Today it’s not uncommon for a food lab to use complex workflows that feature mass spectrometry (MS) and gas chromatography (GC) working in tandem to dramatically increase selectivity and sensitivity. And the more complex the workflow, the more reasons to automate the workflow and integrate the lab’s instruments with the LIMS, allowing data defensibility to rest in an automated process, and eliminating the errors that can result from manual data handling.
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Explore This IssueAugust/September 2015
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Case Study: Strawberry Jam and GC-MS/MS
For pesticides, many regulations set maximum residue levels (MRLs) at extremely low levels. Many of these MRLs are set at a default value of 0.01 milligram (mg)/kilogram (kg), which is the typical limit of determination of routine analytical methods. This means that some laboratories must test a wide array of foods for a large number of pesticides at concentrations at or below 0.01 mg/kg, doing so with low costs and fast turnaround times.
So let’s say that you wanted to test strawberry jam for pesticides. Once you extract the sample and prepare it according to a detailed sample prep workflow, you’d inject it into a GC-MS/MS system and begin your analysis. This is certainly an over-simplified anecdote, but the point isn’t to discuss the merits of using GC-MS/MS to analyze complex food matrices. This example merely illustrates how much variability there is in the food testing process. Complex instruments, consumables, technicians, samples, etc.—all part of an eventual defensibility exercise.
So knowing that defensibility is both a requirement and a challenge, what’s a forward-thinking lab to do? Engineer defensibility into their processes, of course. But that’s easier said than done. Unless, of course, data is already collected and managed in a disciplined fashion. Even better, so much of the larger data collection process has already been automated thanks to LIMS, so all that’s required when defending a result is a few relatively easy steps.
At a high level, labs must address two main areas: technical quality—including consumable integrity and instrument maintenance and calibration—and staff performance. And much can “go wrong” in these areas if discipline is lacking.
1. Technical quality. Technical quality data includes everything involved with producing an accurate result from an instrument. This presumes flawless staff execution and strict adherence to standard operating procedures (SOPs).
For the strawberry jam analysis above, relevant technical quality data would include reference material certificates, records of approved suppliers, maintenance records, and more. Seems straightforward until one imagines how many times an experiment like this takes place across a busy food lab. The only way to ensure that no misstep compromises a final result is to capture everything within a LIMS as it happens.
Suppliers. From stock solutions to carrier gases, what comes into a lab could affect a result as much as what happens inside the lab. But labs can’t afford to test each shipment of consumables, so they often rely on “approved” suppliers that have earned a reputation for—or can document—quality.
But to defend a result, a technician must use consumables from those pre-approved suppliers. And a LIMS can ensure that they do so on every run. Barcoded materials can be tracked as they arrive, associating them with each supplier and linking the instrument running the test and the materials used to do so. During defense of a test result, a technician need only verify within the LIMS that all consumables originated from approved suppliers. If so, consumables are unlikely to be the fail point.
Consumable quality. The origin of a consumable only tells part of the story. Consumables can, after all, go out of specification during storage or use. The LIMS is indispensable here as well: Lab administrators can configure the system to automatically alert staff when a periodic check is required. This capability significant reduces the likelihood that staff will inadvertently use an out-of-specification consumable that would make the test result indefensible.