High performance capillary electrophoresis HPCE

A high performance capillary electrophoresis (HPCE) was described for the separation and simultaneous determination of OTC, TC, CTC, DC, and chloramphenicol in honey. The use of buffer pH 3.2 containing 0.02 mol/L Na2HP04 and 0.01 mol/L citric acid with addition of 4% (v/v) A-methylmorpholine and 12% (v/v) acetonitrile demonstrated a good separation of these five antibiotics within 20 min. The proposed method gave detection limit (signal to noise ratio > 5) of 20 pg/L for OTC [26],... 

A further improvement of the more traditional slab gel analysis is the use of high-performance capillary electrophoresis (HPCE), which combines the separation power of high-performance liquid chromatography (HPLC) with the selectivity and speed of conventional gel electrophoresis. However, as HPCE separations are often performed using fused silica capillaries the positively charged histone molecules... 

The reader is directed to Ref. 5, which makes an interesting comparison between HPLC and other analytical methodologies for the determination of carbohydrates in foods. Additionally, notable progress has been made in the application of high-performance capillary electrophoresis (HPCE) in this field (8-11). However, given the scope of this chapter, we will focus on the advantages and drawbacks of other chromatographic techniques versus HPLC. 

In this book, the focus is on the use of high performance liquid chromatography (HPLC) for the separation and detection of biochemical components produced from enzymatic reactions. But the purpose of the book is also to introduce HPLC and high performance capillary electrophoresis (HPCE) as methods applicable for separation and detection of a variety of components, even those not produced by enzymatic reactions. 

Using these criteria as yardsticks, the first edition has been a success. It is now obsolete, however Because of the increases in both number and types of activities assayed, it is no longer an accurate catalog of enzymatic activities investigated by means of the HPLC method. For this work to continue to serve as a reference source, it would need updating. While it was the obsolescence of the first edition that in part prompted the development of a second edition, there were other considerations as well. These included the introduction of high performance capillary electrophoresis (HPCE) as a method for separation, the development of microdialysis as a method for collection of samples... 

Most forms of detection in High-Performance Capillary Electrophoresis (HPCE) employ on-capillary detection. Exceptions are techniques that use a sheath flow such as laser-induced fluorescence [1] and electrospray ionization mass spectrometry [2],... 

The solution contained within the capillary in which the separation occurs is known as the background electrolyte (BGE), carrier electrolyte, or, simply, the buffer. The BGE always contains a buffer because pH control is the most important parameter in electrophoresis. The pH may affect the charge and thus the mobility of an ionizable solute. The electro-osmotic flow (EOF) is also affected by the buffer pH. Table 1 contains a list of buffers that may prove useful in high-performance capillary electrophoresis (HPCE). As will be seen later, only a few of these buffers are necessary for most separations. 

One cannot overestimate the importance of fluorescence detection in high-performance capillary electrophoresis (HPCE) [1], The success of the human genome project along with the forthcoming revolutions in forensic testing and genetic analysis might not have occurred without the sensitivity and selectivity of laser-induced fluorescence (LIF) detection. 

A very interesting task would be automatic measurement of the product and the calculation of production rates. This would allow automatic optimization of the process by a computer program that varies all relevant parameters, probably by multiparameter analysis, to find the best production conditions. As long as there are no product sensors available, the main problem may be the time necessary for the measurement of an automatically taken sample. However, the use of HPLC methods can give accurate results within 20 min, and high-performance capillary electrophoresis (HPCE), with an analysis time of 5 min, could be introduced (Beckman PIACE 2(X)0, E. Wasserbauer, personal communication and James et al, 1994). Nonetheless, further development is necessary before these methods can be used routinely for automatic fermentation analysis. 

X Liu, M Hou. Determination of compounds in common cold preparations by high performance capillary electrophoresis (HPCE). Yaowu Fenxi Zazhi 17 315-318, 1997. 

Electrophoretic assays may be used to characterize the purity and homogeneity of biopharmaceuticals, based mainly on an ability to differentiate chemical and molecular changes in the compound as a result of oxidation, denaturation, aggregation, and deamidation [11]. Well-established techniques include isoelectric focusing (lEF) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), whilst high-performance capillary electrophoresis (HPCE), utilizing a variety of detection systems, may also be used for routine applications. 

Highly active antiviral therapy, see HAART High-performance capillary electrophoresis (HPCE) 1563... 

Although not completely correct, CEC is often presented as a hybrid method that combines the capillary column format and EOF typical of high-performance capillary electrophoresis (HPCE) with the use of a solid stationary phase and a separation mechanism based on specific interactions of solutes with a stationary phase characteristic of HPLC. Therefore, CEC is most commonly implemented by means typical of both HPLC (packed columns) and HPCE (electrophoretic instrumentation). To date, both columns and instrumentation developed specifically for CEC remain scarce. 

SFC uses the same stationary phases as FIPLC. Selectivity is similar but not identical. One of the greatest differences from n-FIPLC is in speed. SFC optimum flow is inherently three to five times faster, while peak shapes are often significantly better. Unlike n-HPLC, SFC reequilibrates after passage of only a few column volumes. Overall, SFC is often much more than 10 times faster than FIPLC. A fast chiral SFC separation is shown in Figure 4. Note that the column is not high speed but a standard 4.6x250 mm column with 10 pm particles. Some industrial pharmaceutical companies have dropped HPLC for chiral analysis and use SFC for less polar solutes, and high-performance capillary electrophoresis (HPCE) for water-soluble solutes. Unlike HPCE, SEC is scalable. 

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