CE separation of various analytes of biological origin using polyether ether ketone capillaries and contactless conductivity detection

Abstract

The development of efficient and sensitive analytical methods for the separation, identification and quantification of complex biological samples is continuously a topic of high interest in biological science. In the present study, the possibility of using a polyether ether ketone (PEEK) capillary for the CE separation of peptides, proteins and other biological samples was examined. The performance of the tubing was compared with that of traditional silica capillaries. The CE analysis was performed using contactless conductivity detection (C(4)D), which eliminated any need for the detection window and was suitable for the detection of optically inactive compounds. In the PEEK capillary the cathodic EOF was low and of excellent stability even at extremes pH. In view of this fast biological anions were analyzed using an opposite end injection technique without compromising separation. A comparison of the performances of fused-silica and polymer capillaries during the separation of model sample mixtures demonstrated the efficiency and separation resolution of the latter to be higher and the reproducibility of the migration times and peak areas is better. Furthermore, PEEK capillaries allowed using simple experimental conditions without any complicated modification of the capillary surface or use of an intricate buffer composition. The PEEK capillaries are considered as an attractive alternative to the traditional fused-silica capillaries and may be used for the analysis of complex biological mixtures as well as for developing portable devices.

Capacitively coupled contactless conductivity detection for microseparation techniques – recent developments

“…Knjazeva et al . 54 investigated the use of polyether ether ketone capillaries for the separation of organic acids, peptides, and proteins and the reported advantages of the polymeric material compared to fused silica are a low intrinsic electroosmotic flow, excellent stability even at extreme pH values, and reduced adsorption of matrix compounds from biological samples.…”

Capillary electrokinetic fractionation mass spectrometry (CEkF/MS): Technology setup and application to metabolite fractionation from complex samples coupled at‐line with ultrahigh‐resolution mass spectrometry

“…A PEEK tubing without Si‐OH group producing EOF was introduced as the work capillary for this purpose. Previous research has claimed that the EOF in PEEK tube was around 2.6 × 10 −4 cm 2 /Vs, which is more than half lower than that in fused‐silica capillary at equivalent pH . Moreover, when the tube is electrokinetically filled in excess, the sole factor effect on the amount of the filled sample is the relative higher concentration of the ionized fraction in the free solution.…”

Applications of capillary electrophoresis with capacitively coupled contactless conductivity detection (CE‐C4D) in pharmaceutical and biological analysis

“…Knjazeva et al. (2009) examined the using of a polyether ether ketone (PEEK) capillary for the CE separation of peptides, proteins and other biological samples. The performances of fused‐silica and polymer capillaries were compared.…”