From Tables to Visuals: Principal Component Analysis, Part 2
February 1st 2005The second part in this series focuses on the variables in large data tables, looking at the vocabulary used by PCA experts, and explaining some of the background to the method. It further provides practical examples of how these variables operate in practice.
Flow, Pressure, and Temperature Calibration: Part II
January 1st 2005In last month's installment of "GC Connections," John Hinshaw discussed how peak retention times depend upon relationships between pressure, flow rate, oven temperature, column dimensions, and stationary phase. This concluding installment of a two-part series discusses the effects that column variability has on isothermal capillary gas chromatography and explores instrument calibration with the goal of maximizing instrument-to-instrument similarity of retention times.