Sample Preparation

The results obtained from a new survey on sample preparation techniques were compared with the results of previous surveys from 1991 to March 2013. The survey investigated trends in technologies currently being used, sample loads, sample sizes, automation, the use of solid-phase extraction (SPE) devices (cartridges, disks, plates, tips), SPE chemistries, selection criteria, and problems encountered. Respondents were also asked about sample preparation technologies on the horizon.

This first installment of the “Sample Prep Perspectives” column presents an overview of the primary manual and automated sample preparation techniques-methods that are much the same as those in use today.

A survey of LCGC readers on sample preparation techniques and methodology investigated trends in technologies being used, sample loads, sample sizes, automation, the use of SPE devices (cartridges, disks, plates, tips), SPE chemistries, selection criteria, and problems encountered.

If sample preparation is the most time and labor intense step in the analytical process, and uses the largest amounts of solvents, it stands to reason that sample preparation may present the most significant safety risks in the analytical lab. While most laboratory workers receive significant safety training, we may become numb to the prospect of accidents or get into the mindset that accidents only happen to other people. Given some recent, significant safety incidents, this month we step back and take a quick refresher on safety concerns appropriate during our sample preparation activities.

Researchers at the University of Waterloo in Canada are collaborating with clinicians at Toronto General Hospital to develop preclinical and clinical applications of solid-phase microextraction (SPME). Bethany Degg of The Column spoke to Barbara Bojko from the team to find out more.

Advances in Sample Preparation: Removing Phospholipids from Biological Samples

When developing analytical methods, several parameters are often considered, things like solvent type and amount, sample size, pH, sorptive phases, temperature, time, and more. While some of these considerations can be considered unimportant in a given situation and experience and chemical knowledge can guide us to appropriate starting points, extraction method development is often a one-parameter-at-a-time proposition. A family of statistical approaches, which fall under the category of response surface methodology, are available to screen and optimize several parameters simultaneously.

Advances in Microsampling for In Vivo Pharmacokinetic Studies in Rodents

As expected, the new products introduced in the past year in the area of chromatographic sample preparation, while somewhat limited, mirror the current development in the field.

The benefits of supported liquid extraction (SLE) in sample cleanup and, in particular, the use of a synthetic SLE sorbent are discussed.

When pyrolyzed, macromolecules will decompose into smaller fragments that can have the appropriate volatility for gas chromatography (GC) separation and analysis.

In this installment of "Sample Prep Perspectives," we cover some of the basic scientific principles behind solid-phase extraction (SPE) to allow the correct mode of extraction to be selected through an understanding of how analytes interact with and are separated by the sorbent.

Make your column last forever? Not quite, but you can help prevent its early demise. 

Why should you be concerned about mobile-phase degassing - it's all done automatically, isn't it?

In sample preparation, what does "high-throughput" really mean?

This article discusses the benef ts of using automated dispersive solid-phase extraction (dSPE) rather than standard SPE in urine analysis.

The selective removal of a fat substitute in food products is discussed to demonstrate options for obtaining selectivity during extraction.

In this column, the selective removal of a fat-substitute in food products is discussed to demonstrate options for obtaining selectivity during extraction.

A look at five sample preparation methods where the application of a charge across barriers provides enhanced selectivity

To keep readers informed of the latest developments and trends in sample preparation, LCGC North America occasionally runs reader- and expert-surveys that provide information on overall technology and usage patterns.

The past and future development of analytical supercritical fluid extraction (SFE) is traced in terms of experimental strategies, applications, vendor support, and timely acceptance of the existing technology.

Pressurized high temperature or superheated water is a green extraction solvent used in food, environmental, and traditional medicine studies for the extraction of non-polar and polar analytes including essential oils and spices, agrochemicals, pharmaceuticals, and petrochemicals.

Pressurized fluid extraction (PFE) is an automated extraction technique that uses elevated temperature and pressure to increase the rate and efficiency of the extraction process.

Some sample preparation techniques that were introduced in the past are now being used for new applications.

Microwave accelerated extraction (MAE) was evaluated by the authors of this review in 1999 (1). Since this time, the United States Environmental Protection Agency (USEPA) has promoted the use of SW-846 Method 3546 using MAE for the extraction of organic compounds from solid matrices.

The growing interest in green chemistry requires fresh perspectives on analytical extractions. Reduced solvent consumption, alternative safer solvents, and reasonable energy demands must be balanced with traditional analytical considerations such as extraction yield and selectively.

Modern autosamplers and workstations possess a range of capabilities, in addition to simple liquid handling, that allow automation of sample preparation steps traditionally performed manually.

A review article that summarizes the successful sample preparation strategies that have led to some of the highest peptide and protein identification rates reported in the literature

In contrast to isocratic separations, gradient elution can sometimes seem to be counter-intuitive. Yet with the proper perspective, the things we intuitively understand about isocratic methods apply in a similar manner to gradients.

The authors present the most common and fundamental techniques that address common matrix issues and discuss the critical chemistry considerations.