Series 4060 | Operational Theory | |
|
|
|
Operational Theory
2.1 Introduction
Series 4060 Analyzer for Benzene uses a FID detector and a Gas Chromatograph (GC) Column. Using a carrier gas and a microprocessor actuated switching valve, a fixed volume of sample is pushed into the Column maintained at a constant temperature. The eluted gas is analyzed for benzene in a FID detector and the column is back flushed to accept the fresh sample in the next cycle. Actual separating and detecting sequence may vary depending on compounds of interest in the application for which the analyzer is configured.
The Series 4060 Analyzer uses a flame ionization detector to sense benzene. The FID was selected based on the positive performance and extensive experience in the use of this detector in other Teledyne analyzers namely Model 402R and Model 4020. The FID has proven itself to be a rugged, stable, long life sensor giving years of trouble free operation in various applications. Also considering the fact that the required sensitivity of 100 ppb full scale was achieved, FID was considered a better choice over the limited life and less reliable Photo Ionization Detector.
A stainless steel packed column containing Chromosorb Diatomite was used at a constant temperature of 70 C. Using nitrogen as a carrier gas and a 5 ml sample loop, benzene elutes from the column within a few minutes. Additionally, a clear separation is observed from other aromatic hydrocarbons, namely toluene, ethyl benzene, and xylenes. The actual temperature setpoint and compound separation for your instrument may be different depending on the application. It is listed in the Addendum and Testing Results section of Appendix B.
2.2 Modes of Operation
The analyzer has 2 modes of operation depending on the position of the GC Sampling Valve (See Piping Diagram in Figure
Teledyne Analytical Instruments | 19 |