John G. Nikelly, PhD
John G. Nikelly
Professor
Ph.D., Analytical Chemistry
Cornell University, 1956
Medicinal/Pharmaceutical Chemistry
Analytical Chemistry
Pharmaceutical Chemistry
McNeill 221
(215) 596-8848
j.nikell@usp.edu
Research Interests
- The use of parallel columns in gas chromatography
- Pharmaceutical analysis by GC and HPLC
- Indirect detection of UV-transparent compounds
Research Summary
The components in a mixture may be identified by gas chromatographic retention times, but this normally requires making runs on two different columns. Alternatively, the analysis could be done in a single run on two columns, but this requires the use of two detectors. We are developing a system of parallel columns including a retention gap that makes possible identification with a single injection and single detector resulting in two consecutive gas chromatograms.
The UV detector is by far the most common type used in HPLC. However, there are many compounds, such as ethanol and water, that are UV-transparent and thus cannot be determined by HPLC with UV detection. We have developed an indirect photometric detection technique for determining ethanol, and are currently working on a similar technique for determining water.(Indirect photometric detection involves the adding of a UV-absorbing component in the mobile phase and measuring the resulting "system peaks".)
Recent or Representative Publications
“Chiral Separation of Labetalol Stereoisomers in Human Plasma by Capillary Electrophoresis,” T. V. Goel, J. G. Nikelly, R. C. Simpson, and B. K. Matuszewski, J. Chromatogr. A, 2004, 1027 (1–2), 213.
“Metabolism of para-aminophenol by rat hepatocytes,” Z. M. Yan, J. G. Nikelly, L. Killmer, and J. B. Tarloff, Drug Metabolism and Disposition, 2000, 28(8), 880.
“The Use of Precolumns for Solvent Focusing in Capillary Column Gas-Chromatography,” Z. M. Yan and J. G. Nikelly, J. High Resol. Chromatog., 1994, 17, 522.
“A Solution to Split Peaks in LC,” J. G. Nikelly, J. High Resol. Chromatog., 1994, 17, 54.