Raman spectroscopy

There is a strong demand for accurate chemical measurements at very low concentration levels for testing compliance with regulatory levels and to detect contamination, especially in the air quality, food, healthcare, pharmaceutical, environmental and food industries. In particular, there is a requirement to identify and measure trace components that may be hazardous to human health and the environment. The need to perform speciation analysis on these trace contaminants is also increasing. Additionally, there is a requirement to develop new analytical techniques and instrumentation that are reproducibly able to provide quantitative analysis at ultra-trace, and even single molecule, levels.

The electrochemistry and trace analysis area aims to apply measurement science to an array of trace analysis problems, particularly within environmental matrices. This area encompasses a diverse portfolio of technologies and research in three main areas:

Electrochemistry

We focus mainly on the application of electrochemistry to analytical measurements, at the primary and end user levels, including:

• Maintaining the UK's link to primary standards of pH
• Research into the measurement of pH using primary and secondary methods
• Research into improvements in the Harned Cell methodology
• The measurement of trace concentration of ions in solution using novel designs for ion selective electrodes
• The use of stripping voltammetry for trace metals analysis

Trace Analysis

This area covers the application of a variety of measurement techniques to the assessment of trace analytes in environmental matrices, especially particulate matter in ambient air. We focus on the following:

• Development of new and robust chemical measurement methodologies, for trace level pollutants in ambient particulate matter, such as metals, polycyclic aromatic hydrocarbons and anions:
  • Ion chromatography for the measurement of anions and cations in ambient particulates
  • Atomic fluorescence techniques for the measurement of mercury vapour concentrations in ambient air
  • Inductively coupled plasma-mass spectrometry for the measurement of trace metals in ambient particulate matter (and, in particular, NPL's operation of the UK Heavy Metals Monitoring Network)
  • Gas chromatography-mass spectrometry for the measurement of organic compounds in ambient particulate matter
• Development of novel methods for screening trace analysis data

Surface Enhanced Raman Spectroscopy (SERS)

This area focuses on improving the repeatability and reproducibility of SERS and understanding the mechanisms underpinning the method. Our research is targeted at overcoming these barriers for the uptake of this technique as a powerful tool for trace analysis. This includes:

• Novel research work in SERS related to the use of structured metals surfaces as enhancing substrates
• Research into improving the reproducibility of SERS, with a view to its application as a routine trace analysis technique

References

Relevant general references:

• Brown, R J C, Milton, M J T, 'Developments in accurate and traceable chemical measurements', Chemical Society Reviews, 2007, DOI: 10.1039/b507452p
• Brown, R J C, 'The use of Zipf's law in the screening of analytical data: a step beyond Benford', Analyst, 2007, DOI: 10.1039/b618255k.
• Brown, R J C, Milton, M J T, 'Analytical techniques for trace element analysis: an overview', Trends in Analytical Chemistry, 2005, 24, (3), 266-274
• Brown, R J C, 'Benford's law and the screening of analytical data: the case of pollutant concentrations in ambient air', Analyst, 2005, 130, 1280-1285

Trace Analysis & Electrochemistry Research >>