Untitled

Analysis of chemical processes at single bovine adrenergic chromaffin cells with micellar electrokinetic capillary chromatography and electrochemical detection

“…The average amounts of norepinephrine and epinephrine found in several adrenal cells determined by MEKC-EC are 33 l 14 and 25 l 11 fmol, respectively. This total catecholamine content of 58 fmol can be estimated to be contained in 11,000 vesicles, assuming an average vesicular content of 5 amol [4]. These results are relatively consistent with similar studies using microcolumn LC [7,8,38] or CZE with native fluorescence detection [36], although the absolute amounts of catecholamines detected here are generally a bit lower.…”

“…In addition, chemical selectivity is necessary to distinguish between the different compounds that may be present in the sample. Micro-electrochemical techniques have been used extensively to study the release of electroactive compounds from single cells [4]. These methods offer tremendous temporal and spatial resolution as well as high sensitivity, but generally suffer from poor chemical selectivity.…”

A weak cation-exchange phase for the separation of biogenic amines by open tubular liquid chromatography

“…This limitation seriously restricts the applicability of OT-LC. Biologically active compounds like amino acids and catecholamines are charged and have important functions in health and disease states [10,11]. An OT-LC separation procedure for these compounds could be of considerable interest, because the extremely small sample size needed is often of great importance in biological studies [12][13][14].…”