“…A flow method was chosen for calibration of the FID (6) and a special micropump was designed and built for this purpose (5, 62). A flow calibration method minimizes wall adsorption, which frequently can cause serious errors 'in other calibration techniques, such as exponential dilution (29, 40), direct injection (43,45), and diffusion cell procedures (2,29). Additionally, concentration changes can be made rapidly.…”