Automated Volume Verification for Quality Control

Accurate measurement and transfer of small volumes of liquids are crucial aspects of life science research. The working principle is simple: a set volume of liquid is determined to be pipetted, then aspirated, and dispensed. Unfortunately, whether it be manual or automated pipetting, errors are common involving techniques for the former, and parameters such as the liquid class, chemical nature, instrument compliance, and environmental conditions for the latter.

As the handling and transfer of liquids are essential for assay reproducibility and validity, it is equally important to verify one’s pipettes are precisely transferring the desired volumes. Life science labs require volume verification for accuracy and quality control, especially in scenarios where science transforms into a manufacturing workflow and studies are done in bulk. Here, volume verification becomes essential and helps assure the quality and credibility of experimental results.

VOLUME VERIFICATION – WHY IS IT IMPORTANT?

With the rise of genomics, the ability to miniaturize reagents has made everything, such as tubes, plates, etc., smaller while increasing throughput. As such, being able to measure volumes quickly and accurately across many samples is critical for diverse users including diagnostic labs, reagent and reagent kit manufacturers, nucleic acid synthesis groups, or DNA primer companies. Volume verification is also important for inventory management by compound storage labs and biobanks.

Manual/visual/pressure-based forms of volume verification involve checking a single tip at a time. This is not sustainable, lacks accuracy, and can take too much time. Gravimetric methods use a balance to weigh the transferred liquid and work best for measuring single-channel devices and larger liquid volumes between 20 to 1000 μL but lack single well resolution. Other vision control/light-based pulse methods, such as fluorometry, single dye photometry, and ratiometric photometry, also suffer from a lack of accuracy, inability to measure either very small or very large volumes, traceability, and are time intensive.

BIOMICROLAB VC384 – THE ORIGIN STORY

SPT Labtech’s BioMicroLab (BML) was motivated to meet this challenge, specifically focusing on plate-based volume verification solutions. To eliminate time-consuming visual and manual volume inspection tasks, BML explored automated alternatives with lab automation taking off across a large variety of applications, amid requirements for higher sample volumes, efficiencies, and throughput in research labs around the world. The benefits of integrated volume verification stem from an ability to streamline and simplify quality control within an overall automated workflow. Initial testing led to ultrasonic technologies being deemed the ideal fit. A single sensor was found viable for 96 well plate diameters.

This would help in the development of BML’s VolumeCheck (VC) 100, an innovative and automated solution for laboratories requiring integrated detection of low or high volumes in uncapped 96, 48, and 24-format well plates and tube racks in their workflow. Moving forward, BML would expand the VC100’s abilities, with the help of an ultrasonic engineer (a Russian submarine engineer specializing in underwater ultrasonics), by manually adjusting the system sensor to fit smaller size 384 well plate diameters. Further refinement of this process in manufacturing led to the creation of the BML VC384.

BML VOLUMECHECK 384

The BML VC384 is the preferred non-contact volume verification system for most laboratories and offers highly accurate, automated volume verification that is also compatible with standard labware. The working principle of the VC384 involves an ultrasonic sensor that sends a pulse down to the meniscus, helping measure the sensor to sample liquid distance in a tube or well. Liquid volumes are then determined from the distance measured alongside the calibration curve for the relevant liquid type and labware. The creation of the calibration curves themselves requires knowledge of the intended volumes, labware, and liquid types utilized in a study.

In this manner, the VC384 can measure unknown sample volumes in well plates and test tubes while accounting for reliable volume readings. The VC384 is a benchtop device that can be connected to a Windows 7/8/10 PC via a USB connection. A control program on the PC enables the instrument and organizes data collected by the VC sensor, which maintains high quality precision and accuracy across labware cohorts. Most variations concerning the sensor were observed near the bottom and transition point of a tube or well.

MOVING FORWARD

Volume verification will remain a persistent endeavor for future labs as data aggregation is a fundamental tenet of scientific research. Quality control of process-level data from volume checking and instrument input/output feeds back into the data driven technology pipeline that is modern life science research. Automation in liquid handling and volume verification greatly enhances user experience and laboratory throughput while minimizing time-consuming tasks. SPT Labtech's BML VC384 is representative of this objective. By properly characterizing the selected labware with the corresponding calibration curve fit, the VC384 assists users in getting accurate readings during sample runs. Being able to detect consistently down to 500 nL of sample volumes in specific labware, the VC384 provides impressive resolution for potential workflow applications and is the ideal volume verification system.

To learn more about the BML VC384, visit: bit.ly/3QwSl9Z