Unlike many of my friends and colleagues in the commercial lab business, I’m looking for those weird projects that just don’t fit in a commercial lab setting. In fact, that’s what I usually did even when working in the commercial lab business. I was often the guy asked to “figure out” how to do the “weird project.” The "weird project" sometimes requires a new analysis technique, but more often requires a new sampling or sample preparation technique that can be used with existing analytical techniques. Another challenge is often validating the entire procedure to ensure that statistically valid data are being produced. Many times the work can be done by the commercial lab once the modified sampling and sample preparation has been done. That can result in synergy between large labs with plenty of analytical capabilities and Stites & Associates. Let me give just a few examples from past experience to illustrate the point.
Tars in Syngas from Biomass:
Gasification of biomass is plagued by the formation of “tars.” These are a wide variety of sticky, semi-solid substances that are generated primarily from the lignin in woody biomass. It turns out that many of these substances can be seen on a standard BNA run done in an environmental laboratory. Hence, a standard BNA run can be used as an indicator of tar formation and gasifier performance. The biggest challenge is pulling a representative sample from the gas stream. The “tars” have a wide variety of boiling points and solubilities. They often form semi-solid droplets in the gas stream. The key is designing an appropriate sampling system. This may include heated lines, solvent traps and even filters depending on sample point and the purpose of the test. No one sampling system is likely to give a complete and unambiguous “tar number.” Nevertheless, with proper design the data can be very useful for troubleshooting purposes. Stites & Associates has worked with several labs on several projects of this type with good success.
Water in Processes:
One of the most frustating analysis is water content of "real samples." It is ubiquitous and often a very important compound that shows up in the most inconvenient places. There are many ways to measure water content of a sample. They include volumetric separation, co-distillation, Karl Fischer Titration, thermal drying, chemical adsorption, FTIR, dew point measurement and GC, just to name some of the more common. Unfortunately, all of these can have serious limitations and interferences. Depending on the matrix and sampling conditions, measuring water content often has very serious bias and/or precision problems.
Nearly every commercial laboratory has one or more of these techniques available. Few labs have a complete suite of techniques. In most cases the techniques they have are designed for the types of samples that they commonly receive. The key is collecting the sample in a way that does not adulterate the water content, but can be analyzed by one of the laboratory techniques available. Sometimes simple drying and weighing will be “close enough.” Even then, proper sampling (including taking an aliquot in the lab) is crucial to reliable data. Other times absorption in a solvent followed by analysis can work well. Stites & Associates has worked with several labs in collecting and analyzing solid, liquid and even reactive gas samples at high temperature for water content.
Carbohydrates in Enzymatic Processes:
Carbohydrates can be difficult to measure well, but there are now many reasonably reliable HPLC methods. Unfortunately, most real world applications are taken from dynamic processes where carbohydrate concentrations are not stable. One example would be the enzymatic hydrolysis of starch, cellulose and other macro-molecules. To track the progress of an enzymatic process it is important to analyze the carbohydrates “real time.” Often that means stopping the process in the sample until the analysis can be completed. This must be done without adulterating the carbohydrates under consideration. Stites & Associates has worked with labs to design sampling and preservation techniques that can be used to ship samples to remote labs – including overseas.
These are just a few examples where Stites & Associates has worked with labs to make “weird projects” reasonable to perform in commercial labs. We have focused on some of the sampling and sample preparation aspects, but there is a whole host of Experimental Design issues that we haven’t discussed here. When it comes to validating the methodology used in a “weird project” or attempting to draw statistically valid conclusions from the results, Stites & Associates again can help.
If you have a “weird project,” we’d like to hear about it. Maybe we can help. We’d be happy to take a look at it and give you an honest assessment. Frequently what is being asked turns out not to be feasible. Nevertheless, it is usually possible to come up with an approach that goes a long way toward solving the real problem – often more cost effectively than the original approach. Give us a call at (912) 247-6120 or write us at [email protected].
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