(1248-A) Comparative Analysis of Gravimetric Technology with Checkit®Go - Capillary Technology for Measuring Dispense Volumes in ALHS

Abstract: Ownership of Automated Liquid Handling Systems (ALHS) has increased in the last two years creating a demand for technologies to validate the accuracy of volumes dispensed by ALHS. Two common ways to check volume accuracy in ALHS are gravimetric and colorimetric methods. The classic gravimetric method measures the weight of the dispensed volume of the liquid using a high precision balance under strict environmental conditions (temperature, pressure, humidity), and then converted to obtain the dispensed volume. The colorimetric method measures the light absorption from a single dye or from dual dyes using a spectrophotometer and is then converted to the dispensed volume.
Both these methods are indirect with their measurements, requiring calibrated consumables and capital investments along with strict environmental conditions to be accurate. In addition, neither of these methods can use the sample solutions the robot will use in its daily operation, thus introducing errors caused by differences in viscosity and surface tension. The Checkit Go bypasses the above limitations by using capillary technology for volumetric measurements.
The Checkit® Go is an accurate, easy to use cartridge with precision capillaries for measuring the volume of liquid dispensed by ALHS. This microfluidic device with better than 2% accuracy, uses surface forces to draw dispensed liquid into 8 capillaries via capillary action, in just a few seconds. The user then either simply reads the volume of liquid in each capillary the same manner as reading a bulb thermometer against the graduations or uses the Checkit Recorder to capture, analyze and generate reports of the test. The Checkit Go has the footprint of standard microwell plates, and therefore the entire validation can happen on the robot bed offering convenience, portability and time savings. It is also compatible to work with most sample liquids, so viscosity and surface tension effects are included in the measurement. Being independent of the environmental factors, the validation results of ALHS obtained by Checkit Go at various geographical locations can be readily compared. Lastly, Checkit Go does not need instrumentation, maintenance, or personnel training.
Here, we compared results obtained from each step of validation by gravimetric and Checkit Go as stipulated by ISO 23783 -2 guidelines. The results confirm that the validation obtained using Checkit Go is comparable to the validation obtained by the classical gravimetric method.
Thus, Checkit Go is comparable to gravimetric method to validate the accuracy of ALHS with added advantages.