Continuous in vivo Monitoring of Blood Diffusible Calcium Using On-line Microdialysis Sampling Coupled with Flame Atomic Absorption Spectrometry

Tseng, Wei-Chang; Sun, Yuh‐Chang; Lee, Cheng-Fa; Yang, Mo‐Hsiung; Huang, Yeou‐Lih

doi:10.2116/analsci.21.225

Cited by 10 publications

(3 citation statements)

References 23 publications

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“…With SPME, the concentration of free analyte is determined by calibration against buffer or protein-free plasma (22 ). Nevertheless, the total concentration can be determined as well by in vitro calibration against whole blood incubated with 10% CO 2 (Fig. 2) (17 ).…”

Section: Resultsmentioning

confidence: 99%

“…Current techniques that are applicable for in vivo analysis include microdialysis, ultrafiltration, solid-phase microextraction (SPME), 1 sensors and sensor arrays, microfluidics, and nanotechnology (1 ). Although microdialysis has numerous in vivo applications (2)(3)(4)(5), it has many problems, the most important of which are the loss of perfusion fluid and the difficulty in obtaining reliable quantitative data (6 ). Ultrafiltration avoids time-consuming recovery calculations (7 ), but the membranes are prone to clogging, and the method is not suitable for compounds that are highly bound to plasma proteins.…”

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confidence: 99%

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Fast In Vivo Microextraction: A New Tool for Clinical Analysis

Musteata

Pawliszyn³

2006

Clinical Chemistry

104

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Background:We sought to develop a technique with the potential to partly replace current methods of analysis based on blood draws. To achieve this goal, we developed an in vivo microextraction technique that is faster than conventional methods, interferes minimally with the investigated system, minimizes errors associated with sample preparation, and limits exposure to hazardous biological samples. Methods: Solid-phase microextraction devices based on hydrophilic polypyrrole and polyethylene glycol coatings were used for direct extraction of drugs from the flowing blood of beagle dogs, over a period of 8 h. The drugs extracted on the probes were subsequently quantified by liquid chromatography coupled to tandem mass spectrometry. Two calibration strategies-external and standard on the fiber-were used to correlate the amount extracted with the in vivo concentration. Results: Diazepam and its metabolites were successfully monitored over the course of a pharmacokinetic study, repeated 3 times on 3 beagles. The fast microextraction technique was validated by comparison with conventional plasma analysis, and a correlation factor of 0.99 was obtained. In addition to total concentrations, the method was useful for determining free drug concentrations. Conclusions:The proposed technique has several advantages and is suitable for fast clinical analyses. This approach could be used not only for drugs, but for any other endogenous or exogenous compounds.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Fast In Vivo Microextraction: A New Tool for Clinical Analysis

Musteata

Pawliszyn³

2006

Clinical Chemistry

104

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“…To date, there have been two studies of off-line ETAAS , coupled with MD and several reports of on-line MD coupled with flame AAS (FAAS) , and ETAAS − to monitor the dynamic changes of Ca and Mg in the blood of rabbits and Mn, Zn, and Mg in the brain of an anesthetized rat. In these studies, the salty matrixes were previously eliminated by adjusting the temperature program and choosing a suitable matrix modifier, such as ammonium nitrate.…”

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confidence: 99%

In Vivo Monitoring of Multiple Trace Metals in the Brain Extracellular Fluid of Anesthetized Rats by Microdialysis−Membrane Desalter−ICPMS

et al. 2007

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We have developed an on-line analytical system involving microdialysis (MD) sampling, a carbohydrate membrane desalter (CMD), and an inductively coupled plasma mass spectrometer (ICPMS) system for the simultaneous determination of multiple trace metals in the extracellular fluid (ECF) in the brains of anesthetized rats. The microdialysate that perfused from the animal at a flow rate of 0.5 microL/min was on-line transferred to the CMD to remove the high-sodium matrix, followed by ICPMS measurement. The role of the CMD in this on-line system was investigated in detail. With prior addition of EDTA to the microdialysate to form anionic complexes of the metal analytes and the use of NH4Cl as a regenerant to exchange Na(+) with NH4(+) ions, both quantitative recovery of the trace metal analytes and quantitative removal of the sodium matrix could be achieved. Two experimental modes of the monitoring system were constructed. For those metals (e.g., Cu, Zn, and Mn) that existed at (sub)nanogram-per-milliliter concentrations in the microdialysate, the temporal resolution was 10 min when using a 10 microL loop for sample collection, followed by CMD and ICPMS; for those elements (e.g., Ca and Mg) that existed at microgram-per-milliliter levels (or greater), near-real-time analysis was possible because the microdialysate could be led, bypassing the sample loop, directly to the CMD for desalting without any time delay. Further improvement of the temporal resolution for the low-concentration elements was not possible without decreasing the detection limits of mass detection. Among the eight trace metals tested using this on-line system, the method detection limits for Cu, Zn, Mn, Co, Ni, and Pb reached subnanogram-per-milliliter levels; for electrolyte species such as Ca and Mg, the detection limits were in the range of 50-100 ng/mL. Analytical accuracy, expressed as spike recovery, was 100% +/- 15% for all of the elements tested. We demonstrate the applicability of the proposed system through the successful measurement of the basal values of Ca, Mg, Cu, Zn, and Mn in the ECF of a living rat brain and through in vivo monitoring of the concentration profiles of Mn and Pt in the ECF after the injection of drugs (MnCl2 and cisplatin) into the rats. This microdialysis system is the first to offer real-time, in vivo monitoring of trace elements such as Ca and Mg.

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In vivomonitoring of the transfer kinetics of trace elements in animal brains with hyphenated inductively coupled plasma mass spectrometry techniques

Su¹,

Sun²,

Tzeng³

et al. 2009

Mass Spectrom. Rev.

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The roles of metal ions to sustain normal function and to cause dysfunction of neurological systems have been confirmed by various studies. However, because of the lack of adequate analytical method to monitor the transfer kinetics of metal ions in the brain of a living animal, research on the physiopathological roles of metal ions in the CNS remains in its early stages and more analytical efforts are still needed. To explicitly model the possible links between metal ions and physiopathological alterations, it is essential to develop in vivo monitoring techniques that can bridge the gap between metalloneurochemistry and neurophysiopathology. Although inductively coupled plasma mass spectrometry (ICP-MS) is a very powerful technique for multiple trace element analyses, when dealing with chemically complex microdialysis samples, the detection capability is largely limited by instrumental sensitivity, selectivity, and contamination that arise from the experimental procedure. As a result, in recent years several high efficient and clean on-line sample pretreatment systems have been developed and combined with microdialysis and ICP-MS for the continuous and in vivo determination of the concentration-time profiles of metal ions in the extracellular space of rat brain. This article reviews the research relevant to the development of analytical techniques for the in vivo determination of dynamic variation in the concentration levels of metal ions in a living animal.

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Continuous in vivo Monitoring of Blood Diffusible Calcium Using On-line Microdialysis Sampling Coupled with Flame Atomic Absorption Spectrometry

Cited by 10 publications

References 23 publications

Fast In Vivo Microextraction: A New Tool for Clinical Analysis

Fast In Vivo Microextraction: A New Tool for Clinical Analysis

In Vivo Monitoring of Multiple Trace Metals in the Brain Extracellular Fluid of Anesthetized Rats by Microdialysis−Membrane Desalter−ICPMS

In vivomonitoring of the transfer kinetics of trace elements in animal brains with hyphenated inductively coupled plasma mass spectrometry techniques

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