Quantitative analysis electrophoresis

We have developed the method for quantitative analysis of urinary albumin with CE. A capillary electrophoresis systems Nanophor 01 (Institute of Analytical Instmmentation, Russian Academy of Sciences, Saint-Petersburg) equipped with a UV-detector was used to determine analyte. Separation was achieved using 45 cmx30 p.m I.D. fused silica capillary column with UV-detection at 214 nm. 

Slater, GW Rousseau, J Noolandi, J Tunnel, C Lalande, M, Quantitative Analysis of the Three Regimes of DNA Electrophoresis in Agarose Gels, Biopolymers 27, 509, 1988. 

Desiderio, C., Marra, C., and Fanali, S., Quantitative analysis of synthetic dyes in lipstick by MEKC, Electrophoresis, 19, 1478, 1998. 

Schmidt, T., Friehs, K., Schleef, M., Voss, C., and Hasche, E., Quantitative analysis of plasmid forms by agarose and capillary gel electrophoresis, Anal. Biochem., 274, 235, 1999. 

As the name implies, capillary electrophoresis is electrophoresis that is made to occur inside a piece (50 to 100 cm) of small-diameter capillary tubing, similar to the tubing used for capillary GC columns. The tubing contains the electrolyte medium, and the ends of the tube are dipped into solvent reservoirs, as is the paper in paper electrophoresis. Electrodes in these reservoirs create the potential difference across the capillary tube. An electronic detector, such as those described for HPLC (Chapter 13), is on-line and allows detection and quantitative analysis of mixture components. 

Capillary electrophoresis is an electrophoresis technique in which the mixture components are separated in a capillary tube and detected with an on-line detector after the separation occurs. The advantages include smaller quantity of sample and qualitative and quantitative analysis in a much shorter time. 

The identification and quantitation of the individual amino acids in a mixture is often required in metabolic studies and investigations of protein structure. The use of thin-layer chromatography or electrophoresis may be adequate to indicate the relative amounts and number of different amino acids in a sample but the use of gas-liquid chromatography or an amino acid analyser is essential for quantitative analysis. 

Lozano, R., Warren, F. V., Perlman, S., and Joseph, J. M. (1995). Quantitative analysis of fosinopril sodium by capillary zone electrophoresis and liquid chromatography. /. Pharm. Biomed. Anal. 13, 139-148. 

Juan-Garcia, A., Font, G., and Pico, Y. (2005). Quantitative analysis of six pesticides in fruits by capillary electrophoresis-electrospray-mass spectrometry. Electrophoresis 26, 1550—1561. 

Soga, T., Kakazu, Y., Robert, M., Tomita, M., andNishioka, T. (2004). Qualitative and quantitative analysis of amino acids by capillary electrophoresis-electrospray ionization-tandem mass spectrometry. Electrophoresis 25, 1964—1972. 

For quantitative analysis by electrophoresis, normalized peak areas are required. The normalized peak area is the measured peak area divided by the migration time. In chromatography, each analyte passes through the detector at the same rate, so peak area is proportional to the quantity of analyte. In electrophoresis, analytes with different apparent mobilities pass through the detector at different rates. The higher the apparent mobility, the shorter the migration time and the less time the analyte spends in the detector. To correct lor time spent in the detector, divide the peak area for each analyte by its migration time. 

Data from electrophoresis is normally recorded photographically. Densitometry may also be performed on the stained gel or bands may be excised/eluted for further analysis (Mayer et al., 1998). The bands may also be isolated from the gels by blotting methods such as electroblotting (McSweeney et al., 1994 O Malley et al., 2000) or immunoblotting (Addeo et al., 1995 Moio et al., 1992) for further characterization and identification. All of the electrophoretic methods, to a certain extent, provide good quality data. But due to the difficulty in quantitative analysis, very few examples are available on the quantification of protein fractions using... 

Quantitative analysis of chemical warfare agent degradation products in reaction masses using capillary electrophoresis, Anal. Chem., 70, 3598-3604 (1998). 

The same authors also applied capillary electrophoresis to the study of benazepril hydrochloride and several angiotensin-converting enzyme inhibitors [43]. Separation of the compounds was performed by means of two phosphate buffers (each 0.1 M) at pH 7 and 6.25, respectively [42], Due to the highest selectivity of the first mentioned running buffer, the same system has been applied for the quantification of benazepril and other compounds in their corresponding pharmaceutical formulations. It was found that the possibility of simultaneous identification and quantification of the active ingredient in the finished products was especially attractive, and that excipients do not adversely affect the results. This article deals with the validation of some parameters of the quantitative analysis, namely linearity, precision, accuracy, and robustness [43],... 

CGE offers an alternative that provides fast separations, quantitative analysis, and automated operation. High-level sensitivity detection (500 ng/mL protein) is possible with this technique.22 Compounds such as nucleic acids and SDS-protein complexes that possess the same mass-to-charge ratios cannot be resolved by CZE. To separate these species, electrophoresis must be performed in a medium in which the rate of migration depends on molecular size. CGE is useful for these separations. A material such as... 

---