HIGH-PRESSURE STOPPED-FLOW SPECTROMETER FOR KINETIC-STUDIES OF FAST REACTIONS BY ABSORBENCY AND FLUORESCENCE DETECTION

The development of a stopped-flow instrument that operates over a temp erature range of -40 to +100 degrees C and up to 200 MPa is described, The system has been designed so that measurements can be performed in absorbance and fluorescence modes simultaneously, without dismantling the unit. It can easily be combined with an optical system of a conve ntional ambient pressure setup by using light guides, Optimum optical performance and a wide operating wavelength range (220-850 nm) are ach ieved as the Light is not passing through the pressurizing fluid, A sp ecial design for the pistons has been developed; thus, the apparatus h as proven to be leak-free, even under extreme conditions (high pressur e, low temperature, various solvents). The dead time of the system is found to be less than 2 ms at 298 K and is pressure independent up to 200 MPa, We examined the kinetics for the formation of the Mg2+-8-hydr oxyquinoline chelate in aqueous solutions at pH 8.0 in order to develo p a convenient alternative test method for high-pressure stopped-flow spectrometers with absorption and fluorescence detection.