set of parameters has to be found empirically for each individual system and the skilled man will be able to find these parameters without inventive work the flow pulse at the higher flow rate is maintained until a preselected signal value from the reaction response has been recorded e g a peak maximum and at this point the flow will be decreased by a return to normal flow command to the pump 10 thereby stopping the additional flow of buffer solution the duration of the pulse of increased flow rate may be 10 60 s preferably 20 40 s temperature fluctuations may be eliminated by thermostating the system e g having the er 26 immersed in a controlled temperature bath fig4 illustrates the control algorithm in a simplified flow chart form when it is desired to make a measurement the operator may select a inject command from a menu or the computer may be programmed to issue the command at a preselected point in time this command will set the valve such that the flow of sample blood is diverted into the buffer flow for a time sufficient to inject the desired sample volume i e 10 u03bcl then the valve is reset to normal mode i e the.