ABSTRACT
The statistical characteristics of the intracavity laser spectrometer are investigated by analysis of cesium in aqueous solutions. The error distribution of measurements is normal. The relative standard deviation of the analysis in the middle of the dynamic range is equal to 9.7%. The intracavity spectral analysis was carried out at low contents of cesium, manganese and terbium in aqueous solutions. The limits of detection are: 5 microg l(-1) (Cs), 20 microg l(-1) (Mn) and 1000 microg l(-1) (Tb). Owing to the high spectral resolution of the spectrometer used the hyperfine structure of the thallium absorption line (535.05 nm) was recorded.
ABSTRACT
The influence of isolation procedures on physico-chemical properties of human serum albumin (HSA) has been studied using differential scanning calorimetry and infrared spectroscopy. Fractionation of blood plasma with polyethylene glycol (PEG) followed by ion-exchange chromatography produced healthy donor albumin whose melting thermograms were identical to those of the HSA in non-fractionated plasma. The endotherms of HSA samples isolated by affinity chromatography (AC) and native electrophoresis (EP) are bimodal as distinct from monophasic endotherms of PEG-HSA preparations. The changes in the melting curves result from increased levels of nonesterified fatty acids in AC-HSA samples and modification of the protein secondary structure revealed in EP-HSA samples by IR-spectroscopy. Analysis of HSA melting thermograms in patients with uremia, chronic hepatitis and peritonitis revealed that the PEG method permits to preserve, in the greatest degree, the thermodynamic features of various "pathological" HSA. The experimental results demonstrate the advantage of the PEG technique in isolation of native HSA in the norm and under pathology.
Subject(s)
Serum Albumin/chemistry , Calorimetry, Differential Scanning , Chromatography, Affinity , Chromatography, Ion Exchange , Electrophoresis, Polyacrylamide Gel , Fatty Acids, Nonesterified/analysis , Humans , Ligands , Protein Structure, Secondary , Serum Albumin/isolation & purification , Serum Albumin/metabolism , Spectrophotometry, InfraredABSTRACT
The authors suggest a new improved automated method for separate measurements of urinary porphyrins (coproporphyrins and uroporphyrins) in native urine with computer processing of spectral data. The method of dividing the total spectrum of porphyrin fluorescence takes account of background non-porphyrin admixtures in the urine and corrects the data on the basis of regression analysis. The data of this method were compared to those of other widely used methods and were found to be in good correlation; the advantages of the automated method are discussed.
