INTRODUCTION Because of its chemical diversity, the only way to standardise propolis is to specify multiple standards for different propolis types according to the corresponding chemical profile. So far, this has been done only for European propolis. OBJECTIVE To develop a rapid low-cost spectrophotometric procedure for quantification of bioactive prenylated flavanones in Taiwanese propolis. ...

The ratio of absorbance at 260 and 280 nm (the A260/280 ratio) is frequently used to assess the purity of RNA and DNA preparations. Data presented in this report demonstrate significant variability in the RNA A260/280 ratio when different sources of water were used to perform the spectrophotometric determinations. Adjusting the pH of water used for spectrophotometric analysis from approximately...

To develop a new more accurate spectrophotometric method for detecting monoamine oxidase inhibitors from plant extracts, a series of amine substrates were selected and their ability to be oxidized by monoamine oxidase was evaluated by the HPLC method and a new substrate was used to develop a peroxidase-linked spectrophotometric assay. 4-(Trifluoromethyl) benzylamine (11) was proved to be an exc...

Context. One of the key ingredients in establishing the relation between input signal and output flux from a spectrometer is accurate determination of the spectrophotometric calibration. In the case of spectrometers onboard satellites, the accuracy of this part of the calibration pedigree is ultimately linked to the accuracy of the set of reference spectral energy distributions (SEDs) that the ...

Present study deals with two Spectrophotometric methods, Conventional Spectrophotometric Estimation and Area under Curve Method and a chromatographic method for estimation of Cefixime by using five different hydrotropic agents. These include Ammonium acetate (6M), Potassium acetate (5M), Potassium citrate (0.5 M), Sodium citrate (1.25 M) and Urea (8M). Area under curve method was based on measu...

An optical chemical sensor has been developed for the quantitative spectrophotometric analysis of copper.

Purpose: To improve the sensitivity and specificity of spectrophotometric 3-hydroxy-3-methylglutarylcoenzyme A (HMG-CoA) reductase activity assay. Methods: Spectrophotometric HMG-CoA reductase detection in male Wistar rat liver microsomes was optimized by applying different conditions, such as reaction buffer pH, NADPH and protein concentration, and preincubation and reaction times. The optimal...

BACKGROUND Biotin, a water-soluble vitamin, is used as a co-factor by enzymes involved in carboxylation reactions. Biotinidase (BTD) catalyzes the recycling of biotin from endogenous and dietary sources. Biotinidase deficiency (BD) is an autosomal recessively inherited disorder of biotin recycling that is associated with neurologic and cutaneous consequences when untreated. The aim of the study...

OBJECTIVES To assay theophylline blood levels in a sample of Sri Lankan chronic asthmatics taking oral theophylline, and to evaluate a simple and cost effective ultraviolet spectrophotometric assay for theophylline levels in blood. SETTING Chronic asthmatics taking oral theophylline attending medical clinics at the National Hospital of Sri Lanka (NHSL) were recruited for the study. Blood samp...

It is the purpose of the research reported in the present series of papers to establish accurate spectrophotometric procedures for the determination of iron, more particularly for use in biochemical and nutrition studies, but applicable generally to the analysis of biological materials, foods, pharmaceuticals, and chemical reagents. Several calorimetric methods for the determination of iron are...