Automated pH Testing: Prioritizing Accuracy and Efficiency in the Lab

Life sciences research and diagnostics are generating more and more data every year by increasing throughput. Labs that don’t adapt are being left behind.

Manual pH testing is one of the most time-consuming and error-prone tasks at the bench. Between standardizing meters, equilibration time, and probe cleaning, testing even a handful of samples often requires a disproportionate amount of time to complete. This significant time requirement can also lead to measurement variability, particularly if samples can’t be tested simultaneously or by the same technician.

Automated pH meters have been developed specifically to address these pain points and decrease the workflow bottlenecks and errors associated with measuring pH in large numbers of samples. In doing so, labs of all sizes have increased data quality, compliance, and efficiency while benefiting from a rapid return on investment (ROI).

Recent technological advances and increased competition between automated lab equipment developers have elevated the quality and versatility of equipment while decreasing its price, making high-value, entry-level automated pH meters more accessible than ever.

Maximize efficiency and eliminate bottlenecks

Automating pH measurements has two primary effects in the Lab:

1) Improving the efficiency of lab staff

2) Increasing the overall productivity of the diagnostics or research program

pH measurement automation increases lab personnel efficiency directly by allowing staff members to delegate the monotonous, time-consuming task to an automated system. This frees up time for lab staff to perform other critical functions in the lab, including data analysis and reagent preparation. These are tasks that cannot be automated as easily. Lab staff are often more than happy to delegate these tedious lab responsibilities to robotic systems that aren’t prone to boredom or fatigue.

Automation can virtually eliminate the potential for pH measurement variability by performing all pH tests at the same time and in the exact same manner (Figure 1). While delegating monotonous tasks to inexperienced, less knowledgeable, and less expensive staffing options may seem attractive for some lab managers, variability or errors in pH measurements can quickly erase any perceived gains when experiments fail, or measurement variability masks subtle effects in an experiment.

Figure 1. Differences in day-to-day variability. The graphic on the left depicts large day-to-day variability between measurements versus the graphic on the right, which illustrates a smaller amount of day-to-day variability in measurements. https://www.itl.nist.gov/div898/handbook/mpc/section1/mpc114.htm

Automation enhances lab productivity by eliminating throughput bottlenecks, allowing the program to process and test more samples and generate more data. As life sciences diagnostics and research become increasingly high-throughput, cell culture, phenotyping, and drug discovery protocols often require automated assessments to efficiently determine pH at different time points during an assay.

Automated technologies have increased the potential throughput and overall productivity of labs worldwide; granting agencies are taking notice. Increased sample numbers enhance the statistical power of experiments, allowing researchers to uncover more subtle effects that might otherwise go undiscovered. Many granting agencies will prioritize funding for labs that integrate new technologies aimed at increasing research and diagnostic productivity and efficiency.

 

Improve data quality and compliance

Let’s face it: issues with data quality often stem from human error.

For example, failure to maintain and clean the electrode between samples can make pH readings susceptible to errors from contaminants and carryover from previous samples. Less-experienced technicians can also improperly calibrate manual pH meters or fail to calibrate them at all, resulting in inaccurate pH readings (Figure 2). Downstream lab personnel interpreting datapoints may not know how or if the pH meter was calibrated or cleaned properly when interpreting experiment results, which can compromise the accuracy of entire studies.

Figure 2. Inaccurate pH measurements are often caused by user error. https://blog.thermoworks.com/thermometer/ph-meter-care-and-common-mistakes/

Lab personnel can also get slow or inaccurate readings from a pH meter with a dried electrode. Distractions can cause technicians to leave the bench temporarily, only to come back to a pH meter with an electrode bulb that has been sitting out in the open for far too long. Rehydrating the electrode takes 15 minutes, if performed at all.

Automation can eliminate these user errors by consistently cleaning and air-drying the electrode between samples, calibrating the electrode, and storing the electrode bulb in the appropriate storage solution between measurement runs. As discussed in the previous section, automating pH testing additionally decreases measurement variability.

Additionally, some laboratory applications require compliance with FDA 21 CFR Part 11 to use electronic records and signatures to automate and streamline quality-control checks and ensure traceability. Many automated pH measurement systems offer equipment and software compliant with 21 CFR Part 11, including the entry-level Hudson Robotics Rapid_pH automated pH meter, making compliance reporting more effortless than ever before.

Weigh the costs and benefits of pH automation

High-throughput automation can prove highly beneficial to life sciences research and diagnostics. Unlike legacy testing equipment, automated testing equipment is designed to handle the large number of samples and constant measurement required for large-scale sample processing and assessment.

The most common barrier to automating pH measurements is the up-front cost of an automated system. Most lab managers and administrators, however, are surprised to learn how affordable and versatile an entry-level system can be, particularly for plate-based platforms. Entry-level systems have the added benefit of requiring few, if any, infrastructure changes as they typically sit on a laboratory bench away from high-traffic areas.

It is important for lab administrators to fully understand the long-term gains of automation in the lab before dismissing automated systems outright (Figure 3). While few studies outline exact dollar figures or payback periods to determine the ROI for various lab automation systems, platforms similarly improve the cost and time efficiency of clinical and research labs.

Histology labs that incorporate automation, for example, recover the upfront and any associated infrastructure costs of platforms by reducing the lab personnel costs required to complete a particular task, such as pH measurement. Whether these hours are eliminated from the lab budget or recovered by using those hours for other less routine tasks, the time and cost efficiency of the lab improves and productivity increases.

The second-way lab automation reduces costs is by virtually eliminating user error. More specifically, the standardization of measurements by automated platforms increases testing uniformity, reducing variability due to sampling variation between technicians and user error and fatigue. While figures don’t exist specifically for reduced error rates for automated pH measurements, automated bar coding and other workflow standardization in histology labs can decrease certain errors over 50% and slide errors up to 90%.

Figure 3. The ways that lab automation can improve efficiency and increase data quality in the laboratory.

Automation can also pay dividends in less tangible ways, such as shorter workflow cycles and protocol turnaround times. This can result in improved customer satisfaction and personnel productivity, more efficient research, and decreased consumable and reagent costs due to less waste associated with user error.

Estimate return on investment

One way to determine the cost-associated ROI over time is to estimate the amount of FTE saved by implementing lab automation platforms. By dividing the number of FTE required for testing by the volume of testing performed before and after lab automation (Figure 4), leadership can roughly estimate the payback period of a specific automation platform. As a reference, the Hudson Rapid_pH platform can test a single 96-well plate in between one hour and ten minutes and one hour and 45 minutes.

Figure 4. Comparing the personnel costs of testing per unit volume before (B) and after (A) lab automation.

Because personnel costs are one of the highest line items in any lab budget, any level of automation has the potential to reap significant overall savings. Histology labs, for example, have been able to reduce costs by as much as 8.8% per processed slide by integrating automation and modestly reducing consumable and reagent use. For instance, a $75,000 automated platform designed to label tubes has a payback period of only 2.8 years if one technician delegates the labeling of 400 tubes to the platform five days per week.

Additionally, automation can increase the amount of testing that occurs outside of normal working hours. For labs accustomed to processing and testing samples during the typical workday, automation can significantly increase data acquisition and productivity.

Consider pH automation options

Not every laboratory needs complete automation of a workflow or total automation of a lab, but managers and administrators often prefer lab equipment with the versatility to adapt to new and changing protocols and integrate with other systems over time.

Automated pH platforms are designed to complete the calibration, stabilization time, measurement, rinsing, drying, and recording of the sample pH result. Today, automated pH measurement platforms exist as a single, standalone machine or can be added as a function of an autosampling system with additional testing components and software. However, current autosampling systems work with much larger volumes than most high-throughput formats, limiting their practicality in many lab settings.

In contrast, systems that automate only pH measurement are designed around standard SBS (Society for Biomedical Sciences) sample plate sizes that are more compatible with high-throughput applications. The Hudson Rapid_pH, for instance, can adapt to measuring 24 to 96-well plates and volumes as low as 75 ml. The platform can also test samples in deep-well culture plates up to 50 mm in height.

Robotic pH measurement platforms can also be equipped with additional features depending on the requirements of a particular assay. Both autosampling systems and high-throughput automated pH meters can be fitted with unique pH probes explicitly designed for measuring more viscous samples and wash systems that can fully clean the probe between samples. A static wash well can also be added to systems where detergent washing or sterilization is required between measurements.

Protocols that require pH measurements at different temperatures (Figure 5) can also be accommodated by introducing a temperature-controlled heat block and temperature compensation software to the robotic platform. The Hudson Rapid_pH system additionally offers FDA CFR 21 Part 11 compliance software for labs that require electronic reporting.

Figure 5. Temperature-controlled heat block in a Hudson Robotics Rapid_pH automated laboratory pH meter. https://hudsonrobotics.com/ph-meters/benchtop-ph-meter/

Many manufacturers of lab automation solutions have designed an entire suite of products and software to automate common workflows in the lab. With increasing competition in the market, it is crucial to select lab equipment that can be paired with equipment solutions from other manufacturers when protocols change or additional automation is required. Lab automation scheduling software, such as Hudson Robotics SoftLinx, can interface with equipment from a variety of manufacturers to open and close microplate doors, run a particular protocol, check instrument status, read the run output, and make responses based on measurement results.

Lastly, automation equipment should be easy to use and require little training time: automated solutions are designed to save personnel time, after all. Companies selling automated lab equipment may be able to provide potential buyers with contact information for labs that have purchased and used their robotic lab solutions. Connecting with labs with similar workflows and integrated automated platforms can help managers better understand the pros and cons of using specific instruments at the bench.

High-throughput research and diagnostics are revolutionizing the life sciences and accelerating the speed of discovery. Automating routine tasks like pH measurement can benefit labs in various ways, including cost, time, and reagent savings and more consistent, higher quality data. Smaller labs have more high-value, entry-level options for lab automation than ever, and increased competition has made pricing much more competitive in the last decade. Much like natural selection, labs must choose to adapt or suffer the consequences in an increasingly competitive landscape.