Recovery of voltammograms by target factor analysis of current-time data in electrochemical detection

Carbon-fiber microelectrodes are frequently used as chemical sensors in biological preparations. In this work, we evaluated the ability of cyclic voltammograms recorded at fast-scan rates to resolve neurochemicals when analyzed by principal component regression. A calibration set of 30 cyclic voltammograms was constructed from 9 different substances at a variety of concentrations. The set was reduced by principal component analysis, and it was found that 99.5% of the variance in the data could be captured with five principal components. This set was used to evaluate cyclic voltammograms obtained with one or two compounds present in solution. In most cases, satisfactory predictions of the identity and concentration of analytes were obtained. Chemical dynamics were also resolved from a set of fast-scan cyclic voltammograms obtained with the electrode implanted in a region of a brain slice that contains dopaminergic terminals. Following stimulation, principal component regression of the data resolved the changes in dopamine and pH that were evoked. In a second test of the method, vesicular release was measured from adrenal medullary cells and the data were evaluated with a calibration set composed of epinephrine and norepinephrine. Cells that secreted one or the other were identified. Overall, the results show that principal component regression with appropriate calibration data allows resolution of substances that give overlapping cyclic voltammograms.

show abstract

“…In a previous report on the use of PCA to evaluate electrochemical responses, the data were not background subtracted …”

Section: Resultsmentioning

confidence: 99%

Resolving Neurotransmitters Detected by Fast-Scan Cyclic Voltammetry

Johnson²,

2004

View full text Add to dashboard Cite

show abstract

“…PCR has been used to remove the background from cyclic voltammograms . Previously, this approach did not improve our results because the background signal dwarfed the faradaic signals .…”

Section: Resultsmentioning

confidence: 99%

Dopamine Detection with Fast-Scan Cyclic Voltammetry Used with Analog Background Subtraction

et al. 2008

View full text Add to dashboard Cite

Fast-scan cyclic voltammetry has been used in a variety of applications and has been shown to be especially useful to monitor chemical fluctuations of neurotransmitters such as dopamine within the mammalian brain. A major limitation of this procedure, however, is the large amplitude of the background current relative to the currents for the solution species of interest. Furthermore, the background tends to drift, and this drift limits the use of digital background subtraction techniques to intervals less than 90 s before distortion of dopamine signals occurs. To minimize the impact of the background, a procedure termed analog background subtraction is reported here. The background is recorded, and its inverse is played back to the current transducer during data acquisition so that it cancels the background in subsequent scans. Background drift still occurs and is recorded, but its magnitude is small compared to the original background. This approach has two advantages. First it allows the use of higher gains in the current transducer, minimizing quantization noise. Second, because the background amplitude is greatly reduced, principal component regression could be used to separate the contributions from drift, dopamine, and pH when appropriate calibrations were performed. We demonstrate the use of this approach with several applications. First, transient dopamine fluctuations were monitored for 15 min in a flowing injection apparatus. Second, evoked release of dopamine was monitored for a similar period in the brain of an anesthetized rat. Third, dopamine was monitored in the brain of freely moving rats over a 30 min interval. By analyzing the fluctuations in each resolved component, we were able to show that cocaine causes significant fluctuations in dopamine concentration in the brain while those for the background and pH remain unchanged from their predrug value.

show abstract

“…As a result, the signal-to-noise ratio at the higher harmonics is increased and the sensitivity is improved. Long and Weber first used a large amplitude sine wave to simplify the process of Fourier transform digital filtering of voltammetric signals. − Unfortunately, the digital low-pass filter they implemented severely distorted the time domain signal once filtered, making it difficult to interpret the resulting voltammetry in the time domain.…”

mentioning

confidence: 99%

Detection of Native Amino Acids and Peptides Utilizing Sinusoidal Voltammetry

2000

View full text Add to dashboard Cite

Native amino acids and peptides were detected at a copper microelectrode using sinusoidal voltammetry (SV). Traditionally, these molecules can only be measured after derivatization with either a fluorescent or electroactive tag. In this work, an electrocatalytic oxidation reaction at copper is used to detect underivatized peptides and amino acids. The oxidation reaction is somewhat independent of peptide structure (i.e., it is not limited to the detection of aromatic amino acids) and is therefore able to produce nanomolar detection limits for all amino acids and peptides tested. A scanning technique, sinusoidal voltammetry, is used to provide the sensitivity of constant-potential techniques but also provide selectivity gained through utilization of the frequency domain. The frequency spectrum due to the oxidation of each molecule has a unique "fingerprint" response resulting from the kinetics of oxidation at the electrode surface. Through examination of the frequency spectra, even structurally similar molecules can be easily distinguished from one another. Flow injection analysis is used to demonstrate the sensitive and selective detection of a variety of amino acids and peptides. This technique can also be easily coupled to a separation step, i.e., high-performance liquid chromatography or capillary electrophoresis without electrode fouling from the adsorption of the analytes.

show abstract

Recovery of voltammograms by target factor analysis of current-time data in electrochemical detection

Cited by 3 publications

References 27 publications

Resolving Neurotransmitters Detected by Fast-Scan Cyclic Voltammetry

Resolving Neurotransmitters Detected by Fast-Scan Cyclic Voltammetry

Dopamine Detection with Fast-Scan Cyclic Voltammetry Used with Analog Background Subtraction

Detection of Native Amino Acids and Peptides Utilizing Sinusoidal Voltammetry

Contact Info

Product

Resources

About