Douglas E. Raynie

The past couple instalments of “Sample Preparation Perspectives” have looked at current trends in the field. Another recent trend is dried blood spot analysis and other analysis methods using minute sample amounts. This month we take a quick look at the role of sample homogeneity and the determination of sample size. Microsampling approaches, including dried blood spots, are discussed.

The rise of microsampling raises questions about representative sampling.

This yearly report on new products introduced at Pittcon or in the preceding year covers instruments, accessories, and sorbents for sample preparation.

This yearly report on new products introduced at Pittcon or in the preceding year covers sample preparation instruments.

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 instalment of “Sample Preparation Perspectives” compares the results obtained from a new survey on sample preparation techniques with the results of previous surveys from 1991 to March 2013. The survey investigated trends in areas such as 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.

Cloud-point extraction (CPE) manipulates temperature and surfactant concentration to move aqueous solutes into a micelle phase for separation. Although CPE has been around for some time, it is still considered an emerging technique. Much of the development, and most applications, of CPE have dealt with extraction and preconcentration of inorganic solutes. More recently, attention has turned to the use of CPE in the isolation of organic solutes. This month, we review how CPE works and focus on applications for extracting organics.

Cloud-point extraction (CPE) manipulates temperature and surfactant concentration to move aqueous solutes into a micelle phase for separation. Although CPE has been around for some time, it is still considered an emerging technique. Much of the development, and most applications, of CPE have dealt with extraction and preconcentration of inorganic solutes. More recently, attention has turned to the use of CPE in the isolation of organic solutes. This month, we review how CPE works and focus on applications for extracting organics.

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.

Given some recent, significant safety incidents, this month we step back and take a quick refresher on safety concerns to be aware of during our sample preparation activities.

Recently, Nature and Science Citation Index listed the 100 most cited research papers of all time. Two of these are the classic Bligh-Dyer and Folch lipid extraction methods from the late 1950s. This month we will take a look at the lasting impact of these papers and explore the current state of lipid extractions, including lipidomics.

Recently, Nature and Science Citation Index listed the 100 most cited research papers of all time. Two of these are the classic Bligh-Dyer and Folch lipid extraction methods from the late 1950s. This month we take a look at the lasting impact of these publications and explore the current state of lipid extractions, including lipidomics.

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.

In this instalment, an overview of response surface methodology is presented and its application to developing extraction methods is discussed.

This yearly report on new products introduced at Pittcon (or in the preceding year) covers sample preparation instruments.

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.

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

The fundamentals and applications of pyrolysis-G

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.

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

Sample preparation has often been viewed as the bottleneck in analytical procedures. Surveys have shown that time is typically the most frequent problem area for sample preparation procedures. While newly developed extraction techniques address time, modern chromatography advances are also moving towards faster separations. Based on these considerations, what is high-throughput sample preparation? Do modern extraction methods adequately address the issue of time? How can we address the analytical need for speed?

This article introduces some of the concepts behind green chemistry, covering solvent selection and extraction techniques.

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.

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.

Miniaturization and solvent substitution are two key approaches.