Detection dopamin

Detection of the molecules produced, consumed, and secreted by the cells described here is challenging for two main reasons. First, the cell is dynamic and constantly tries to maintain balance. As such, molecules concentrations or speciation are usually changing. Second, the matrix in which these measurements are typically performed is very complex. Thus, the technique of choice needs to have some built-in feature that enables the analyst to overcome the matrix. To date, a variety of measurements have been employed to learn more about the roles of the cells in the microcirculation. Specifically, fluorescence, chemiluminescence, and amperometry have all been used extensively. Not surprisingly, all three of these detection schemes are readily employed in capillary electrophoresis-based determinations. Therefore, many of the measurements employ technology from the CE field. However, due to the cell matrix complexity, techniques are required to overcome potential interfer-ents. Eor example, Kovarik et al. employed a Nafion coating over a micromolded ink electrode for selectivity in detecting dopamine in the presence of an anion interferent (ascorbate). Eor similar reasons, Ku" ° employed the classic method of multiple standard additions to quantitatively determine the amount of NO released from activated platelets in a flowing stream. 

The principle of detecting dopamine at the surface of a carhon fiber microelectrode and the view under a microscope of a detecUon experiment carried out on a single ceil... 

One of the earliest CNT-tipped biological sensor reported was an SWCNT-coated carbon fiber nanoelectrode (100-300 nm tip diameter, as shown in Figure 7.2b). Using cyclic voltammetry, the CNT-tipped electrode could detect dopamine, epinephrine, and norepinephrine at concentrations on an order of magnitude lower than noncoated probes. The demonstration was significant because the dimensions of the CNT-tipped probe would make it possible to study the functions of living cells and tissue with a minimal level of intrusion. Additionally, the pencil-like shape of the probe readily fits the standard ceU physiology equipment and facilitated its use. 

Voltammetric Approach for In-vivo Detecting Dopamine Level of Rat s Brain... 

Lyne PD, O Neill RD (1990) Stearate-modified carbon paste electrodes for detecting dopamine in vivo decrease in selectivity caused by lipids and other surface-active agents. Anal Chem 62 2347-2351... 

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