A new portable centrifugal analyzer with expanded versatility.

New developments in solid-state electronics applied to the Centrifugal Fast Analyzer have resulted in a prototype portable instrument with several unique improvements, yielding expanded analytical versatility and the capability to operate from 110 V ac or a rechargeable battery pack. The analyzer, contained in an 47 X 28 X 30 cm box and weighing 25.4 kg, utilizes a self-contained microprocessor to control some analyzerfunctions as well as to perform data acquisition and analysis. Hardcopy output is produced by an integral thermal printer. Several analysis options are available, including determination of reaction rate. by linear regression analysis. Temperature is controlled at one of three set points (25, 30, or 37 #{176}C) by means of a thermoelectric heat pump located in the rotor holder. A clutchbrake assembly incorporated in the rotor-drive system enables the rotor to be accelerated to 80% of run speed within 100 ms. Utilization of a parallel-channel rotor and a high-resolution, 2 MHz clock enables reactions to be monitored within 100 ms of solution transfer. A maximum of 99 observations may be acquired at variable intervals, the minimum being one observation per revolution at 4000 rpm (one observation consists of measurements of dark current and transmission or fluorescence signals from 17 cuvets). The drive system, rotor speed, and the clutchbrake are controlled by the microprocessor and automatically synchronized with data acquisition. Other analyzer operations currently under control of the microprocessor include the selection of preamplifier gain, transmission filters, and primary and secondary filters for fluorescence. The system is described and its various analytical capabilities are evaluated.