Professor Brendan Keely
Mass Spectrometry, Environmental Organic Chemistry and Geochemistry
The research activities in my group cover a broad range of topics in geochemistry, environmental chemistry, pesticide analysis, microbiology and forensic chemistry.
A unifying theme in much of the research is the development and application of improved analytical methods to give improved limits of detection and certainty in identification. Much of the work involves mass spectrometry, particularly liquid chromatography – mass spectrometry (LC-MS) and tandem mass spectrometry. Examples of some of these activities are given below:
Improved analytical methodology
Analysis of transformation products of photosynthetic pigments in the natural environment requires the use of high performance liquid chromatography (a right). Development of an improved separation method (b right) reveals the true complexity of the distributions and is a pre-requisite for the analysis of the profiles present in sediments.
Using this method we can routinely analyse sediments at cm or mm scale resolution. Studies in Antarctic sediments show that pigments are highly sensitive markers of environmental change responding, for example, to changes in relative sea level (Airs et al., 2001, Squier et al., 2002, 2005).
Identification of novel chlorophyll derivatives in sediments
Many sediments contain transformation products of chlorophyll pigments that are sensitive indicators of the nature of past environments. We have identified many novel sedimentary products from chlorophyll oxidation and from bacteriochlorophylls.
A novel series of sulfur-linked derivatives of chlorophyll (left) attest to the operation a diagenetic reaction with sulfur species and provide clear evidence that sulfur incorporation occurs at the earliest stages in the transformation pathways that affect organic compounds in nature (Squier et al., 2003, 2004).
Tandem MS of pesticides
Optimisation of the conditions for obtaining tandem mass spectra using an ion-trap instrument has enabled us to obtain highly reproducible tandem mass spectra for a wide range of analytes including quaternary ammonium pesticides (MS2 from m/z 122, right; Evans et al., 2000), organophosphorus pesticides and their metabolites (Goodwin et al., 2003, 2004) explosives (Evans et al., 2002, 2001) and drugs and drug-related species (Wickens et al., 2006). The use of the ion-trap has also allowed detailed characterisation of the fragmentation pathways of these and other organic compounds. mass spectrum of pesticide
Detection of Steroid Hormones in Cattle
The use of steroid hormones to fatten cattle is not permitted under EU legislation. Such malpractice can be detected by screening body fluids, e.g. urine, and feed for the presence of trace levels of the hormones. As part of a collaborative project (with CSL) we have been determining the multistage mass spectral behaviour (MSn) of a number of steroid hormones and their derivatives in order to facilitate their structural identification and confirmation. In order to confirm structures at the lowest levels possible we have been converting the steroids to their hydrazone derivatives. These give improved response as well as characteristic losses during tandem MS analysis (Kirk, Tarbin and Keely, 2006).
- Atmospheric pressure ionisation mass spectrometric fragmentation pathways of noscapine and papaverine revealed by multistage mass spectrometry and in-source deuterium labelling.
J R Wickens, R Sleeman and B J Keely, Rapid Communications in Mass Spectrometry, 2006, 20, 473-480.
- Evidence of late Quaternary environmental change in a continental east Antarctic lake from lacustrine sedimentary pigment distributions.
A H Squier, D A Hodgson and B J Keely, Antarctic Science, 2005, 17, 361-376.
- Structures and profiles of novel sulfur-linked chlorophyll derivatives in an Antarctic lake sediment.
A H Squier, D A Hodgson and B J Keely, Organic Geochemistry, 2004, 35, 1309-1318.
- Negative ion electrospray mass spectrometry of aminomethylphosphonic acid and glyphosate: elucidation of fragmentation mechanisms by multistage mass spectrometry incorporating in-source deuterium labelling.
L Goodwin, J R Startin, D M Goodall and B J Keely, Rapid Communications in Mass Spectrometry, 2004, 18, 37-43.
- A high resolution study of the pigment distributions in a calcite/gypsum microbial mat.
R L Airs and B J Keely, Org. Geochem, 2003, 34, 539-551.
- Tandem mass spectrometric analysis of glyphosate, glufosinate, aminomethylphosphonic acid and methylphosphinicopropionic acid.
L Goodwin, J R Startin, D M Goodall and B J Keely, Rapid Communications in Mass Spectrometry, 2003, 17, 963-969.
- Analysis of glyphosate and glufosinate by capillary electrophoresis-mass spectrometry using a sheathless microelectrospray interface.
L Goodwin, J R Startin, B J Keely and D M Goodall, Journal of Chromatography A, 2003, 1004, 107-119.
- Analysis of Pesticide Residues in Lettuce by Large Volume - Difficult Matrix Introduction - Gas Chromatography - Time of Flight Mass Spectrometry (LV-DMI-GC-TOF-MS).
K Patel, R Fussell, D M Goodall and B J Keely, Analyst, 2003, 128, 1228-1231.
- Identification of novel sulfur-containing derivatives of chlorophyll a in a Recent sediment.
A H Squier, D A Hodgson and B J Keely, Chem. Commun., 2003, 624 - 625.
- Identification of diastereomeric chlorophyll allomers by atmospheric pressure chemical ionisation liquid chromatography/tandem mass spectrometry.
J S Walker, J Chi and B J Keely, Rapid Communications in Mass Spectrometry, 2003, 17, 1125-1131.
- Atmospheric pressure chemical ionisation liquid chromatography/multistage mass spectrometry of isobaric bacteriophaeophorbide d methyl esters.
M A Wilson, S R Md Saleh, D A Hodgson and B J Keely, Rapid Communications in Mass Spectrometry, 2003, 17, 2455-2458.
- Atmospheric Pressure Chemical Ionisation Liquid Chromatography/Mass Spectrometry of Bacteriochlorophylls from Chlorobiaceae: Characteristic Fragmentations.
R L Airs and B J Keely, Rapid Communications in Mass Spectrometry, 2002, 16, 453-461.
- Atmospheric pressure chemical ionisation-normal phase-liquid chromatography-mass spectrometry and tandem mass spectrometry of chlorophyll a allomers.
J Chi, J S Walker and B J Keely, Rapid Communications in Mass Spectrometry, 2002, 16, 473-479.
- A rapid and efficient mass spectrometric method for the analysis of explosives.
C S Evans, R Sleeman, J Luke and B J Keely, Rapid Communications in Mass Spectrometry, 2002, 16, 1883-1891.
- Isotachophoretic Separation of Glyphosate, Glufosinate, AMPA and MPP Using Contactless Conductivity Detection.
L Goodwin, B J Keely, M Hannah, J R Startin and D M Goodall, Analyst, 2002,
- Sedimentary Pigments as Markers for Environmental Change in an Antarctic Lake.
A H Squier, D A Hodgson and B J Keely, Org. Geochem, 2002, 33, 1655-1665.
- Development and application of a high resolution liquid chromatographic method for the analysis of complex pigment distributions.
R L Airs, J E Atkinson and B J Keely, Journal of Chromatography A, 2001, 917, 167-177.
- Tandem mass spectrometric analysis of quaternary ammonium pesticides.
C S Evans, J R Startin, D M Goodall and B J Keely, Rapid Communications in Mass Spectrometry, 2001, 15, 699-707.
- Optimisation of ion trap parameters for the quantification of chlormequat by liquid chromatography mass spectrometry and the application in the analysis of pear extracts.
C S Evans, J R Startin, D M Goodall and B J Keely, Rapid Communications in Mass Spectrometry, 2001, 14, 112-117.
- Analysis of androgenic steroid Girard P hydrazones using multistage tandem mass spectrometry.
J M Kirk, J Tarbin and B J Keely, Rapid Communications in Mass Spectrometry, 2006, 20, 1247-1252.