PRECISION OF A DIODE-ARRAY SPECTROPHOTOMETER

Modern diode-array UV-visible spectrophotometers can record the entire spectrum of a sample in a fraction of a second. The operating procedure usually followed to obtain more reliable spectra involves scanning several spectra over a preset time Ti known as the integration time and averaging them. In order to establish how the selection of Ti and wavelength affect the repeatability and reproducibility of results, replicate spectra were recorded at different integration times and wavelengths. The results showed that both parameters influence the precision. The absorbance was also affected by Ti, to an extent that increased with decreasing wavelength. The best relative precision was accomplished over the absorbance range 0.8-1. © 1990.