Analytical Methods Blog

Picture of 5 interconnecting microfluidic components

A new and fast microchip-inspired analytical device based on standard Plexiglas tubes has been developed by researchers in Brazil.
The team, led by Carlos Garcia from the University of Sao Paulo, propose a device based on 5 plastic microfluidic components that serve as both the injector and the reservoir. The plastic components are connected with standard capillary tubes that easily enable the in-channel detection of analytes by a variety of techniques including electrophoresis. To demonstrate the applicability of this design, the researchers performed efficient analysis of inorganic cations by capillary electrophoresis on soil samples.
The microchip-capillary electrophoresis devices commercially available at the moment are still expensive and do not always offer the best analytical performances. This new microfluidic device developed using cheap and simple fabrication materials is an attractive approach for portable and rapid analytical instrumentation.

To read the full article, free to read until March 6th, please access the link below:

Microfab-less microfluidic capillary electrophoresis devices
Thiago P. Segato ,  Samir A. Bhakta ,  Matthew T. Gordon ,  Emanuel Carrilho ,  Peter A. Willis ,  Hong Jiao and Carlos D. Garcia
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26392D

Antibiotics provide vital treatment in fighting bacterial infection, but over time some have become phased out or even toxic to humans.

Miniaturized device for detection of chloramphenicol in water

One of these is chloramphenicol. Although banned in the European Union, chloramphenicol continues to be used as a cheap remedy in veterinary medicine and can lead to contaminated water and food for our consumption. One technique to test for this contaminant, solid phase extraction (SPE), purifies samples effectively, but requires a pump and a laboratory setting.

Alternatively, Sheng Liu, from the Chinese Academy of Sciences, and colleagues developed a simple yet portable miniaturized SPE (MSPE) device capable of detecting chloramphenicol in water, which has been difficult to test using other methods. A macroporous resin captures and concentrates the chloramphenicol before it passes through an HPLC, all within a 1.5 kg mass instrument. This new technique directly detects low concentrations of chloramphenicol in water, and demonstrates the capacity to function at contaminated locations.

To know more about the study, please click on the link below. This paper will be free to read for the next two weeks.

On-site solid phase extraction and HPLC determination of chloramphenicol in surface water and sewage
Sheng Liu ,  Xian-Zheng Wu ,  Zi-Hui Gao and Fang Jiao
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26162F

Take a look at this great list of selected HOT articles recently published in Analytical Methods! Topics include nanoparticle-based colorimetric anticancer drug detection methods and ultra performance liquid chromatography-tandem mass spectrometry for multiple bile acids detection.

Check out also the new review by Edward Randviir and Craig Banks on electrochemical impedance spectroscopy. All these papers will be free for you to read until February 18th. 

Electrochemical Impedance Spectroscopy: An Overview of Bioanalytical Applications
Edward P Randviir and Craig E Banks
Anal. Methods, 2013, Accepted Manuscript
DOI: 10.1039/C3AY26476A

Application of an electronic tongue towards the analysis of brandies
Xavier Cetó ,  Matias Llobet ,  Joan Marco and Manel del Valle
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26066B

Potential of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry to monitor the Ag body burden in individual Daphnia magna specimens exposed to Ag nanoparticles
Martín Resano ,  Ana C. Lapeña and Miguel A. Belarra
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26456K

Self-powered herbicide biosensor utilizing thylakoid membranes
Michelle Rasmussen and Shelley D. Minteer
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26488B

Quantification of Multiple Bile Acids in Uninephrectomized Rats Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry
Carlos A Penno ,  Denis Arsenijevic ,  Thierry Da Cunha ,  Gerd A Kullak-Ublick ,  Jean-Pierre Montani and A Odermatt
Anal. Methods, 2013, Accepted Manuscript
DOI: 10.1039/C3AY26520J

Colorimetric anticancer drug detection by gold nanoparticle-based DNA interstrand cross-linking
Xiaoji Xie ,  Renren Deng ,  Feng Liu ,  Wei Xu ,  Sam Fong Yau Li and Xiaogang Liu
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C3AY26422J

Trace concentrations of cadmium in water, soil and industrial settings can have devastating health effects if not detected. Furthermore, measuring accurate cadmium levels in these complex samples is hindered by signal interference from other metals such as tin, molybdenum, and zirconium.

Robert Thompson and Steven Christopher in the United States developed a four-step separation methodology to remove these metals, and then used inductively coupled plasma mass spectrometry to measure cadmium concentrations. For this procedure, commercially available solid phase extraction cartridges isolate most of cadmium and strong ion exchange chromatography removes tin and molybdenum. This unique sample preparation facilitates the detection of low cadmium concentrations in marine sediment and rice flour which contain high levels of tin and molybdenum respectively.

Determination of cadmium in samples containing molybdenum and tin

To know more about this study, please access the link below. This paper will be free to read until February 18th.

Novel separation for the determination of cadmium by isotope dilution ICP-MS in samples containing high concentrations of molybdenum and tin
Robert Q. Thompson and Steven J. Christopher
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26212F

Detection of selenium using graphite-based sensors

Researchers from the Manchester Metropolitan University reported the first example of graphite-based sensors to detect selenium in drinking water.
Selenium is a trace mineral nutrient essential as for all animals, but it is extremely toxic if the intake dose exceeds 400 µg per day. Both the European Union and United States Environmental Protection Agency (EPA) have set the limits for selenium in drinking water to of 10 µg/L and 50 µg/L respectively.

Today, the gold-based electrodes which are traditionally used to detect selenium are very expensive. With this work, Craig Banks and his group address the problem proposing a graphite based sensor to detect selenium in water. They fabricated special screen-printed graphite electrodes and detected low concentrations of selenium in their laboratory tap water, with a limit of detection which fell below those set by the EPA. According to the authors, this new graphite-based sensor could represent an appealing alternative to the gold based electrodes currently used.

To know more about this work, click on the link below. This paper will be free to read until January 24th.

Electroanalytical sensing of selenium(IV) utilising screen printed graphite macro electrodes
Athanasios V. Kolliopoulos ,  Jonathan P. Metters and Craig E. Banks
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26041G

Take a look at the new detection methods described in these HOT articles in Analytical Methods! They include detection of medicinal products such as ginseng using near infrared spectral fingerprints and determination of lead in animal bone powder by X-ray fluorescence spectroscopy. These papers will be free to read until January 24th.

Expeditious identification and semi-quantification of Panax ginseng using near infrared spectral fingerprints and multivariate analysis
Juan Ricardo Lucio-Gutiérrez ,  Jordi Coello and S Maspoch
Anal. Methods, 2012, Accepted Manuscript
DOI: 10.1039/C2AY26235E

The feasibility of wavelength dispersive X-ray fluorescence spectrometry for the assessment of lead concentration in animal bone powder
José A. A. Brito ,  Inês I. B. Cavaleiro ,  Tânia A. P. Fernandes and Luísa M. L. Gonçalves
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26455B

Determination of lead in animal bone powder

More articles for you to enjoy:

Novel pH sensor based on anthraquinone–ferrocene modified free standing gold nanowire array electrode
Louise Devlin ,  Mamun Jamal and Kafil Mahmood Razeeb
Anal. Methods, 2012, Accepted Manuscript
DOI: 10.1039/C2AY26264A

Combining enzymatic 18O-labeling and 2-D LC-MS/MS for study of protein interactions in primary T cells
Diana Lang ,  Sabine Anker ,  Benno Kuropka and Eberhard Krause
Anal. Methods, 2012, Accepted Manuscript
DOI: 10.1039/C2AY26298C

Detection of nitrite, iodate and bromate with Eu-POM sensor

Nitrite, iodate and bromate are commonly found in food and drinking water and they can play important roles in human health. Iodine compounds, for example, are crucial to the smooth running of the thyroid, while bromate is a by-product of water purification. However, the consumption of excessive amounts of these ions can cause serious health issues. Current methods of detecting nitrite, iodate and bromate largely rely on expensive spectroscopic equipment and time consuming chemical analysis.

Li-Hua Bi and Li-Xin Wu from Jilin University, China, have developed a novel detection method which utilises the electrochemistry and redox properties of a europium polyoxometalate (Eu-POM) sensor. The Eu-POM is electrochemically reduced, leading to luminescence quenching and a change in the solution from colourless to blue. The presence of oxidising nitrite, iodate and bromate ions reverses this process, affording discolouration and luminescence recovery. The colour change can be recycled infinitely, and measured using a UV-vis spectrometer. This sensor demonstrates a good linearity relationship between absorbance and concentration of NO₂^–, IO₃^– and BrO₃^–.

The simplicity of this method, along with high sensitivity and low detection limits, make it an attractive prospect for future use in the sensing of these ions in solution.

A novel detection of nitrite, iodate and bromate based on a luminescent polyoxometalate
Bin Wang,  Rui-Qi Meng,  Ling-Xiao Xu,  Li-Xin Wu and Li-Hua Bi
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26217G

As well as the wonderful themed papers on Cosmetic Ingredients, we also have a number of brilliant non-themed articles in this latest issue. Topics covered include water analysis, hydrogen peroxide sensing, and CN^– testing in cells.

A simple and sensitive intramolecular charge transfer fluorescent probe to detect CN⁻ in aqueous media and living cells
Mohammad Shahid and Arvind Misra
Anal. Methods, 2013, 5,
DOI: 10.1039/C2AY25921D

Release of iodine from organic matter in natural water by K₂S₂O₈ oxidation for ¹²⁹I determination
Haijun Dang, Xiaolin Hou, Per Roos and Sven P. Nielsen
Anal. Methods, 2013, 5,
DOI: 10.1039/C2AY25958C

Aqueous synthesis of Ag⁺ doped CdS quantum dots and its application in H₂O₂ sensing
Lin Lin, Yaqiong Wen, Yanxia Liang, Na Zhang and Dan Xiao
Anal. Methods, 2013, 5,
DOI: 10.1039/C2AY26063H

These papers will be free to read until January 18th.

Detection of GHB in wine

γ-Hydroxybutyrate (GHB) is an odourless, tasteless compound sold illegally as a recreational drug under various names including ‘liquid ecstasy’. However it is more widely known as a date rape drug, causing catalepsy and short term memory loss when added to drinks.  Renato Zenobi and researchers at ETH Zürich report a new application of secondary electrospray ionisation (SESI) mass spectrometry for the detection of GHB in drinks and bodily fluids. The results were found to be consistent across different mass spectrometers and matrices. Both rapid and reliable, this method has the potential to prevent crimes by detecting drugs like GHB (and the structurally related compound GBL) in the headspace of a drink before it is consumed.

This article will be free to read until January 9th. Take a look now:

In situ detection of γ-hydroxybutyrate and γ-butyrolactone in drinks by secondary electrospray ionization
Christian Berchtold, Stefan Schmid, Lukas Meier and Renato Zenobi
Anal. Methods, 2013, Advance Article
DOI: 10.1039/C2AY26009C