In a new webinar, Pace Analytical explains how they use two complementary techniques (ion chromatography and discrete analysis) to ensure effective and sustainable wet chemistry testing. Dr. Carl Fisher, Thermo Fisher Scientific, contributed to this post.
Two techniques are better than one
Today’s environmental labs are under enormous pressure to reduce costs and improve turnaround times while doing their work to measure contaminants in liquid, solid and gaseous samples.
One such company is Pace Analytical, the world’s largest American-owned laboratory network, with locations across the United States specializing in environmental and pharmaceutical testing. Pace laboratories rapidly and accurately test thousands of samples weekly.
Like most other service laboratories, Pace is striving to decrease costs and increase efficiencies, without compromising quality of results. An increasingly large part of testing costs is related to personnel costs. Minimizing use of analytical consumables (e.g., solvents, reagents) is another concern, not only to manage costs but to meet sustainability goals.
“Our main challenge is the sheer number of samples we process because many of our labs run thousands of samples per week,” said Timothy Traynor, Technical Specialist, Pace’s IDEA Lab.
Two complementary techniques: ion chromatography and discrete analysis
For several reasons — including a commitment to better sustainability — Pace has chosen two solutions from Thermo Fisher Scientific: the Thermo Scientific Dionex Integrion ion chromatography (IC) system and the Thermo Gallery Aqua Master discrete analyzer. Here’s the rationale:
Making the case for ion chromatography
Ion chromatography (IC) is a well-established analytical method that expands the breadth of water analyses by offering distinct capabilities that include trace level determinations for a broad spectrum of analytes.
At Pace, IC is used for a variety of tests. It’s used for the seven common anions (fluoride, chloride, nitrite, bromide, nitrate, orthophosphate and sulfate). It’s also used for oxyhalides, perchlorate and hexavalent chromium analysis, as well as for determination of organic acids. IC is also used to test for several common cations — the alkali/alkaline earth metals and ammonium.
“Why do we use IC? First and foremost is that, by virtue of it being chromatography, the specificity is unmatched by any of the other wet chemistry methods for the same analytes,” explained Traynor. “Interferences can typically be seen and accommodated for, reducing the number of false positives or negatives.”
Traynor says Pace also chose Dionex Integrion IC system for these reasons:
- Less sample volume: Sample volume requirements are low — often less than one half of one milliliter.
- Less waste: The only reagent needed is eluent, which for Pace’s most common tests, are either carbonate/bicarbonate or hydroxide solutions. Therefore, waste is easily treated and disposed of in-house.
- Sensitivity: Depending on the column and system, the sensitivity can be better than any other wet chemistry method used. That’s due to the sensitivity of suppressed conductivity detection and chromatographic peak integration versus a simple amplitude measurement by a probe or a spectrophotometer.
- Efficiency: Seven or more analytes can be acquired by a single run on a single sample aliquot.
- Method requirements: Some methods require the lab to use IC for specific analytes, such as perchlorate and the other oxyhalides.
- Productivity: Automated sample introduction means the analyst must only load the autosampler with standards and samples, and can focus on other tasks.
Making the case for discrete analysis
Discrete analyzers are robust, easy to use, and provide parallel measurement of multiple analytes in as fast as 10 minutes. Compared to traditional wet chemistry techniques, they provide equivalent or better data quality while speeding up the determination process significantly. Adding this automation to Pace’s laboratory workflow significantly reduces the amount of reagent used and analysts’ bench time.
“Our goal is to finish more work, faster, with more efficiency and sustainability, without compromising quality,” said Traynor. “The Gallery Aqua Master Discrete Analyzer provides equivalent or better data quality, while speeding up the determination process significantly. Adding this automation across Pace would significantly reduce the amount of reagent used and analysts’ bench time, resulting in reduced costs and increased productivity.”
Pace also appreciates these benefits:
- Automation: Discrete analysis is fully automated, so for most tests, the analyst has only to load samples, standards, and reagents, tell the software what tests go with what samples and walk away.
- Less sample volume and waste: Discrete requires very little sample volume. While it does use hazardous reagents, they are in very small volumes when compared to traditional colorimetric methods. Total combined sample and reagent waste is less than one half of one milliliter per assay.
Benefits already being realized with discrete analysis
Since first evaluating the Gallery Aqua Master, Pace has realized several benefits, notably the impact of increased automation on productivity and the quality of results, with less reagent consumption and chemical waste. Traynor highlighted a few specific features that make the Gallery Aqua Master discrete analyzer an ideal choice for certain environmental analyses at Pace:
- Automation increases productivity: “The main reason to switch to discrete analysis is to free up the analyst to focus on other tasks such as sample prep or data reduction,” said Traynor. “The Gallery discrete analyzer will quickly determine an analytical batch without the need for much analyst intervention. Ideally, automation like this allows the analyst to not only get more samples finished quickly and accurately, but to then focus more effort on whether the results make sense.”
- Automation improves results quality by minimizing human error: Traynor explained, “Real life gets in the way of even the most experienced and diligent scientist. Since all reagent additions are done robotically, there are fewer variations in volume dispensing.”
- Low reagent consumption and chemical waste: A big push in Pace right now is sustainability and this is one area where discrete analysis excels,” said Traynor. “Here the benefit of discrete analysis is reduced reagent use, because with a flow injection analyzer you often use 1 to 2 milliliters of reagent per sample whereas with the discrete analyzer it’s often 2 to 300 microliters total. From a sustainability standpoint, a discrete analyzer is preferable where it can be used efficiently.”
The bottom line: IC and discrete analysis make a powerful combination
Ion chromatography and discrete analysis provide the modern analytical lab with powerful tools for getting the job done quickly, accurately and sustainably. According to Traynor, having access to both instruments supports productive workflows, where tests needed ASAP can be run on discrete, and samples that need more selectivity or more reportable analytes may be run on IC. Both instruments have sustainable advantages over traditional methods due to reagent use, and having both instruments equips labs to run most of their tests on just two instruments.
Given the complementary nature, which is best — IC or DIA? It depends!
Pace’s labs have access to both technologies, so which one should be used when? According to Traynor, the decision is usually made by first asking which methods must be cited. Drinking waters have specific methods that must be followed precisely and may not give users an option. Secondly, Pace labs determine how quickly the results are needed. Method hold times and client due dates often determine which technology users have time to use. For some methods, such as nitrite and orthophosphate, the hold times are 48 hours. For these tests, discrete analysis would be a better method. Finally, review methods and application notes to see if the target reporting limits are supported by the desired technology.
Pulling it all together: Two techniques provide complementary coverage
In summary, the combination of the two independent technologies provides complementary coverage for the most common parameters in wet chemistry labs. It also provides great flexibility for laboratories to match sample and test requirements based on considerations such as sensitivity, regulatory requirements, speed and throughput, and client due dates.