Microdetermination of proteins with the arsenazo-DBN-Al(III) complex by Rayleigh light-scattering technique and application of the method

A Highly Sensitive and Rapid Assay for Protein Determination in Human Urine and Penicillin Using a Rayleigh Light-Scattering Technique with Benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic Acid Sodium Salt

A simple and sensitive method was conducted for the determination of trace amounts of proteins with benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic acid sodium salt (azophloxine, AP) using a Rayleigh light-scattering (RLS) technique. At pH 2.60 and in the presence of an emulsifier OP microemulsion, the RLS of AP can be greatly enhanced by proteins, owing to the interaction between AP and protein. The enhanced intensity is proportional to the concentration of proteins. Four proteins, including bovine serum albumin (BSA), human serum albumin (HSA), lysozyme (Lys) and gamma globulin (gamma-G) have been tested. For example, the linear range of BSA was 0 - 0.06 microg mL(-1) with detection limits of 2.38 ng mL(-1). The method was applied to the analysis of protein in human urine and penicillin samples with satisfactory results. The relative standard deviation was in all instances less than 4.0%, and the recovery was in the range of 97.5 - 104%.

Rapid determination of ultra trace amounts of residual protein in penicillin based on its enhancement effects of Rayleigh light scattering on trimethoxyphenlyfluorone (TM-PF)–Mo(VI) complex

This is a report on the ultra trace amount determination of protein in penicillin based on the interaction with trimethoxyphenlyfluorone (TM-PF)-molybdenum (Mo)(VI) complex in the presence of Triton X-100 microemulsion by Rayleigh light scattering (RLS). At pH 2.70, the weak RLS of TM-PF-Mo(VI) complex was enhanced greatly by the addition of proteins. Based on this, the interaction of TM-PF-Mo(VI) complex with proteins was studied and a new quantitative determination method for proteins was developed. This method is extremely sensitive (the linear range of the calibration curve was 0-80 ng mL(-1) for bovine serum albumin (BSA). The detection limit was 0.47 ng mL(-1)), simple, steady and free from interference of coexisting substances. TM-PF-Mo(VI) complex as a spectral probe can be used to the determination of the residual protein in penicillin samples successfully.

Proton T1 and T2 relaxivities of serum proteins

In the present study, T(1) and T(2) of phantoms containing serum sets with varying amounts of proteins, serum samples with certain amounts of proteins, serum diluted by distilled water, and serum treated with iron were measured. In addition, T(1) and T(2) of phantoms containing normal serum, diluted serum, and albumin-doped serum were also measured. Relaxation rates were plotted versus protein concentrations. The slope of relation was taken as relaxivity. The T(1) relaxivities of proteins were ranged from 0.035 to 0.080 s(-1)(g/dl)(-1), whereas T(2) relaxivities were ranged from 0.24 to 0.68 s(-1)(g/dl)(-1). The T(1) and T(2) relaxivities of transferrin iron were 2.40 and 2.60 mM(-1)s(-1), respectively. The contributions of diamagnetic proteins and transferrin iron to the relaxation rate of serum were also calculated for each of diluted serum, normal and albumin-doped serum. The contributions and the average TP relaxivities(calculated by using individual relaxivities and the ratios of protein fractions in TP) were used for TP calculations. The agreement between the calculated TP and TP by autoanalyzer and also the agreement between average TP relaxivities and the TP relaxivities determined from dilution experiments show that the data of relaxivities are reliable. The results suggest that individual protein relaxivities explain the influence of serum TP composition on T(1) and T(2) relaxation times.