LASER-BASED DOUBLE-BEAM ABSORPTION DETECTOR FOR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

The performance of a new double-beam absorption detector based on an all-electronic noise canceler was tested under HPLC conditions. The test compounds were chosen to be 2'-Cl-4-dimethylaminoazobenzene and 4'-Cl-4-di methylaminoazobenzene since they have absorption peaks in both the UV and the visible region. The major properties of the detector are discussed. The detector is linear through almost 4 orders of magnitude (10(5)-10(-9) M). The deviation between consecutive measurements is about 3% and the absorption noise level is 2. 10(-6) AU, which is lower by one order of magnitude compared to commercial absorption detectors.