A COLORIMETRIC DETERMINATION OF NICOTINIC ACID

A colorimetric reaction for the quantitative estimation of nicotinic acid.

The Microbiological Determination of Nicotinic Acid, Nicotinamide, and Nicotinuric Acid

The nicotinic acid assay most generally satisfactory is the Lactobacillus arabinosus procedure (1, 2) as regards sensitivity and non-interference from other compounds. However, this organism responds to nicotinamide and nicotinuric acid as well as to nicotinic acid. Gaines and Stahly (3) have proposed the use of Leuconostoc mesenteroides for the assay of several members of the vitamin B complex...

Colorimetric determination of hippuric acid in urine and liver homogenate.

To a dried extract Containing hippuric acid (HA), 1.0 mL of acetic anhydride and 2.0 mL of 0.5% p-dlmethyiamlnobenzaldehyde (DAB) solution In pyridine were added, and the solution was kept at 40 O C for 1 h after thorough mlxing. The absorbance was then determlned at 458 nm agalnst a blank containing acetic anhydride, DAB, and pyridine. This method was in good agreement with Beer’s law within 1...

Direct colorimetric determination of hippuric acid in urine.

In 1963 Umberger and Fiorese (1) introduced a colorimetric method for HA,1 based on the color reaction of HA, dissolved in anhydrous pyridine, with BSC. Therefore, for applying their method to determine HA in urine, HA must first be extracted from the urine. We found that HA dissolved in water-pyridine (1:1, by vol) produces a red-orange color when BSC is added at room temperature. The absorpti...

The Colorimetric Determination of Lactic Acid in Biological Material