Patent ID: 7297241

Claim:
A device for monitoring a microsample in a flow measuring cell of an analyzer comprising: at least one electrode system comprising at least two single electrodes positioned within said flow measuring cell, wherein said electrode system is configured for measurement of at least one substance contained in the microsample by application of a measurement voltage which is essentially a DC voltage, and detection of absence of bubbles and/or positioning of said microsample by application of an alternating voltage to said flow measuring cell, both the alternating voltage and the measurement voltage are simultaneously and directly applied to the single electrodes of the respective electrode system, and the measured AC component or the measured impedance provides a measure for the position of the microsample and/or the absence of bubbles; and a circuit for producing the voltages to be applied to the single electrodes, which circuit has a summation point at which the alternating voltage for the purpose of monitoring the microsample with regard to position and/or absence of bubbles is superposed on the DC voltage serving as measurement voltage.