Mark R. Glick

A Comprehensive Table of Atomic Fluorescence Detection Limits and Experimental Conditions

A comprehensive table of atomic fluorescence spectrometry results has been compiled and arranged by element. Data tabulated include excitation and fluorescence wavelengths, atom reservoir, excitation source, limits of detection, and comments concerning experimental peculiarities and types of samples analyzed.

Sensitive, indirect photometric detector for high-performance liquid chromatography using a light-emitting diode

A low-noise detector for indirect photometric detection has been constructed using a highly stable source--a light-emitting diode (LED). Use of the detector is demonstrated for reversed-phase liquid chromatography by adding methylene blue to the mobile phase to make a background signal. The indirect determination of alcohols by their effect on methylene blue concentration distribution is demonstrated, and an investigation is made into the conditions for high sensitivity. Because the source exhibits low noise, the detection limits for alcohols are as low as more complex and expensive detection methods, despite the lower radiant power of the LED. Detection limits for nine alcohols are below micrograms injected amounts.

Molecular Absorption Measurements by FT/UV-Vis Spectrometry

Fourier transform spectrometry in the UV-Vis region (FT/UV-Vis), because it is source shot-noise limited, has a signal-to-noise ratio (S/N) disadvantage in comparison to dispersive spectrometry, especially with dense spectra. At the expense of poorer S/N, FT/UV-Vis can be satisfactory for high-resolution measurements. However, low-resolution spectroscopic studies, such as molecular absorption measurements, are not expected to be performed advantageously by FT/UV-Vis. The broad, dense spectra with high intensity throughout a wide spectral range should show a significant S/N degradation, in comparison to results with dispersive spectrometry. To investigate these expectations, we have used a Michelson interferometer to obtain low-resolution molecular absorption spectra of polycyclic aromatic hydrocarbons (PAHs).

Determination of Polycyclic Aromatic Hydrocarbons in Cooked Beef by Low-Temperature Molecular Luminescence Spectrometry Using a Moving Sample Cooling Belt

Four polycyclic aromatic hydrocarbons are identified in broiled hamburger at the part per billion level by low-temperature molecular luminescence spectrometry (LT-MLS). Hamburger extracts in a Shpolskii solvent are injected onto a moving sample cooling device maintained at 15 K in a vacuum. Results obtained by the present system are compared with those obtained by constant energy synchronous luminescence spectrometry (CESLS) at 77 K and by high-performance liquid chromatography (HPLC) with multiwavelength detection.

Fourier transform u.v.-visible molecular luminescence spectrometry: Fluorescence excitation spectra

Abstract The analytical utility of Fourier transform spectrometry in the u.v.-vis region was investigated. Molecular fluorescence excitation spectra were acquired for four polycyclic aromatic hydrocarbons frozen in Shpolskii solvents. Analytical figures of merit were determined for coronene, including a limit of detection of 2 ppb and a precision better than 13% RSD. The major sources of noise in FT/u.v. molecular fluorescence spectrometry are discussed, and results are compared to those reported earlier from wavelength dispersive instruments.

Design of a Modular, Multiwavelength Fluorescence Detector for Liquid Chromatography

ABSTRACT A modular fluorescence detector with computer data acquisition has been designed and built for high-performance liquid chromatography (HPLC). The modular approach provides selectivity that rivals array-based detectors, and the use of photomultiplier tubes gives sensitivity that surpasses them. Up to three modules can be connected, each adding one excitation wavelength and four emission wavelengths. An Apple microcomputer is used for acquisition and analysis of the twelve channels of data.

Jim Winefordner: Thirty Years of Teaching and Research at the University of Florida

For 30 years Jim Winefordner has been teaching and researching at the University of Florida in Gainesville. During that time he has made significant contributions in many areas of optical analytical spectroscopy, from atomic fluorescence spectrometry to molecular phosphorimetry, and he has guided the research of hundreds of graduate students and postdoctoral workers. He continues to teach undergraduates every years, as he has since 1959. Jim Winefordner is a leading proponent of fundamental physical approaches to analytical spectroscopy, a position that has marked his research since his earliest publications. In the mid-60s he introduced atomic fluorescence spectroscopy as an analytical method, and in the 80s he continues to extend the boundaries of modern analytical spectroscopy. A prolific scientist and a dedicated teacher, Jim has made his mark in almost all areas of analytical spectroscopy, and he has personally influenced the lives of many young scientists.