Three turbidometric methods and one method using ultraviolet spectrophotometry for estimating total cerebrospinal fluid protein have been examined. The necessity for preliminary dialysis renders the ultraviolet method unsuitable for routine use. The turbidometric method of Meulemans (1960) using a sulphosalicylic acid-sodium sulphate precipitating fluid is better than a method using sulphosalic...

Typically, the first thing one wants to know about a DNA preparation is its concentration and purity. Both can be determined by measuring the absorption of ultraviolet light. DNA absorbs UV more or less strongly depending upon the wavelength. We will be using a NanoDrop spectrophotometer, which takes measurements at wavelengths of 260 and 280 nm, and in addition determines an absorption spectru...

PURPOSE To determine the UV absorbance of the corneal layers (epithelium, Bowman layer, stroma) in the 240- to 400-nm range. METHODS Consecutive slices (100 microm) of human cadaveric corneas were cut, and the UV absorbance of each sample was determined in a scanning spectrophotometer. In some cases the epithelium was scraped off and its absorbance measured separately. RESULTS The investiga...

This paper deals with a new method for the estimation of vitamin A in blood serum based on the new calorimetric reaction between vitamin A and activated glycerol dichlorohydrin (GDH) . Most of the available methods for estimating vitamin A in blood serum depend upon the antimony trichloride reaction (l-6). The drawbacks to this reaction are that (1) the color is unstable and must be read within...

We describe a fluorescence spectrophotometer adapted with a micro quartz flow cell to record the output of modern liquid chromatographs. The optical system is double beam in that the light source variations are cancelled out by a second photomultiplier, thus enhancing the sensitivity of the technique. The emission spectra may be scanned by stopping the flow in the chromatographic column and sca...

The aim of this research was to investigate the effect of the duration of ultrasonication energy on the physicochemical characteristics of the nano-sized particulate drug delivery systems. For this purpose, meloxicam-loaded vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-emulsified poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles were designed by using ultrasonication-sol...

We succeeded to develop a reference light source in the range of very low luminance using a double integrating sphere system, and calibrated a commercial spectrophotometer below 1 × 10−5 cd/m2 levels, which is 1/100 lower than the specified limit for measurement. And we improved measurements in the ultra low luminance range of displays using the calibrated commercial spectrophotometer and a dar...

In this research project, the nitrito nitro isomerization of [Co (NH3)5No2]F2 complex has been studied. Isomerization of this complex in the solid state follows a first order kinetics. The rate of isomerization at different temperatures was determined using a Fourier Transform Lnfrared Spectrophotometer. ? and ? are calculated at 298 K. The infrared, visible and ultraviolet spectra of th...