An ASTM Standard Practice for Testing Fixed-Wavelength Photometric Detectors Used in Liquid Chromatography

Comparison of three- and five-micrometer column packings for reversed-phase liquid chromatography

“…The time constant for the combined detector-data system was estimated by sampling a steady detector signal at 20-ms intervals and then suddenly shifting the slightly loosened cell housing to effect an abrupt change in light intensity at the photodiode. Response times and time constants were calculated by using established formulas (26). This method, while perhaps crude, served to establish an upper bound for the time constant, r, of the detector data system combination of 76 ± 12 ms (mean and standard deviation of eight measurements).…”

Fundamental Relationships of Chromatography

“…The detector performance characteristics of interest to the chromatographer are sensitivity, minimum detectability, dynamic range, response linearity and noise characteristics [260][261][262][263][264][265][266][267][268][269][270][271][272]. Other properties of the detection system which indicate its suitability for a particular problem are flow sensitivity and response time.…”

“…It is convenient to divide Chromatographie detectors into two groups: concentration sensitive devices which respond to a change of mass per unit volume (g/ml) and mass sensitive devices which respond to a change in mass per unit time (g/s). Drift is the average slope of the noise envelope measured as the vertical displacement of the pen over a period of 1 h. For spectrophotometric detectors, the signal response is proportional to the path length of the cell and noise values are normalized to a path length of 1 cm [271]. For a concentration sensitive detector it is given by S = AF/w and for a mass sensitive detector by S = A/w, where S is the sensitivity, A the peak area, F the flow rate through the detector, and w the sample amount.…”