Capillary zone electrophoresis of proteins with a dynamic surfactant coating: influence of a voltage gradient on the separation efficiency

In capillary zone electrophoresis of proteins, the adsorption of the proteins on the capillary wall is a considerable problem that seriously impairs the sepn. efficiency. The use of a dynamic surfactant coating is a possible way to diminish this adsorption. Highly efficient sepns. were achieved with a cationic fluorinated buffer additive as a dynamic surfactant coating in untreated fused-silica capillaries at neutral pH. The influence of a voltage gradient on the sepn. efficiency is discussed and a simple relationship is presented to calc. effective mobilities under voltage gradient condition

Isotachophoretic analyses of compounds in complex matrixes : allergenic extracts and aluminium in biological fluids and bone

The aim of this publication is to show the great versatility of capillary isotachophoresis: (glyco)proteins versus small cations like aluminium. For the separation of allergenie extracts the UV-patterns obtained. were highly reproducibile. which makes quali ty control and characterisation of these extracts possible. The determination of aluminium in bone (0.57 g) is possible. when a preconcentration step is used. No disturbing matrix were observed

Determination of uric acid in serum using isotachophoresis

An operational system is described for the isotachophoretic determination of uric acid in serum, making use of column coupling. The method has been compared with a standard enzymatic procedure. With the present technique small amounts of serum (ca. 3 μl) can be applied without any pretreatment. Urate recovery was 99.0–100.5%. Under the non-physiological measuring conditions used, 12–28% of control serum uric acid was bound to macromolecules of molecular weight exceeding 25,000. The day-to-day variations of the isotachophoretic procedure were smaller than those of the enzymatic method, whereas standard deviations were comparable. The isotachophoretic procedure is less influenced by certain metabolites

The role of lipid-associated sialic acid (LSA) and prostate specific antigen (PSA) in the follow-up of prostatic cancer

According to the most recent US cancer statistics, prostatic cancer almost equals lung cancer as the most frequent cause of death from cancer in men. The search for diagnostic methods as well as control examinations have therefore gained great importance. The present study reveals that--in addition to rectal touch, sonography and biopsy of the prostate--the determination of both PSA as organ-specific marker and lipid-associated sialic acid (LSA) as a general tumor marker, is well suited for follow-up and monitoring treatment. With regard to the follow-up, the combined determination of PSA and LSA in serum of patients with prostatic cancer achieves a higher sensitivity as compared to PSA alone (increase of 30-40%). LSA is a good indicator for the presence of metastases. Therefore, the determination of LSA should become an integral part of treatment monitoring and detection of metastatic disease in patients with prostatic cancer

Analysis of serum purines and pyrimidines by isotachophoresis

Purine and pyrimidine metabolism receive attention from a rapidly growing number of workers in the field of inborn errors (1), hematology (2), immunology (3) and oncology (4,5). The availability of metabolite profiles of body fluids and cell contents might attribute to a better understanding of mechanisms underlying metabolic disturbances. This enables a more direct approach for both diagnostic and experimental purposes. For identification of purines and pyrimidines thin-layer high voltage electrophoresis and chromatography can be used (6). A more rapid technique involves high performance liquid chromatography (HPLC) and is widely used at present (7,8). An alternative to HPLC for a screening of metabolite profiles might be isotachophoresis (9). This technique has recently been introduced for the separation and identification of muscle nucleotides (10) and urinary purines and pyrimidines (11). An advantage of isotachophoresis as compared to HPLC is its flexibility: buffers can be changed rapidly, no columns need to be equilibrated. In this paper two systems are presented for the separation of a number of purines and pyrimidines in serum: one low-pH system (pH 3.9) for nucleotides and one high-pH system (pH 7.75) for bases and nucleosides