Patent ID: 7810371
Filing Date: 2010-10-12
Classification: B01L,G01F,G01N

Abstract:
1. A process for calibrating and/or equilibrating single-channel and multi-channel liquid handling devices in which a dispensing volume of a liquid is dispensed in a measurement chamber of a measurement chamber carrier via dispensing channel(s) of the liquid handling device, each measurement chamber being associated with a dispensing channel, and the dispensing volumes which correspond in each instance to an actual volume are determined in the individual measurement chambers and compared to a reference volume and/or to one another in order to change device parameters influencing the respective dispensing volume in the event of deviations beyond a predetermined tolerance limit, comprising the following process steps: generating an operating pressure in a pressure chamber whose volume is known; hermetically sealing an unfilled measurement chamber and connecting the measurement chamber to the pressure chamber; measuring the chamber pressure, which is now equal to a first equilibrium pressure that has undergone a pressure change relative to the operating pressure depending on the measurement chamber volume; storing the first equilibrium pressure associated with this measurement chamber; opening the measurement chamber and repeating the preceding process steps depending on the quantity of additional measurement chambers in the measurement chamber carrier; filling the measurement chambers by dispensing a liquid via the dispensing channels of the liquid handling device; generating the operating pressure in the pressure chamber; hermetically sealing a measurement chamber and connecting this measurement chamber to the pressure chamber; measuring the chamber pressure, which is now equal to a second equilibrium pressure that has undergone a pressure change relative to the operating pressure depending on the difference between the measurement chamber volume and the liquid volume; storing the second equilibrium pressure associated with this measurement chamber; opening the measurement chamber and repeating the preceding three process steps depending on the quantity of additional measurement chambers in the measurement chamber carrier; determining difference values between the first and second equilibrium pressures associated in each instance with a measurement chamber; associating individual actual volume values with the individual difference values using the thermal equation of states of ideal gases p·V=n·R·T, where p is pressure, V is volume, T is temperature, and R is the universal gas constant, and the proposition that the amount of gas in the system before and after the pressure equilibrium is constant, i.e., the amount of gas in the measurement chamber plus the amount in the pressure chamber is equal to the amount in the pressure chamber and measurement chamber after equilibrium; comparing these actual volume values in each instance to a value for a reference volume and/or to one another; and changing the device parameters of the liquid handling device influencing the dispensing volumes are changed in the event of deviations of the actual volume values from the value for the reference volume or from one another beyond a predetermined tolerance and, if necessary, repeating the preceding process steps beginning with the filling of the measurement chambers.