Emerging flow injection mass spectrometry methods for high-throughput quantitative analysis.

Where does flow injection analysis mass spectrometry (FIA-MS) stand relative to ambient mass spectrometry (MS) and chromatography-MS? Improvements in FIA-MS methods have resulted in fast-expanding uses of this technique. Key advantages of FIA-MS over chromatography-MS are fast analysis (typical run time <60 s) and method simplicity, and FIA-MS offers high-throughput without compromising sensitivity, precision and accuracy as much as ambient MS techniques. Consequently, FIA-MS is increasingly becoming recognized as a suitable technique for applications where quantitative screening of chemicals needs to be performed rapidly and reliably. The FIA-MS methods discussed herein have demonstrated quantitation of diverse analytes, including pharmaceuticals, pesticides, environmental contaminants, and endogenous compounds, at levels ranging from parts-per-billion (ppb) to parts-per-million (ppm) in very complex matrices (such as blood, urine, and a variety of foods of plant and animal origin), allowing successful applications of the technique in clinical diagnostics, metabolomics, environmental sciences, toxicology, and detection of adulterated/counterfeited goods. The recent boom in applications of FIA-MS for high-throughput quantitative analysis has been driven in part by (1) the continuous improvements in sensitivity and selectivity of MS instrumentation, (2) the introduction of novel sample preparation procedures compatible with standalone mass spectrometric analysis such as salting out assisted liquid-liquid extraction (SALLE) with volatile solutes and NH4(+) QuEChERS, and (3) the need to improve efficiency of laboratories to satisfy increasing analytical demand while lowering operational cost. The advantages and drawbacks of quantitative analysis by FIA-MS are discussed in comparison to chromatography-MS and ambient MS (e.g., DESI, LAESI, DART). Generally, FIA-MS sits 'in the middle' between ambient MS and chromatography-MS, offering a balance between analytical capability and sample analysis throughput suitable for broad applications in life sciences, agricultural chemistry, consumer safety, and beyond.

Report on the 12th International Conference on Flow Analysis.

The 12th International Conference on Flow Analysis, referred to as 'Flow Analysis XII' was a 5-day scientific meeting that covered all recent advances in the field of flow analytical techniques. The most interesting presentations pertaining to bioanalytical work are summarized in this report.

Microfluidics and the life sciences.

The field of microfluidics, often also referred to as "Lab-on-a-Chip" has made significant progress in the last 15 years and is an essential tool in the development of new products and protocols in the life sciences. This article provides a broad overview on the developments on the academic as well as the commercial side. Fabrication technologies for polymer-based devices are presented and a strategy for the development of complex integrated devices is discussed, together with an example on the use of these devices in pathogen detection.

Integration column: Microfluidic high-throughput screening.

Biology has always been a heavily technology limited field. Burgeoning fields such as systems biology require the development and implementation of new technologies, enabling high-throughput and high-fidelity measurements of large systems. Microfluidics promises to fulfil many of the requirements put forth. Here I will discuss the various approaches employed to date for performing high-throughput screening experiments on-chip, encompassing biochemical, biophysical, and cell-based assays.

Mass spectrometry analysis of new chemical entities for pharmaceutical discovery.

In this Section, we review the applications of mass spectrometry for the analysis and purification of new chemical entities (NCEs) for pharmaceutical discovery. Since the speed of synthesis of NCEs has dramatically increased over the last few years, new high throughput analytical techniques have been developed to keep pace with the synthetic developments. In this Section, we review both novel, as well as modifications of commonly used mass spectrometry techniques that have helped increase the speed of the analytical process. Part of the review is devoted to the purification of NCEs, which has undergone significant development in recent years, and the close integral association between characterization and purification to drive high throughput operations. At the end of the Section, we review potential future directions based on promising and exciting new developments.

Review of recent applications of flow injection spectrophotometry to pharmaceutical analysis.

Pharmaceutical analysis is one of the most important fields in analytical chemistry. The discovery of new drugs and the on-going update of international regulations for the safety and efficacy of pharmaceutical formulations demand the continuous development of new analytical methods. Inevitably, automation plays an important role, especially when a lot of samples have to be analyzed in the minimum of time. The present study reviews the applications of flow injection (FI) spectrophotometry to the determination of active pharmaceutical ingredients (APIs) in their respective formulations. However, the topic covered in this study is important not only to pharmaceutical analytical scientists. The principles, figures of merit and "chemistry" of the presented methods can be of interest to bio-analytical and clinical chemists as well for the analysis of biological samples, to environmental analysts that study the up-to-date demand of the determination of the fate of pharmaceuticals in the environment and even to toxicologists and forensic scientists. This review covers scientific contributions published later than 2000. A variety of FI procedures based on homogeneous (direct UV measurements, colour-forming reactions, metal-drug interactions) and heterogeneous (optical sensors and solid-phase reactors) systems are discussed. A third section covers on-line sample pretreatment (solid-phase extraction, liquid-liquid extraction, on-line digestion, etc.).

Microfluidic immunosensor systems.

Immunosensing microfluidic devices are reviewed. Devices are commonly fabricated in glass, silicon, and polymers, with polymers seeing greater attention in recent years. Methods have been developed to immobilize antibodies and other molecules and resist non-specific adsorption through surface modification. The most common detection method is fluorescence, followed by electrochemistry. Various microfluidic designs have been reported for immunoassay applications. The observed trends in microfluidic immunoassay applications closely resemble the trends of general immunoassays, where large molecules are detected principally through a sandwich procedure, while competitive assays are used to detect smaller molecules. The following future trends are suggested: more sensitive detection, increased integration and miniaturization, multianalyte analysis, more robust reagents and devices, and increased functionality of surface treatments.

Microfabricated electrophoresis systems for DNA sequencing and genotyping applications: current technology and future directions.

Many routine genomic-analysis assays rely on gel electrophoresis to perform size-selective fractionation of DNA fragments in the size range below 1 kb in length. Over the past decade, impressive progress has been made towards the development of microfabricated electrophoresis systems to conduct these assays in a microfluidic lab-on-a-chip format. Since these devices are inexpensive, require only nanolitre sample volumes, and do not rely on the availability of a pre-existing laboratory infrastructure, they are readily deployable in remote field locations for use in a variety of medical and biosensing applications. The design and construction of microfabricated electrophoresis devices poses a variety of challenges, including the need to achieve high-resolution separations over distances of a few centimetres or less, and the need to easily interface with additional microfluidic components to produce self-contained integrated DNA-analysis systems. In this paper, we review recent efforts to develop devices to satisfy these requirements and live up to the promise of fulfilling the growing need for inexpensive portable genomic-analysis equipment.

Why the move to microfluidics for protein analysis?

There has been a recent trend towards the miniaturization of analytical tools, but what are the advantages of microfluidic devices and when is their use appropriate? Recent advances in the field of micro-analytical systems can be classified according to instrument performance (which refers here to the desired property of the analytical tool of interest) and two important features specifically related to miniaturisation, namely reduction of the sample volume and the time-to-result. Here we discuss the contribution of these different parameters and aim to highlight the factors of choice in the development and use of microfluidic devices dedicated to protein analysis.

Discovering flow injection: journey from sample to a live cell and from solution to suspension.

Twenty years after its inception, flow injection is seen as an ever-expanding method, as new modifications are discovered such as flow injection cytoanalysis and the flow injection on renewable surfaces technique. In this review, a personal view of the future rather than the history of flow injection is given, with comment on how research is actually being conducted.