Chemical analysis moves on
By Julian South - 11 June 2013
Recent developments in techniques under the broad umbrella of chemical analysis have allowed us to investigate and solve problems that were previously difficult to understand. The ability to detect analytes at very low levels has brought to light potential problems that we might not even have known about. We carry out many of these new analyses at Campden BRI.
The application of fourier transform infra-red analysis spectroscopy enables us to confirm the identity of many materials. It is based on the interaction of infra-red light with chemical bonds in the material being studied, such as C–O, C–H or C–N. Illumination of a molecule will produce a spectrum of peaks, and each peak can be related to a particular type of bond. Individual spectra thus provide a 'fingerprint' of individual molecules, which can be used in the identification of incoming raw materials, determination of contamination, including deliberate adulteration (e.g. palm oil addition to virgin olive oil), and quality issues (such as sugar/acid ratio in tomatoes), as well as to identify the chemical composition of foreign bodies.
X–ray microanalysis is used to determine the elemental composition of a material. It can be used to identify the type of glass found as a foreign object in food. Combining this with a scanning electron microscope means that variations in the elemental distribution can be visualised , such as the distribution of salt and calcium phosphate crystals in cheddar cheese.
Mass spectrometry has been used in combination with gas or liquid chromatography to identify organic compounds for many years, by analysis of the fragmentation patterns of the ionised compounds. More detailed and accurate information can now be gathered by adding a second mass spectrometry step to give 'tandem mass spectrometry' and this is used to give exceptionally sensitive detection of chemical contaminants such as pesticides and mycotoxins.
Inductively coupled plasma optical emission spectrometry (ICP–OES) is used for the detection of trace metals. The inductively coupled plasma results in the emission of electromagnetic radiation at wavelengths characteristic of a particular element. The intensity of this emission is indicative of the concentration of the element within the sample. We have recently installed a new state–of–the–art machine, enabling us to improve our portfolio of trace metal analysis services.
Find out more about our Food analysis and testing activities.