We describe a new technique for monitoring intra-cuvette temperatures in temperature-controlled spectrophotometric cells by use of two solutions, one for which absorbance is highly sensitive to temperature and one for which absorbance is insensitive to temperature. The first solution, cresol red in tris(hydroxymethyl)aminomethane buffer, is used to construct an absorbance-vs.-temperature calibr...

Application of multivariate curve resolution alternating least squares (MCR-ALS), for the resolution and quantification of different analytes in different type of pharmaceutical and agricultural samples is shown. In particular, MCR-ALS is applied first to the UV spectrophotometric quantitative analysis of mixtures of commercial steroid drugs, and second to the near-infrared (NIR) spectrophotome...

Hemoglobin interferes with determination of total bilirubin by the diazo procedure with the DuPont aca. We compared results by that procedure with those by a manual direct spectrophotometric two-wavelength method. Because the manual method was not inhibited by hemolysis as was the DuPont aca diazo procedure, we reprogrammed our DuPont aca to measure the absorbance of diluted serum samples at 45...

Several methods for determining urea in blood and urine are in use in clinical laboratories, but none is ideal in mass routine analysis. The spectrophotometric method based on a modified Ehrlich reagent proposed by Watt and Chrisp (1954) for pure solutions is therefore of interest because it can be modified for use in mass clinical analyses of blood and urine. Brown (1959) has modified the meth...

A lag phase in the spectrophotometric assay progress curve of aldehyde oxidation by HL-ADH was observed and characterised. The aldehyde oxidation and aldehyde dismutation reactions were shown to be related, and a mechanism to explain net aldehyde oxidation was proposed. The spectrophotometric assay was shown to be unsuitable for measurement of kinetic parameters for aldehyde oxidation by HL-ADH...

This study aims to determine the concentration of phenol in different types of apples (green, yellow and red), tea and coffee. Samples were taken from different sources and were determined by spectrophotometric method. One sample of each type of apple (green, red, yellow) coffee and tea were considered. The results show high concentration of phenol in all samples of apples, coffee and tea compa...

The glass surface modification with 3-(mercaptopropyl) trimethoxysilane (MPTS), gold nano-particles (GN) and guanine rich single strand DNA (ss-DNA) was utilized as a novel and efficient platform for sensing trace concentration of methylene blue (MB) by an inexpensive spectrophotometric method. Methylene Blue (MB) can interact with the guanine base of single strand DNA and absorbed onto glass s...

an extraction-spectrophotometric method for the determination of trace amounts of ammonium ion is described. ammonium ion is effectively extracted as a neutral ternary complex nh . db 18c6. calmagite at ph 3.0 into chloroform, followed by spectrophotometric determination at =48 5 nm. molar absorptivity of the ternary complex at this wavelength is 1.08 10 mol cm . beer's law is obeyed over ...