Analyst Blog

Hot off the press: Eman Frag and colleagues describe the development of screen-printed (SPE) and carbon paste (CPE) sensors for the rapid and sensitive quantification of naphazoline hydrochloride (NPZ) in pharmaceutical formulations.

Construction and performance characterization of screen printed and carbon paste ion selective electrodes for potentiometric determination of naphazoline hydrochloride in pharmaceutical preparations
Eman Y. Z. Frag, Gehad G. Mohamed, F. A. Nour El-Dien and Marwa E. Mohamed
Analyst, 2011, Advance Article
DOI: 10.1039/C0AN00343C

Terephthalate as a probe for photochemically generated hydroxyl radical

Terephthalate picks up an OH radical to form fluorescent hydroxyterephthalate

Sarah E. Page, William A. Arnold and Kristopher McNeill, J. Environ. Monit., 2010, 12, 1658
DOI: 10.1039/c0em00160k

A sensitive probe to monitor hydroxyl radicals in water has been developed by a team of Swiss and US scientists.
Current hydroxyl radical probes, such as benzoic acid, often have limited sensitivity, require long irradiation times or high concentrations of the probe, which can affect the sample.  Now Kristopher McNeill at the Swiss Federal Institute of Technology (ETH) in Zurich and colleagues at the University of Minnesota in Minneapolis have discovered that terephthalate is a more sensitive probe for hydroxyl radicals in aquatic environments.

Read Rachel Cooper’s full news article at Highlights in Chemical Technology.

Vitamin D and its metabolites have an important role in our body's health

US researchers have developed a nanotechnology-based test to detect the important vitamin D metabolite calcitriol, the deficiency of which is an indicator of kidney failure.

Competitive surface-enhanced Raman scattering assay for the 1,25-dihydroxy metabolite of vitamin D3

Eric J. Dufek, Brian Ehlert, Michael C. Granger, Tanya M. Sandrock, Samuel L. Legge, Mark G. Herrmann, A. Wayne Meikle and Marc D. Porter, Analyst, 2010
DOI: 10.1039/c0an00354a

Marc Porter and colleagues at the University of Utah in Salt Lake City have developed a test based on the use of surface enhanced Raman scattering (SERS) combined with gold nanoparticles. This new technique requires a much smaller sample volume and has no radioactive waste compared to previous approaches.

“This paper is a very nice example of the use of SERS for the detection of metabolites in clinically relevant samples,” comments Karen Faulds, at the Centre of Molecular Nanometrology in Strathclyde, UK.

Read Rebecca Brodie’s news story at Highlights in Chemical Biology or peruse the article in full in Analyst.

Carbon-modified zinc nanorod array has impoved sensing ability

Chinese scientists have developed a highly efficient and chemically stable hydrazine sensor using carbon modified zinc oxide nanorods.  Hydrazine is highly neurotoxic and carcinogenic and can cause severe damage to the liver, lungs and kidneys.  It is used extensively in industry, and for safety considerations a reliable hydrazine sensor is highly desirable.

To find out why this new sensor is special, read Jacob Bush’s news article at Highlights in Chemical Science or access the full article via Dalton Transactions:

C@ZnO nanorod array-based hydrazine electrochemical sensor with improved sensitivity and stability
Jinping Liu, Yuanyuan Li, Jian Jiang and Xintang Huang
Dalton Trans., 2010, Advance Article
DOI: 10.1039/C0DT00258E

Pressing the buttons allows the device to be programmed for specific tests

George Whitesides and colleagues at Harvard University have developed a paper-based microfluidic device that can be programmed to carry out any test the user wants.

Read the article via the Lab on a Chip homepage.

Devices made from simple materials such as paper have great potential in developing countries, as they are cheap and easy to use.  The paper is soaked in a polymer solution and cured using light to create a network of channels.

Whitesides’ new programmable 3D device can be activated using the humble ballpoint pen.

To find out how, and also why it ‘brings another layer of sophistication to microfluidic devices’, read David Barden’s full story at Highlights in Chemical Technology.

Inhibiting acetylcholinesterase alters the growth of nanoparticles causing a colour change

A paper-based colorimetric dipstick bioassay that can detect low levels of pesticides has been developed by John Brennan and colleagues at McMaster University in Hamilton, Canada.

You can access the paper via the Analyst homepage.

Organophosphate pesticides can be toxic to both humans and animals as they inhibit important enzymes such as acetylcholinesterase (AChE) in the nervous system.  They are still in widespread use so there is a need for a simple method to detect their residues.  Now, Brennan’s team has created a gold nanoparticle-based dipstick test to identify inhibitors of the acetylcholinesterase enzyme that would be easy to use for in-field applications.

Brennan says he hopes to develop this system by ‘integrating the various reagents involved in the assay into a single lateral flow device, which should avoid the need for adding external reagents’.  His group are also ‘investigating other enzymes that are known to support catalytic growth of gold nanoparticles to further evaluate this sensor platform’.

To read the full story, head to Highlights in Chemical Technology.