Automated Calibration and Analysis of VOCs with a Capillary Column Gas Chromatograph Equipped for Reduced Temperature Trapping

摘要

Recently an automated system for monitoring volatile organics by reduced temperature (-150C) preconcentration and capillary column/gas chromatographic analysis has been assembled and evaluated. The automation has now been extended to include multipoint calibration using single stage dilution of trace level organics with humidified zero air. Instructions for automation are carried out under microprocessor control on a Hewlett Packard Model 5880A gas chromatograph using a Basic language program to actuate external voltage outputs that set the electronic flow controllers and solenoid valves in the calibrator hardware. A sixteen-compound mixture of volatile organics has been used to demonstrate a five-point calibration. Data for each compound at each of five concentration levels are stored and used to obtain linear regressions, providing values of slope and intercept for the fit. The slopes are then entered manually via the HP 5880 keyboard into the calibration table. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy. Mention of trade names of commercial products does not constitute endorsement or recommendation for use.