This technical note documents the relationships between the different data paths and the conversion factors needed for different performance calculations for the Agilent 6890 Series gas chromatograph (GC) system, with particular emphasis on the calculation of minimum detection limits for the flame photometric detector (FPD) and the micro-electron capture detector (micro-ECD).
This document details the relationships between different data paths (GPIB, LAN, analog, INET) available for the Agilent 6890 Series gas chromatograph system. It focuses on calculating minimum detection limits (MDL) for the flame photometric detector (FPD) and the micro-electron capture detector (micro-ECD).
The text provides specific equations for MDL calculations in phosphorus and sulfur modes for the FPD, as well as for the micro-ECD. It further explains how to convert noise and area measurements to comparable units when using different data handling devices, such as the Agilent ChemStation or analog integrators, to ensure accurate performance comparisons.
| FPD Display Unit | 150 pA |
|---|---|
| Micro-ECD Display Unit | 1Hz |
| FID Display Unit | 1pA |
| NPD Display Unit | 1pA |
| ECD Display Unit | 5Hz |
The MDL is calculated using the equation MDL(P) = 2-N,-m,/A, where N is noise, m is the mass of phosphorus, and A is the integrated area.
The formula is MDL(S) = [2 -N/S,}2, which accounts for the squared dependence of the signal on sulfur concentration.