single-dimensional paper ionophoresis with a volatile pH9 buffer. 4. The O-deacylated alkyl and alkenyl phospholipids have been examined by t.l.c. before and after catalytic hydrolysis with Hg2+. 5. A complete analysis of rat brain phospholipids by the above methods agrees closely with that obtained by other procedures.

273 citations


Journal ArticleDOI
TL;DR: The fluorigenic reaction of proline with 7-fluoro-4-nitrobenzo-2-oxa-l,3-diazole (NBD-F) is superior, in terms of reactivity and fluorescence yield, to the reactions with the analogous 7-chloro and 7-bromo derivatives as mentioned in this paper.

191 citations


Journal ArticleDOI
TL;DR: In this paper, the coupling of 1-naphthol with diazotised sulphanilic acid produces by competitive, consecutive reactions two dyestuffs, whose concentrations can readily be measured spectrophotometrically.

188 citations


Journal ArticleDOI
TL;DR: Benzyl trichloroacetimidate reacts with hydroxyl-groups under acid catalysis to give the corresponding benzyl etehrs in good yield; acid-labile protecting groups such as acetals are able to survive the reaction conditions.
Abstract: Benzyl trichloroacetimidate reacts with hydroxyl-groups under acid catalysis to give the corresponding benzyl etehrs in good yield; acid-labile protecting groups such as acetals are able to survive the reaction conditions.

169 citations


Patent
22 Jun 1981
TL;DR: In this paper, a process for carrying out a specific binding assay (for example an immunoassay) is described, in which a sample under assay, possibly containing a substance being tested for, is reacted with a specific bounding partner for the substance, immobilised on a solid support, and conjugated to a detectable marker.
Abstract: A process for carrying out a specific binding assay (for example an immunoassay) in which (a) a sample under assay, possibly containing a substance being tested for, is reacted with (b) a specific binding partner for the substance being tested for, immobilised on a solid support, and (c) a specific binding partner for the substance being tested for which is conjugated to a detectable marker, thereby to form a complex by reaction between whatever quantities are present of the substance being tested for with reagents (b) and (c), in which the marker is immobilised to the support via the substance being tested for, and is detected or assayed as an index of the quantity present in the sample (a) of any of the substance being tested for; characterised in that reaction ingredients (a), (b) and (c) are all mixed in a single step for reaction in a single reaction liquid, and competitive interference between the binding reactions of the substance being tested for and reagents (b) and (c) is avoided either by use of an antibody of narrow and different, non-interfering specificity, such as a monoclonal antibody, to avoid the interference, or by use of a slow-release form of reagent (c).

146 citations


Journal ArticleDOI
TL;DR: In this article, a modified pararosaniline colorimetric method for more precise determination of formaldehyde in aqueous solution is described, and the optimization of reagent concentrations, the effect of varying temperature, and potentially interfering compounds are reported.
Abstract: A modified pararosaniline colorimetric method for more precise determination of formaldehyde in aqueous solution is described. Unlike earlier methods, the use of hazardous mercury reagent is not required. The optimization of reagent concentrations, the effect of varying temperature, and potentially interfering compounds are reported. Comparative data on the analysis of aqueous formaldehyde solutions shows that the modified pararosaniline method is more sensitive, more reproducible, and easier to use than the widely accepted chromotropic acid method. The slopes of the calibration lines are 0.533 AU mL ..mu..g/sup -1/ (absorbance units per (microgram per milliliter)) for the pararosaniline and 0.233 AU mL ..mu..g/sup -1/ for chromotropic acid. Both methods were used to determine indoor formaldehyde levels in two energy-efficient homes, and the findings are compared.

139 citations


Journal ArticleDOI
TL;DR: The identity of various esters fo cholanic acids formed using this reagent have been checked by gas chromatography-mass spectrometry and various other procedures used for the methylation of fatty acids have been examined to establish whether they can beused for the quantitative esterification of bile acids.

111 citations


Book ChapterDOI
TL;DR: In this article, the selective introduction of substituents into carbohydrates and the hydrolysis, acetolysis, and isomerization of polyacetals is discussed, and it is shown that the acid-catalyzed isomerisation of carbohydrate acetals occurs with favored cleavage of only one of the two acetal carbon-to-oxygen bonds.
Abstract: Publisher Summary This chapter discusses the selective introduction of substituents into carbohydrates and the hydrolysis, acetolysis, and isomerization of acetals. Of all the selective, deprotection procedures that are available to carbohydrate chemists, the partial hydrolysis of polyacetals is probably the most familiar. The acetolysis reagent trifluoroacetic- anhydride-acetic acid shows specificity similar to that of the acetic anhydride-acetic acid-sulfuric acid reagent; however, it offers the important advantage of obtaining acetatehydroxy derivatives under mild conditions because of the greater hydrolytic liability of the O-(trifluoroacetoxymethyl) group compared to the O-acetyl group. Solely on the basis of product structure, the acid-catalyzed isomerization of carbohydrate acetals occurs with favored cleavage of only one of the two acetal carbon-to-oxygen bonds. Enzymic hydrolysis can often provide the means for solving a problem involving the partial hydrolysis of esters. Relatively little work has been reported on the sequential removal of phosphate groups by chemical means from compounds containing several such groups.

Journal ArticleDOI
TL;DR: Fourier transform infrared spectroscopy has been used to characterize the oxidation of a coking coal and the results demonstrate that the most important initial products of oxidation are carbonyl and carboxylic acid groups.
Abstract: Fourier transform infrared spectroscopy has been used to characterize the oxidation of a coking coal. The results demonstrate that the most important initial products of oxidation are carbonyl and carboxylic acid groups. Bands associated with carbon-oxygen single bonds, as in ethers or phenols, do not become prominent until the later stages of the oxidative process. Upon reaction with potassium in tetrahydrofuran a number of changes in the spectrum of both the oxidized and unoxidized coal become apparent. This reagent cannot be considered specific for cleavage of ether bonds, but can also lead to products usually associated with air oxidation.

Patent
15 Apr 1981
TL;DR: An automatic chemical analyzer for measuring quantitatively a plurality of kinds of substances of a number of sample liquids comprises: a reagent delivery unit including a pluralityof reagent bottles containing different kinds of reagents which are required for measuring the plurality of kind of substances and a syringe type dispenser for delivering given amounts of Reagents into a set of empty reaction vessels set in a cassette, a reaction vessel supply unit for holding the cassettes and for supplying successively the reaction vessels in which given reagents have been previously delivered in accordance with given test items to be performed RE
Abstract: An automatic chemical analyzer for measuring quantitatively a plurality of kinds of substances of a number of sample liquids comprises: a reagent delivery unit including a plurality of reagent bottles containing different kinds of reagents which are required for measuring the plurality of kinds of substances and a syringe type dispenser for delivering given amounts of reagents into a plurality of empty reaction vessels set in a cassette, a reaction vessel supply unit for holding a plurality of cassettes and for supplying successively the reaction vessels in which given reagents have been previously delivered in accordance with given test items to be performed, an analyzing unit for receiving the successive reaction vessels from the reaction vessel supply unit and including a syringe type sample delivery pump for supplying given amounts of sample liquids into the reaction vessels and a colorimetric device for measuring colorimetrically test liquids in the reaction vessels, a first control unit for controlling the operation of the reagent delivery unit and a second control unit for controlling the operation of the reaction vessel supply unit in accordance with a given program. In the reagent delivery unit, the reagents are delivered into the reaction vessels in accordance with a program which can be previously determined statistically.

Journal ArticleDOI
TL;DR: In this paper, N-Benzyloxycarbonyl amino-protecting group (Z) was removed by using HBr-AcOH, which was then removed by removing the benzyloxy carbonyl peptide group by HBrAcOH.


Patent
07 Aug 1981
TL;DR: In this paper, a multilayer analytical element for detecting a ligand in or the ligand binding capacity of a liquid sample of the type having a reagent layer(s) incorporating reagents which are responsive to ligand detection, a radiation reflecting layer, and a support layer was proposed.
Abstract: A multilayer analytical element for detecting a ligand in or the ligand binding capacity of a liquid sample of the type having a reagent layer(s) incorporating reagents which are responsive to the ligand in or the ligand binding capacity of the sample to give a detectable response, a radiation reflecting layer, and a support layer, the improvement wherein the reagent layer(s) is a radiation diffusing layer and the radiation reflecting layer is a radiation nondiffusing reflecting layer which is (a) interposed between the reagent layer(s) and the support layer; (b) impermeable to the ligand, reagents of the reagent layer(s), and products of their interreaction; and (c) inert to the ligand, reagents of the reagent layer(s), and products of their interreaction.

Journal ArticleDOI
TL;DR: In this paper, disubstituted olefins react with isobutylmagnesium halide in the presence of a catalytic amount of Cp 2 TiCl 2 in ether to afford E-alkenyl Grignard reagents in almost quantitative yields.

Journal ArticleDOI
TL;DR: The product produced by the action of o-iodosobenzoic acid upon tryptophanyl bonds has been identified as N-acyldioxindolylalanine, and it is inferred from that structure that the chemical reaction proceeds via a two-step oxidation of the tryPTophanyl residue followed by formation of an iminospirolactone which hydrolyzes, cleaving the peptide chain.
Abstract: o-Iodoxybenzoic acid, a disproportionation product of o-iodosobenzoic acid, has been identified as a contaminant in most preparations of o-iodosobenzoic acid capable of both modifying and cleaving certain tyrosyl residues. A new synthetic approach for the production of o-iodosobenzoic acid containing low amounts of o-iodoxybenzoic acid combined with preincubation of the reagent with p-cresol to destroy the remaining o-iodoxybenzoic acid prior to the reaction with a polypeptide allows preparation of reagent solutions in which tyrosyl residues remain intact during tryptophanyl bond cleavage. In addition, the product produced by the action of o-iodosobenzoic acid upon tryptophanyl bonds has been identified as N-acyldioxindolylalanine. It is inferred from that structure that the chemical reaction proceeds via a two-step oxidation of the tryptophanyl residue followed by formation of an iminospirolactone which hydrolyzes, cleaving the peptide chain. Small peptides ending with dioxindolylalanine can be coupled to aminopropyl glass in high yield and are suitable for solid-phase Edman degradation.


Journal ArticleDOI
TL;DR: In this paper, aldehydes were added to 1-acylethenyl anion equivalent to give aldol adducts in fair to good yields, and Diethylaluminium iodide was found to be an efficient reagent for the same type transformation.
Abstract: Organoaluminium reagents R2AlX (X=SPh, SeMe) easily add to α,β-unsaturated carbonyl compounds in 1,4-fashion. The resulting aluminium enolates react with aldehydes to give aldol adducts in fair to good yields. Formal elimination of HX from the adducts provides α-substituted α,β-unsaturated carbonyl compounds. The overall transformation is an addition of aldehydes to 1-acylethenyl anion equivalent. Diethylaluminium iodide also is found to be an efficient reagent for the same type transformation.

Journal ArticleDOI
TL;DR: Dianisyl telluroxide (1) has been shown to be an especially mild and selective oxidising reagent for a number of organic substrates as discussed by the authors, and can be transformed to their oxo analogues either directly by 1 or by a catalytic cycle involving the use of 1,2-dibromotetrachloroethane as a room temperature brominating agent for various Te11 species.



Patent
09 Jun 1981
TL;DR: In this paper, a process for the preparation of 4,1,6'-trichloro-4, 1, 6'-trideoxygalactosucrose (TGS) comprising the steps of reacting sucrose with an acylating reagent under conditions to provide a mixture of acylated sucrose derivatives containing a major proportion of 6-monoacylated material was described.
Abstract: A process for the preparation of 4,1',6'-trichloro-4,1',6'-trideoxygalactosucrose (TGS) comprising the steps of: (a) reacting sucrose with an acylating reagent under conditions to provide a mixture of acylated sucrose derivatives containing a major proportion of 6-monoacylated material; (b) optionally separating 6-monoacylated sucrose derivative from other acylated derivatives before step (c); (c) reacting the monoacylated sucrose derivative with a chlorinating reagent capable of chlorinating at positions 1', 4 and 6' of a sucrose 6- acylate; and (d) deacylating and separating (in either order) the 4,1',6'-trichloro-4,1',6'-trideoxygalactosucrose material formed.


Patent
11 Mar 1981
TL;DR: In this paper, a discrete type automated chemical analytic apparatus, where a carrier member is compatible with a reaction line constituted by those of the reaction tubes linearly arranged on an endless belt supported by two reagent-pipetting nozzles in a vertically movable state, is described.
Abstract: A discrete type automated chemical analytic apparatus, wherein a carrier member reciprocatable in parallel with a reaction line constituted by those of the reaction tubes linearly arranged on an endless belt which are set on the top run of the endless belt supports two reagent-pipetting nozzles in a vertically movable state. The corresponding reagent containers are disposed on an extension of the reaction line. The nozzles through which the reagent is sucked from the reagent containers pipette the sucked reagent into the corresponding reaction tubes at predetermined points on the reaction line in accordance with the movement of the carrier member. The specimen discharge mechanism includes a nozzle for pipetting a specimen at a prescribed point on the reaction line.

Journal ArticleDOI
TL;DR: In this article, the influence of the alignment of the laser excited Ca(1P1) reagent on the chemiluminescent reaction Ca(A2∏,B2Σ+) + H is discussed.
Abstract: The influence of the alignment of the laser‐excited Ca(1P1) reagent on the chemiluminescent reaction Ca(1P1)+ HCl→CaCl(A2∏,B2Σ+) + H is discussed. (AIP)

Patent
30 Nov 1981
TL;DR: An immunochemical method and reagent compounds for determining ligands in a sample are presented in this paper. But their method is limited to the detection of specific ligands and does not consider the identification of specific antibody specific to the ligand.
Abstract: An immunochemical method and reagent compounds for determining ligands in a sample. The reagent compounds are derivatives of a triazinylaminofluorescein and are represented by the structural formula ##STR1## wherein Y is halo or lower alkyl; and R is a ligand-analog wherein said ligand-analog has at least one common epitope with said ligand so as to be specifically recognizable by a common antibody. The reagent compound and an antibody specific to the ligand are added to the sample in a fluorescence polarization immunoassay.


Journal ArticleDOI
TL;DR: In this article, a detailed fragmentation mechanism for protonated arenes is proposed and the effective proton affinity of the methane-derived reagent system is estimated to be ∼556 kJ mol−1.
Abstract: The H2, N2/H2, CO2/H2, N2O/H2, CO/H2 and CH4 chemical ionization mass spectra of thirteen C8 to C11 alkylbenzenes are reported. Characteristic hydride and alkide ion abstraction reactions are observed with all reagent gases. The major fragmentation reactions of [MH]+ are olefin elimination to form a protonated arene and arene elimination to form an alkyl ion. From the effect of structure and protonation exothermicity it is concluded that rearrangement of primary alkyl groups to the more stable secondary or tertiary structure occurs prior to alkyl ion formation. A detailed fragmentation mechanism for protonated arenes is proposed. The ‘effective’ proton affinity of the methane-derived reagent system is estimated to be ∼556 kJ mol−1.