ROBOTIC SAMPLE PREPARATION SCHEME FOR THE HPLC DETERMINATION OF NIFEDIPINE IN HUMAN BLOOD-PLASMA

An automated sample preparation and measurement system has been built using a laboratory robot and accessories for the determination of nife dipine in human blood plasma with HPLC. The system could perform rapid and accurate preparation and measurement of numerous samples with min imum human intervention. The automatic system executed each step of th e sample pretreatment (aliquoting of the sample, addition of internal standard, pH adjustment, liquid liquid extraction, phase separation, e vaporation to dryness and redissolution in eluent), injected the sampl es into an HPLC subsystem and recorded the chromatograms. A single ope ration, the centrifuging step of phase separation was carried out manu ally. Test results proved that this robotic sample preparation system is suitable to perform its task properly. The use of robot saves the a nalyst from the tiring, monotonous and sometimes dangerous manual labo ratory work and decreases the number of error sources. Another great a dvantage of the robot-system is that it can be easily transformed into similar type sample preparation systems with relatively little effort , since the existing subunits and operations can be recombined into ot her measuring formats by reprogramming the robot.