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With an ACN shortage gripping the industry, sample prep has become more critical than ever to the productivity of the modern separations lab. Here our experts explore this topic.
What new developments in sample prep have you the most intrigued?
Johnson: Within the area of aqueous analysis and sample prep, there are two areas that I am most intrigued with. One is the ability of developing SPE disks with unique sorbent materials that can selectively extract only those compounds of interest, such as MIP's. The other is to advance the principles of solvent evaporation such that organic solvents can be evaporated quickly, while maximizing the recovery of the more volatile compounds.
Coyer: There have been some interesting developments in solid phase extraction. There are new procedures in micro-extraction, dispersive solid-phase extraction (Quechers), 48/96 well plate formats, and in-line sample clean up.
Roenneburg: Fraction trapping.
What sample prep application area do you see growing the fastest?
Johnson: Due to the growing concern over pharmaceutical and personal care products in drinking water supplies, I see this as a key area to focus on. The need to handle a large number of samples, to achieve lower detection limits, and to perform this extraction cost effectively and efficiently, will be important.
Coyer: There has been some thought that dilute and shoot in LC–MS analysis would be the fastest growing type of sample preparation. Unfortunately, there have been matrix effects that have slowed down its use in certain matrix applications. Several vendors have introduced liquid-handling devices that could be used in plate extraction formats. This seems to have gotten interest so as to free up extraction technicians with either walk-away or semi-automated extraction.
Roenneburg: Solid phase extraction. More and more people are looking for automation of this process.
What obstacles stand in the way of further advances in sample preparation?
Johnson: One of the biggest obstacles I see in the advancement of sample preparation for the analysis of organic compounds in aqueous samples is the time it takes for EPA methods to be developed and promulgated. Companies may feel disinclined to spend R&D dollars and develop new instruments for sample prep with the extended time frame and the fact that there is no guarantee that new analytical methods would even be approved.
Coyer: Cost. Everyone is conscious of cost in the current economy. There are certain costs that are fixed and the highest cost seems to be in the labor to process and prepare samples. There has been a trend to invest in higher cost (more sensitive) instrumentation. Some of that thought has been done with the idea that it will limit sample preparation. The more sensitive the instrument, the more sensitive it is to both the analytes and the unwanted matrix. It is always a trade-off between sample preparation and sensitivity.
Roenneburg: Software interfaces and ease of use. In order for more people to adopt automation in sample prep, the software needs to continue to become easier and easier to use and understand. The biggest challenge is that most users still don't want to sacrifice features. The more features and functions you have in a software package, then the more complex it tends to become. So the biggest challenge is to find the right balance of capabilities vs. complexity.
What do you see in the future for the field of sample prep technology?
Johnson: From my perspective of analyzing for organics in aqueous samples, this is always the tough question to try and answer. Everyone would like to be able to process smaller sample volumes, i.e. a few mLs at most, and still be able to detect extremely low detection limits. But the reality is that there will still be a need to handle sample sizes up to 50 liters or more (to concentrate the sample), in order to detect these extremely low levels of contaminants.
Coyer: a) More automated plate extraction; b) a new generation of certain phases for solid phase extraction; c) a balance between organic solvent usage, sample size and sensitivity requirements; and d) smaller sample volumes and an emphasis on less sampled matrices (i.e., oral fluid, hair, sweat, etc.).
Roenneburg: The future of sample prep is further automation and more sophisticated and simpler software to control it all. If the software can become so easy to use that anyone could walk up and run it, then it will only further the growth in the market place.
Robert S. Johnson
Horizon Technology, Inc.