Analytical Methods Blog

In this Critical Review, José M. Pingarrón, María Pedrero and Susana Campuzano from the University Complutense of Madrid review the use of DNA electrochemical sensors combined with PCR-amplification strategies for the detection of microorganisms.  They show that PCR-amplified DNA hybridization electrochemical sensors exhibit a high sensitivity which is attributable not only to PCR-amplification but also to the detection approaches used.

Interested in knowing more?  Read the full article here; free until 8th April!

Electrochemical genosensors based on PCR strategies for microorganisms detection and quantification
María Pedrero, Susana Campuzano and José M. Pingarrón
Anal. Methods, 2011, Advance Article
DOI: 10.1039/C0AY00755B

Jonathan C. Burley and co-workers from the UK demonstrate, for the first time, the application of Principal Component Analysis (PCA) to the analysis of time-resolved energy-dispersive X-ray diffraction data. Such a new strategy for the analysis of large sets of diffraction data is needed with the increasing use of in situ diffraction for following a variety of chemical processes. PCA is shown to offer significant advantages over traditional curve-fitting methods in terms of speed and lack of potential user bias.

Interested in knowing more? Read for free until April 4th.

The application of statistical methodology to the analysis of time-resolved X-ray diffraction data
Jonathan C. Burley, Dermot O’Hare and Gareth R. Williams
Anal. Methods, 2011, Advance Article
DOI: 10.1039/C0AY00772B

The authors explain how the challenge test works, its historical context and interpret the results using pharmacopoeia criterion.

The challenge test predicts the antimicrobial abilities of cosmetic preservatives over a prolonger period of time. Salgado and colleagues critique the efficacy of the challenge test for analysisng preservative effectiveness in this critical review.

Read it for free until the 1^st April.

The use of the challenge test to analyse preservative efficiency in non-sterile cosmetic and health products: applications and critical points
F. A. M. Fiorentino, M. Chorilli and H. R. N. Salgado
Anal. Methods, 2011
DOI: 10.1039/C0AY00597E

Slobodan Šašić  and colleagues from Pfizer describe the use of microspectroscopic chemical imaging with white light optical microscopic imagery for monitoring the agglomeration of pharmaceutical ingredients during the manufacturing process, in this HOT paper.

In a separate paper, Šašić compares the performance of three chemical mapping and imaging platforms to determine the distribution of the active pharmaceutical ingredient in various pharmaceutical products.

Both Analytical Methods papers are free to access until the 1st March using the links below:

Monitoring of API particle size during solid dosage form manufacturing process by chemical imaging and particle sizing
Slobodan Šašić, Weili Yu and Lin Zhang
Anal. Methods, 2011
DOI: 10.1039/c0ay00562b

Parallel imaging of active pharmaceutical ingredients in some tablets and blends on Raman and near-infrared mapping and imaging platforms
Slobodan Šašić
Anal. Methods, 2011
DOI: 10.1039/c0ay00532k

A team from Japan report that biological polyamines can be detected by a colorimetric sensing method based on a stimuli-responsive inclusion complex of anionically-modified amylose. Polyamines play a key role in cellular processes and increased levels in the urine can indicate a cancer diagnosis.  Current polyamine detection methods are time-consuming and costly so development of a convenient sensing method is important.

The “iodo-starch reaction”, involving the encapsulation of iodine by amylose resulting in a blue or purple colour, has long been used for the detection of starch and iodine. Yasumasa Kanekiyo and co-workers from the Kitami Institute of Technology in Japan describe the development of a simple, functional and eco-friendly sensing method for polyamines in this HOT Article.

The group synthesised amylose modified with carboxyl groups and demonstrated that an aqueous solution of the modified amylose and iodine was clear due to the disruption of the inclusion complex by electrostatic repulsion between the anionic carboxylate groups and polyiodide.  Upon addition of spermine (a polyamine) the solution clearly changed to bluish purple. The colour change was attributed to the encapsulation of iodine into the helical cavity of amylose, triggered by the electrostatic association between the amylose and spermine.

Interested in knowing more? Read for free here until 10^th March!

Colorimetric sensing method for polyamines utilising an inclusion complex of stimuli-responsive amylose
Masayuki Tsuchiya, Yuta Nomiyama, Wakana Takayoshi, Yuto Iwami and Yasumasa Kanekiyo
Anal. Methods, 2011, Advance Article, Paper
DOI: 10.1039/C0AY00690D

Specimens were placed on a board and a probe moved over the wings

A way to identify individual butterflies from the same species has been designed by scientists in Hungary, who say that the technique could be used to analyse delicate museum samples without destroying them.

László Biró at the Research Institute for Technical Physics and Materials Science and colleagues have developed an instrument that allows reflectance spectroscopy to be carried out on specimens without physically damaging them.

Want to know more?  Read Harriet Brewerton’s news article at Chemistry World or access the full paper for FREE:

Color based discrimination of chitin–air nanocomposites in butterfly scales and their role in conspecific recognition
Gábor Piszter, Krisztián Kertész, Zofia Vértesy, Zsolt Bálint and László Péter Biró
Anal. Methods, 2011
DOI: 10.1039/c0ay00410c