Search results for "quantitative"
showing 10 items of 2409 documents
Conservation of amino-acid chromatograms.
1951
IN filter-paper partition chromatography, the ninhydrin reaction has been used almost exclusively for the identification and quantitative assay of amino-acids. One of the chief disadvantages of the blue pigment formed in this reaction is its rapid fading on filter-paper chromatograms. This makes it difficult to construct permanent or semi-permanent reference maps from which not only the type of amino-acid, but also the approximate quantity of the unknown mixture, can be deduced.
ARYL-VINYLSULFONE—REAGENTIEN ZUM SCHUTZ UND NACHWEIS VON THIOLFUNKTIONEN
1983
Abstract Aryl vinyl sulfones selectively react with thiol groups to acid-stable compounds which easily are cleaved by mild bases to thiol compounds. Ester and amide groups are not attacked under these conditions. Therefore, these compounds are good protecting groups or labels in peptide chemistry. The following aryl vinyl sulfones were investigated: phenyl vinyl sulfone 1, p-carbethoxyphenyl vinyl sulfone 15 and the fluorescent 5-dimethylaminonaphthyl 1-vinyl sulfone 5 and 5-methoxynaphthyl-1 vinyl sulfone 10. The last two compounds are very useful reagents for the quantitative determination of SH-groups in polypeptides such as enzymes. Aryl-vinylsulfone reagieren selektiv mit Thiolgruppen …
Bestimmung von Tri-n-butylphosphat in Plasmapräparaten nach Festphasenextraktion und Kapillar-Gaschromatographie
1988
A simple method for the quantitative determination of tri-n-butylphosphate in blood plasma preparations is described. The sample is passed through an octadecyl extraction column from which tri-n-butylphosphate is eluted with chloroform. By capillary GC 50 micrograms/l tri-n-butylphosphate can be detected with a recovery of more than 90%.
Determination of Homovanillic Acid in Human Plasma Using HPLC with Electrochemical Detection and Automated Solid Phase Extraction
1993
Abstract An isocratic HPLC method with electrochemical detection for the quantification of homovanillic acid (HVA) is described. The method included automated solid phase extraction on C-18-reversed phase material, followed by separation on a 3-μm Nucleosil 100 C18 column (250 mm × 4.6 mm I. D.) with a 100 mM citric acid solution (pH 6.6) containing 4% acetonitrile (v/v) as eluent at a flow rate of 0.6 ml/min. Isovanillinic acid served as internal standard. Extractability of both analytes was ca. 80 %. After extraction of 1 ml of plasma, coefficients of variation of replicate analyses were below 10 % in the naturally occuring concentration range.
FIA-Fluorimetric assembly for the determination of noradrenaline hydrochloride by a solid-phase reactor with immobilized hexacyanoferrate(III)
1997
An FIA assembly provided with immobilized hexacyanoferrate(III) is proposed for the fluorimetric determination of noradrenaline hydrochloride. The oxidative reagent is immobilized by means of a strong anion-exchange resin. The FIA manifold is very simple and the calibration graph is linear over the range 0.5–75mgl−1 noradrenaline hydrochloride with an r.s.d of 0.88% (17 replicates) and a sample throughput of 84h−1. Foreign compounds such as NaCl, sucrose, lactose and sodium sulfate caused no significant errors. The procedure is applied to the determination of noradrenaline in a medicinal formulation.
Über die struktur eines räumlich gebauten, aus 2.4.6-Tri(hydroxymethyl)-phenol erhaltenen polykondensates
1960
Bei der Schmelzkondensation von 2.4.6-Tri(hydroxymethyl)-phenol entsteht ein raumlich gebautes Polykondensat, das uber Dimethylenatherbrucken verknupfte Phenolkerne enthalt. Dies kann durch die quantitative Bestimmung der bei der Polykondensation erhaltenen Abspaltungsprodukte gezeigt werden; ferner durch die Bromanalyse der Hydrolyseprodukte aus der quantitativ verfolgten Hydrolyse der Polykondensate mit gasformigem HBr. Setzt man die ublichen Atomabstande und Bindungswinkel in Rechung, so sollten in dem raumlich gebauten Netzwerk Dreikern-, Vierkern-, Funfkern-, Sechskern- und hohere Kernringe vorkommen konnen. Ein Beispiel hierfur ist die Vierkernringverbindung mit der Konstitution IIIβ.…
Hydrolysis of Phytic Acid by Microwave Treatment: Application to Phytic Acid Analysis in Pharmaceutical Preparations
1998
Abstract The acid hydrolysis of phytic acid in a Teflon reactor using a domestic microwave oven has been studied and compared with other reported procedures. In 0.44 M HCl quantitative hydrolysis was achieved with six heating stages of 2 min each. A lower yield was obtained with H 2 SO 4 and HNO 3 . The analytical use of this hydrolysis to determine phytic acid by indirect determination of phosphate has been demonstrated by analysis of three pharmaceutical formulations. No sample pretreatment other than obtaining a homogeneous suspension was necessary.
Application of Molecular Topology to the Prediction of the Reaction Yield and Anticancer Activity of Imidazole and Guanidine Derivatives
2013
In this study molecular topology based QSAR has been applied to predict the reaction yield and anticancer activity of 18 imidazole and guanidine derivatives. Four properties were evaluated, namely reaction yield, anti prostatic-cancer activity, anti breast-cancer activity and anti lung-cancer activity. The four models have been validated by both internal and cross validation, and also by randomness tests. The results obtained are in full agreement with the experimental results and confirm the precision, accuracy and robustness of the method followed. After carrying out a virtual screening upon such models, new imidazole and guanidine derivatives with potential anticancer activity are propos…
Infrared bandshapes of intramolecularly H-bonded systems, 2,4,6-tribromophenol
1983
Abstract A detailed quantitative analysis of the IR bandshape of the ν S (OH) vibration of 2,4,6-tribromophenol in a series of solvents of varying polarity is presented. A distinct dependence of band parameters on solvent polarity has been found. Various contributions to the bandshape are discussed.
Protein Quantitation: Bradford Method
2002
Protein quantitation according to the Bradford method. Keywords: protein quantitation; bradford; coomassie brilliant blue; calorimetric quantification