Articles by Richard Sheridan

The spectrophotometer is one of the most frequently used instruments for the identification of unknown chemical compounds, determination of enzymatic activity, analysis of chromatographic separations, and study of polymerization reactions. The sensitivity and performance of a given instrument depend on the quality and design of both the optical and the electronic components. In addition, today's sophisticated spectrophotometers are computer-controlled and thereby facilitate such studies as enzym

Analytical chemists are often faced with the task of separating complex chemical mixtures into pure chemical species that can then be precisely identified. To accomplish this task, scientists often use liquid chromatography (LC) or gas chromatography (GC) techniques followed by use of a variety of sophisticated spectroscopic detectors to analyze the purified compounds. At next month's Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, more than 800 companies will unveil a v

With the scanning electron microscope (SEM), scientists in a range of fields—from biology to materials science to microelectronics—can analyze the surface of objects with a resolution approaching molecular dimensions. Although conceptually developed in the 1940s, the SEM was not put into practical use until the 1960s. Improvements in SEM technology continue with the introduction this year of a device that can image unprepared specimens without contaminating the microscope or charg