Analytical Methods Blog

Oliver Strohmeier and his colleagues from the University of Freiburg in Germany have developed a novel PCR-based platform to detect food-borne pathogens. Named “LabDisk”, the device implements centrifugal microfluidics for sample separation, and can be subsequently transferred to a commercially available thermocycler for real-time PCR amplification of pathogens including Listeria monocytogenes, Salmonella typhimurium, EHEC, Staphylococcus aureus, Citrobacter freundii, and Campylobacter jejuni. Importantly, LabDisk incorporates on-chip quality controls to help validate test results, and enables quantitative as well as qualitative testing. This new approach brings molecular detection one step closer to fully integrated sample-to-answer food testing.

"LabDisk" for Detection of Foodborne Pathogens

Download the full article, free until March 7th!

Real-time PCR based detection of a panel of food-borne pathogens on a centrifugal microfluidic “LabDisk” with on-disk quality controls and standards for quantification

Oliver Strohmeier, Nico Marquart, Daniel Mark, Günter Roth, Roland Zengerle and Felix von Stetten

DOI: 10.1039/C3AY41822G, Paper

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LC-MS for Animal Identification

Studying rare or endangered species of wild animals is no easy task. Analysis of animal tracks and fecal matter left behind can provide some clues for species identification, as well as insight into animal behavior and habitation. However, these identification signs are elusive, and often confounded by variations in environmental conditions, as well as animal health and diet. While methods of molecular analysis such as DNA sequence analysis of animal scat samples can provide more informative answers, DNA contamination from other mammals can make accurate identification difficult. To circumvent some of these limitations, Udaya Nasini, Ali Shaikh and colleagues from the University of Arkansas in Little Rock, USA, have demonstrated the use of liquid chromatography-mass spectrometry (LC-MS) to determine the composition of bile acids in scat samples. Analysis using LC-MS provides a metabolic pattern that is characteristic of a distinct species, and in turn enables effective identification.

Read more about this work by accessing the link below. This paper will be free to read for the next three weeks.

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Determination of bile acid profiles in scat samples of wild animals by liquid chromatography-electrospray mass spectrometry
Udaya B. Nasini, Nandan Peddi, Punnamchandar Ramidi, Yashraj Gartia, Anindya Ghosh and Ali U. Shaikh
Anal. Methods, 2013,5, 6319-6324
DOI: 10.1039/C3AY41048J

Drug discovery, development, and manufacturing widely make use of high performance liquid chromatography (HPLC) to separate compound mixtures for identification, quantification, and purification of individual components. Hence, the quest for the “next generation” of HPLC instruments is in high demand for improved analysis. Monica Yang and colleagues from Merck and Eksigent corporations have tested the performance of Eksigent Express LC Ultra micro high pressure liquid chromatography for real-world pharmaceutical application. By combining the capability of microflow HPLC, and the function to separate under high pressures, the new instrument enables fast separation efficiency, cost reduction and high system reproducibility.

Mixture Separation Using Eksigent ExpressLC Ultra HPLC

Find out more about this recent advancement by accessing the link below:

Evaluation of micro ultra high pressure liquid chromatography for pharmaceutical analysis
Monica (Mei) Yang ,  Xiaoyi Gong ,  Wes Schafer ,  Don Arnold and Christopher J. Welch
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26435A

Trace amounts of some metals can have highly toxic effects on diverse life forms. Furthermore, over accumulation of other metals can give rise to various diseases. Quantitative imaging techniques such as laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) can help identify changes in metal content in biological materials. The versatility of LA-ICP-MS however, is somewhat limited as calibration accuracy and precision are largely dependent on the sample matrix used. Hence, acquiring reliable data can be a challenge due to the lack of well characterized reference standards.

Calibration Procedure Using LA-ICP-MS

To address this issue, Philip Doble and colleagues from the University of Melbourne, Australia, have developed a “general guide” to creating matrix-matched standards to monitor trace metals in brain tissue.

Learn more about this research by accessing the link below. This paper will be free to read until April 2^nd.

Protocol for production of matrix-matched brain tissue standards for imaging by laser ablation-inductively coupled plasma-mass spectrometry
Dominic J. Hare ,  Jessica Lear ,  David Bishop ,  Alison Beavis and Philip A. Doble
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26248K