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Results for “POLAROGRAPHY”

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At least 307 records · Page 17Linked to original sources
PubMed1990

Single-sweep polarography of the copper(II)-3-hydroxy-1-p-sulphonatophenyl-3-phenyltriazene complex and its analytical applications.

A polarographic investigation of the copper-3-hydroxy-1-p-sulphonatophenyl-3-phenyltriazene (HSPT) complex in 0.05 M sodium tetraborate medium is described and a simple and sensitive single-sweep polarographic method for the determination of trace amounts of copper in biological samples is proposed. The complex was shown to be Cu(HSPT)2 with log beta' = 11.38. The polarographic wave is caused by the reduction of copper(II) in the adsorbed complex to copper amalgam on the surface of a mercury electrode. The current peak is directly proportional to the concentration of copper in the range 8.0 x 10(-9)-4.0 x 10(-6) M and the detection limit is 5.0 x 10(-9) M.

Copper↗
PubMed1994

Sensitive method for measuring lactate dehydrogenase activity in human serum by differential-pulse polarography.

A sensitive and accurate differential-pulse polarographic method is reported for the measurement of lactate dehydrogenase (LDH) activity. The method is based on the polarographic measurement of the NAD+ formed via the enzymic reaction of LDH with pyruvate and NADH. The method was successfully applied to measure LDH activity in the serum of normal and diseased individuals.

Disease↗
PubMed1996

Determination of cinnamic acid in human urine by differential-pulse polarography.

The differential-pulse polarographic behaviour of cinnamic acid was studied in acetate and phosphate buffer solutions (pH 3.5-7.5). The reduction mechanism is discussed. The drug can be determined at pH 5.0 over the concentration range 5 x 10(-5)-1 x 10(-3) mol l-1. The effect of tetraalkylammonium salts on the electroanalytical determination of cinnamic acid was investigated. The direct determination of the drug (0.7-5.5 micrograms ml-1) in urine samples diluted with acetate buffer (pH 5.0) can be effected in the presence of 1 x 10(-3) mol l-1 cetyldimethylethylammonium bromide solution. The detection limit was found to be 0.1 microgram ml-1. The relative standard deviation from six determinations at the 5.5 micrograms ml-1 level was 1%.

Cinnamates↗
PubMed1975

The determination of arsenite and arsenate ions in fish and shellfish by selective extraction and polarography.

Arsenite ion, as arsenic trichloride was extracted into benzene from strongly acidified tissue homogenates. Following this, arsenite was extracted from the benzene into water, made up in 1N HCl and analyzed polarographically. Arsenate ion, left in the homogenate after arsenite extraction is isolated in exactly the same way following treatment of the homogenate with cuprous ion to reduce arsenate to arsenite ion. Treatment of the acidified homogenate with cuprous ion prior to extraction gives a homogenate which is readily analyzed for total "inorganic" arsenic. The method was efficient to a maximum level of about 20 mug inorganic arsenic since at higher levels lower recoveries were found. Analysis of a variety of marine biological specimens, with levels of total arsenic up to 40.5 ppm, indicated little of this arsenic was present in an inorganic form. Post mortem reduction of arsenate to arsenite was found to occur rapidly in fish tissue.

Animals↗
PubMed2002

Use of polarography as a quality-control method for determining diacetyl in citrus and vegetable juices, yoghurt and butter.

The determination of diacetyl permits the detection of microbial growth in the processing of citrus fruit before the appearance of other organoleptic, chemical or microbiological changes. It also makes it possible to detect a break in the cold chain during distribution and sale. The study proposed a polarographic method for the determination of diacetyl that allowed routine analysis with the aim of detecting possible contamination in the citrus juice manufacturing chain (orange and orange-carrot). The analytical performance of the method in terms of a linearity from 0 to 960 microg ml(-1), a recovery of 97 to 98%, a precision of 3.2 to 4.8%, and a sensitivity of 0.2 ng ml(-1) for juices indicated the robustness of the method. The same method was also applied to butter and yoghurt with detection limits of and 0.4 ng g(-1).

Beverages↗