Electrochemical detection pulsed

WR. LaCourse, Pulsed Electrochemical Detection in HPLC, Wiley, New York, 1997. 

Vandeberg, P. J. and Johnson, D. C., Pulsed electrochemical detection of cysteine, cystine, methionine, and glutathione at gold electrodes following their separation by liquid chromatography, Anal. Chem., 65, 2713, 1993. 

Kynaston, J. A., Fleming, S. C., Laker, M. F. and Pearson, A. D. J., Simultaneous quantification of mannitol, 3-O-methyl glucose and lactulose in urine by HPLC with pulsed electrochemical detection, for use in studies of intestinal permeability, Clin. Chem., 39, 453, 1993. 

Determination of iodo amino acids by HPLC with inductively coupled plasma (ICP)-MS detection had LOD 35-130 pg of I, which is about one order of magnitude lower than with UVD usually applied for these compounds175. Amino acids and peptides containing sulfur, such as cysteine, cystine, methionine and glutathione, can be determined after HPLC separation by pulsed electrochemical detection, using gold electrodes176. 

LaCourse, W. R., Pulsed Electrochemical Detection in High Performance Liquid Chromatography, Wiley, New York, 1997. The chapters on the various types of stripping with pulsed wave forms are very good. 

LaCourse WR, Dasenbrock CO. High-performance liquid chromatography pulsed electrochemical detection for the analysis of antibiotics. Advances in Chromatography 38, 189-232, 1998. 

Figure 25-23 Pulsed electrochemical detection of alcohols separated on Dionex AS-1 anion-exchange column with 0.05 M HCIOA. Peaks 1, glycerol 2, elhylene glycol 3, propylene glycol ...

Dennis Johnson and co-workers pioneered the area of pulsed electrochemical detection (PAD) [30,31]- In this technique, electrode fouling is circumvented through the use of a triple-pulse waveform. Alcohols, carbohydrates, amines, and sulfur compounds can all be detected using this technique. Alcohols and carbohydrates are determined by direct oxidation at the regenerated electrode surface, while amines and sulfur compounds undergo an oxide-catalyzed oxidation. 

Figure 27.16B shows the method known as pulsed coulometric detection (PCD). In this case, the current is integrated over a longer period and the time period is an integral number of 16.7-ms segments with typical total integration times of greater than 200 ms. The use of this type of waveform eliminates the most common electrical interference (60 Hz sinusoidal) encountered in pulsed electrochemical detection, and thereby increases the detection limits for most compounds. 

E Le Fur, PX Etievant, JM Meunier. Interest of pulsed electrochemical detection for the analysis of flavor-active alcohols separated by liquid chromatography. J Agric Food Chem 42 320-326, 1994. 

W.R. LaCourse and S.J. Modi, Microelectrode applications of pulsed electrochemical detection, Electroanalysis, 17 (2005) 1141-1152. 

C.D. Garcia and C.S. Henry, Coupling capillary electrophoresis and pulsed electrochemical detection, Electroanalysis, 17 (2005) 1125-1131. J. Wang, R. Polsky, B. Tian and M.P. Chatrathi, Voltammetry on microfluidic chip platforms, Anal. Chem., 72 (2000) 5285-5289. 

C.D. Garcia and C.S. Henry, Direct detection of renal function markers using microchip CE with pulsed electrochemical detection, Analyst, 129... 

Manyanga, V. et al. Improved hquid chromatographic method with pulsed electrochemical detection for the analysis of gentamicin, J. Chromatogr. A. 2008, 1189, 347-354. 

Separations of antibiotics were studied thoroughly. An IPC method using per-fluorocarboxylic acids as IPRs and pulsed electrochemical detection was devised to analyze gentamicin and performed better than the official method prescribed by the European Pharmacopoeia [78]. 

Zawilla, N.H., Li, B., Hoogmartens, J., Adams, E. Improved reversed-phase liquid chromatographic method combined with pulsed electrochemical detection for the analysis of amikacin. J. Pharm. Biomed. Anal. 43, 168-173 (2007)... 

La Course, W.R. Dasenbrock, C.O. Pulsed electrochemical detection of sulfur-containing antibiotics following high performance liquid chromatography. J. Pharm. Biomed. Anal. 1999, 19, 239-252. 

The most common electrode material used in LC-EC is carbon, either as solid glassy carbon disks in thin-layer cells, or as a high-surface-area porous matrix through which the mobile phase can flow. Gold electrodes are useful to support a mercury film and these are primarily used to determine thiols and disulfides, and also for carbohydrates using pulsed electrochemical detection... 

There are many substances which would appear to be good candidates for LC-EC from a thermodynamic point of view but which do not behave well due to kinetic limitations. Johnson and co-workers at Iowa State University used some fundamental ideas about electrocatalysis to revolutionize the determination of carbohydrates, nearly intractable substances which do not readily lend themselves to ultraviolet absorption (LC-UV), fluorescence (LC-F), or traditional DC amperometry (LC-EC) [2], At the time that this work began, the EC of carbohydrates was more or less relegated to refractive index detection (LC-RI) of microgram amounts. The importance of polysaccharides and glycoproteins, as well as traditional sugars, has focused a lot of attention on pulsed electrochemical detection (FED) methodology. The detection limits are not competitive with DC amperometry of more easily oxidized substances such as phenols and aromatic amines however, they are far superior to optical detection approaches. 

See, for example, W. LaCourse, Pulsed Electrochemical Detection in High-Performance Liquid Chromatography. New York Wiley, 1997 S. M. Lunte, C. E. Lunte, and P. T. Kissinger, in Laboratory Techniques in Electroanalytical Chemistiy 2nd ed P. T. Ki.ssin[Pg.692]

W.A. MacCrehan, R.A. Durst. Measurement of organomercury species in biological samples by liquid-chromatography with differential pulse electrochemical detection. Amt/ C/icm., 50,2108,1979. 

Campbell, J.M. E.A. Flickinger G.C. Fahey, Jr. A comparative study of dietary fiber methodologies using pulsed electrochemical detection of monosaccharide constituents. Sem. Food Anal. 1997,2, 43-53. 

MacCrehan and Durst (1978) developed a method for the determination of methyl-, ethyl-, and phenylmercury, based on reverse phase LC and differential pulse electrochemical detection. Fish samples were analyzed after alkaline hydrolysis, acidification with hydrochloric acid, and extraction into toluene. A detection limit of 2 /result obtained for a reference sample (NIST RM-50 Albacore tuna), 0.93 mg/kg, was in very close agreement to the certified total mercury level. Lajunen et al. (1984) and... 

La Course WR and Owens GS (1996) Pulse electrochemical detection of non chromophoric compounds following capillary electrophoresis. Electrophoresis 17 310-318. 

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