Handling of electronic absorption spectra with a desk top computer-I A fully automatic spectrophotometric titration...

A fully automatic system for combined spectrophotometric and pH titrations with on-line digital data acquisition is described for a Cary 118C spectrophotometer. The system consists of a temperature-controlled titration cell, a motor burette, a digital ph-meter, and an HP9820 desk-top computer. The computer controls the stepwise addition of reagent, the wavelength and paper drives, and the recorder pen; the absorption data and the pH-values are obtained on-line. A special interface was constructed from CMOS components. This is compatible with other computers or microprocessors having the necessary input/output facilities. The performance of the system has been tested critically. In 50 min more than 200 data points, each representing the mean of ten individual readings, can be collected, and the number of data points which can be obtained in one run is practically unlimited. The system avoids the cumbersome and error-prone manual handling of a large amount of data, it saves time, and, most important, the results have a high reproducibility.