Laser-induced fluorescence and fluorescence microscopy for capillary electrophoresis zone detection

Hernández, Luis; Escalona, José; Joshi, N.V.; Guzman, Norberto A.

doi:10.1016/0021-9673(91)80069-s

Cited by 117 publications

(48 citation statements)

References 22 publications

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“…Using a collection fiber, the fluorescence signal was directed into a monochromator and detected with a photomultiplier tube (PMT) acids was possible. Hernandez and co-workers [42,43] report zeptomole mass detection limits (10 ±13 M concentration LODs) for a series of derivatized amino acids using their collinear LIF detector. In this arrangement, the angle between the exciting laser beam and the collected fluorescence is 0 o , which reduces laser scattering by the walls of the capillary, leading to lower background signals and enhanced collection of the fluorescence signal.…”

Section: Direct On-column Detectionmentioning

confidence: 99%

Detection in capillary electrophoresis

2000

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Section: Direct On-column Detectionmentioning

confidence: 99%

Detection in capillary electrophoresis

2000

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“…They obtained a limit of concentration detection at 10 À10 M level. The introduction of post-column detection in a sheat flow cuvette [14] or collinear geometry [26] lowered the limit of concentration detection to 10 À13 M. These improvements made single molecule detection the ultimate level of precision for CZE analysis [15,[27][28][29][30]. As a consequence, the CE high resolution power and sensitivity within the zeptomolar range (10 À21 M) made possible the successful use of CE-LIFD in endogenous neuroactive substances, DNA and illicit drug analysis [5,6,31].…”

Section: Detection Techniques Coupled To Cementioning

confidence: 99%

Biomedical applications of capillary electrophoresis with laser‐induced fluorescence detection

Páez

Hernández

2001

Biopharm & Drug Disp

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Capillary electrophoresis (CE) is a high-efficiency analytical technique that has had a great impact as a tool in biomedical research, clinical and forensic practice in the last ten years. Only in one of the applications, the DNA analysis, it has had an explosive exponential growth in the last few years. This impact is expressed in an enormous amount of CE articles and many reviews. The CE advantages with respect to other analytical techniques: the required very small sample volume, rapid analysis, great resolution power and low costs, have made this technique ideal for the analysis of a numerous endogenous and exogenous substances present in biological fluids. The different modes of CE have been coupled to different detection techniques such as UV-absorbance, electrochemical, mass spectrometry and laser-induced fluorescence detection (LIFD) to detect different nature and molecular size separated analytes. This review focuses mostly on the applications of CE-LIFD, to measure drugs and endogenous neuroactive substances such as amino acids and monoamines, especially in microdialysis samples from experimental animals and humans. CE-LIFD trends are discussed: automated faster analysis with capillary array systems, resolution power improvement, higher detection sensitivity, and CE systems miniaturization for extremely small sample volume, in order to make CE easier and affordable to the lab bench or the clinical bed.

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“…We are currently able to measure three neuropeptides (LHRH, neuropeptide Y and |)-endorphin) in each PPC sample (100 ul) obtained at 10-min intervals [7,25]. In addition, we have de veloped a chromatographic assay, based on capillary elec trophoresis and fluorescence detection of derivatized neuropeptides, that allows femtogram determination of components in 120 nl of PPC perfusate [26], An even better detection sensitivity has been reported using capillary electrophoresis coupled to laser-induced fluo rescence [27].…”

Section: Discussionmentioning

confidence: 99%

Serial Long-Term Assessment of in vivo LHRH Release from a Discrete Area of the Ewe Median Eminence Using Multiple Guide Cannula Assembly and Removable Push-Pull Cannulae

Conover

Kuljiš²,

Rabii³

et al. 1993

Neuroendocrinology

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Analysis of neuronal interactions at the median eminence (ME) that control anterior pituitary function requires sampling of in vivo release of specific hypophysiotropic components and of putative inputs that might regulate such a release. We developed a multiple guide cannula assembly (MGCA) to sample repetitively discrete areas of the ewe ME, using removable push-pull cannula (PPC) probes. The MGCA is attached to the skull over the ME using stereotaxic surgery. A specific guide cannula of the assembly (1 of 48 guides) located on the midline and directly on top of the central portion of the ME is selected based on roentgenograms obtained after infusion of radiopaque contrast material into the third ventricle. The MGCA and the large size of the ewe brain allows the simultaneous positioning of a PPC probe, an infusion cannula or another removable probe in additional discrete hypothalamic and extrahypothalamic areas. To determine the capabilities of this sampling technique, we assessed in vivo release of LHRH from the extracellular space at the posterior-lateral ME, under various reproductive conditions that have well-defined LH-secretory patterns. The pulsatile profile of both LHRH and LH was significantly lower in anestrus than during the follicular phase of cycling ewes. In vivo pulsatile release of LHRH was higher in the follicular than in the midluteal phase of ewes sampled repetitively from the same ME site during three consecutive estrous cycles. All ewes showed increased midluteal progesterone levels. In vivo LHRH release, as determined by PPC sampling of the extracellular fluid at the posterior-lateral ME, probably reflects a mix of hypophysiotropic and nonhypophysiotropic LHRH components. Histological analysis revealed a well-organized, pallisade-like array of astroglial processes along the track of chronically implanted cannulae. This glial scar is disrupted along the tracks of acutely reimplanted cannulae but without apparent difference in the yield of the method. Our method increases the efficiency and versatility of ME PPC sampling providing an additional tool to assess the role of the ME as the final neuroendocrine control site of anterior pituitary function.

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Laser-induced fluorescence and fluorescence microscopy for capillary electrophoresis zone detection

Cited by 117 publications

References 22 publications

Detection in capillary electrophoresis

Detection in capillary electrophoresis

Biomedical applications of capillary electrophoresis with laser‐induced fluorescence detection

Serial Long-Term Assessment of in vivo LHRH Release from a Discrete Area of the Ewe Median Eminence Using Multiple Guide Cannula Assembly and Removable Push-Pull Cannulae

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