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Liam David Little; Vikki Amanda Carolan; Kathryn Elizabeth Allen; Laura Margaret Cole; Sarah Louise Haywood-Small. Headspace analysis of mesothelioma cell lines differentiates biphasic and epithelioid sub-types. Journal of Breath Research 2020, 14, 046011 .
AMA StyleLiam David Little, Vikki Amanda Carolan, Kathryn Elizabeth Allen, Laura Margaret Cole, Sarah Louise Haywood-Small. Headspace analysis of mesothelioma cell lines differentiates biphasic and epithelioid sub-types. Journal of Breath Research. 2020; 14 (4):046011.
Chicago/Turabian StyleLiam David Little; Vikki Amanda Carolan; Kathryn Elizabeth Allen; Laura Margaret Cole; Sarah Louise Haywood-Small. 2020. "Headspace analysis of mesothelioma cell lines differentiates biphasic and epithelioid sub-types." Journal of Breath Research 14, no. 4: 046011.
MALDI-mass spectrometry imaging (MALDI-MSI) has been shown to allow the study of protein distribution and identification directly within formalin-fixed paraffin-embedded (FFPE) tissue sections. However, direct protein identification from tissue sections remains challenging due to signal interferences and/or existing post-translational or other chemical modifications. The use of antigen retrieval (AR) has been demonstrated for unlocking proteins prior to in situ enzymatic digestion and MALDI-MSI analysis of FFPE tissue sections. In the work reported here, the identification of proline oxidation, which may occur when performing the AR protocol, is described. This facilitated and considerably increased the number of identified peptides when adding proline oxidation as a variable modification to the MASCOT search criteria. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.
Marie-Claude Djidja; Emmanuelle Claude; Peter Scriven; David W. Allen; Vikki A. Carolan; Malcolm R. Clench. Antigen retrieval prior to on-tissue digestion of formalin-fixed paraffin-embedded tumour tissue sections yields oxidation of proline residues. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2017, 1865, 901 -906.
AMA StyleMarie-Claude Djidja, Emmanuelle Claude, Peter Scriven, David W. Allen, Vikki A. Carolan, Malcolm R. Clench. Antigen retrieval prior to on-tissue digestion of formalin-fixed paraffin-embedded tumour tissue sections yields oxidation of proline residues. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics. 2017; 1865 (7):901-906.
Chicago/Turabian StyleMarie-Claude Djidja; Emmanuelle Claude; Peter Scriven; David W. Allen; Vikki A. Carolan; Malcolm R. Clench. 2017. "Antigen retrieval prior to on-tissue digestion of formalin-fixed paraffin-embedded tumour tissue sections yields oxidation of proline residues." Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 1865, no. 7: 901-906.
This study investigates the identity of two unexpected arsenic species found separately in a number of urine samples sent to the Health and Safety Executive’s Health and Safety Laboratory for arsenic speciation (arsenobetaine, AB; arsenite, As3+; arsenate, As5+; monomethylarsonic acid, MMA5+; and dimethylarsinic acid, DMA5+). Micro liquid chromatography coupled to inductively coupled plasma mass spectrometry (µLC-ICP-MS) and electrospray time of flight tandem mass spectrometry (ESI-QqTOF-MS/MS) were used to identify the two arsenic peaks by comparison to several characterized arsenicals: arsenocholine, AC; trimethyl arsine oxide, TMAO; dimethylarsenoacetate, DMAA; dimethylarsenoethanol, DMAE; thio-dimethylarsinate, thio-DMA; thio-dimethylarsenoacetate, thio-DMAA and thio-dimethylarsenoethanol, thio-DMAE. The results from both the ICP-MS and ESI-QqTOF-MS/MS investigations indicate that the unexpected arsenic species termed peak 1 was thio-DMA. While the unexpected arsenic species termed peak 2 has yet to be identified, this investigation shows that it was not AC, TMAO, DMAA, DMAE, thio-DMA, thio-DMAA or thio-DMAE. This study demonstrates the incidence of unexpected arsenic species in both routine and non-routine urine samples from both workers and hospital patients.
Elizabeth Leese; Malcolm Clench; Jackie Morton; Philip H.E. Gardiner; Vikki A. Carolan. The Investigation of Unexpected Arsenic Compounds Observed in Routine Biological Monitoring Urinary Speciation Analysis. Toxics 2017, 5, 12 .
AMA StyleElizabeth Leese, Malcolm Clench, Jackie Morton, Philip H.E. Gardiner, Vikki A. Carolan. The Investigation of Unexpected Arsenic Compounds Observed in Routine Biological Monitoring Urinary Speciation Analysis. Toxics. 2017; 5 (2):12.
Chicago/Turabian StyleElizabeth Leese; Malcolm Clench; Jackie Morton; Philip H.E. Gardiner; Vikki A. Carolan. 2017. "The Investigation of Unexpected Arsenic Compounds Observed in Routine Biological Monitoring Urinary Speciation Analysis." Toxics 5, no. 2: 12.
The analytical method outlined in this feasibility study has been used to show that trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) can be detected and measured in exhaled breath condensate (EBC) samples. EBC samples and urine samples were collected from a cohort of 58 workers occupationally exposed to hexavalent chromium compounds and 22 unexposed volunteers (control group). Levels of Cr(III) and Cr(VI) were determined in EBC samples and total chromium levels were determined in urine samples. Pre and post working week samples for both EBC and urine were collected in tandem. Total chromium in urine samples was analysed by inductively coupled plasma mass spectrometry (ICP-MS). Analysis of Cr(III) and Cr(VI) in EBC samples used a hyphenated micro liquid chromatography (μLC) system coupled to an ICP-MS. Separation was achieved using an anion exchange micro-sized column. The results showed that the occupationally exposed workers had significantly higher levels of Cr(III) and Cr(VI) in their EBC samples than the control group, as well as higher levels of total chromium in their urine samples. However, for the exposed workers no significant difference was found between pre and post working week EBC samples for either Cr(III) or Cr(VI). This study has established that Cr(III) and Cr(VI) can simultaneously be detected and measured in 'real' EBC samples and will help in understanding inhalation exposure.
Elizabeth Leese; Jackie Morton; Philip Gardiner; Vikki A. Carolan. The simultaneous detection of trivalent & hexavalent chromium in exhaled breath condensate: A feasibility study comparing workers and controls. International Journal of Hygiene and Environmental Health 2017, 220, 415 -423.
AMA StyleElizabeth Leese, Jackie Morton, Philip Gardiner, Vikki A. Carolan. The simultaneous detection of trivalent & hexavalent chromium in exhaled breath condensate: A feasibility study comparing workers and controls. International Journal of Hygiene and Environmental Health. 2017; 220 (2):415-423.
Chicago/Turabian StyleElizabeth Leese; Jackie Morton; Philip Gardiner; Vikki A. Carolan. 2017. "The simultaneous detection of trivalent & hexavalent chromium in exhaled breath condensate: A feasibility study comparing workers and controls." International Journal of Hygiene and Environmental Health 220, no. 2: 415-423.
A method development study describing the first simultaneous determination of Cr(III) and Cr(VI) in an exhaled breath condensate sample.
Elizabeth Leese; Vikki A. Carolan; Jackie Morton; Philip H. E. Gardiner. Development of a method for the simultaneous detection of Cr(iii) and Cr(vi) in exhaled breath condensate samples using μLC-ICP-MS. Journal of Analytical Atomic Spectrometry 2016, 31, 924 -933.
AMA StyleElizabeth Leese, Vikki A. Carolan, Jackie Morton, Philip H. E. Gardiner. Development of a method for the simultaneous detection of Cr(iii) and Cr(vi) in exhaled breath condensate samples using μLC-ICP-MS. Journal of Analytical Atomic Spectrometry. 2016; 31 (4):924-933.
Chicago/Turabian StyleElizabeth Leese; Vikki A. Carolan; Jackie Morton; Philip H. E. Gardiner. 2016. "Development of a method for the simultaneous detection of Cr(iii) and Cr(vi) in exhaled breath condensate samples using μLC-ICP-MS." Journal of Analytical Atomic Spectrometry 31, no. 4: 924-933.
5,6-Dimethylxanthenone-4-acetic acid (DMXAA) is a low molecular weight drug of the flavonoid group, which has an anti-vascular effect in tumours causing endothelial cell apoptosis and activation of cytokines. Flavonoid-based compounds have been reported to lead to an upregulation in the expression of lysophosphatidylcholines (LPC)-type lipids in solid tumours. A study employing TLC/MALDI-MS and MALDI-MS imaging to examine LS174T colorectal adenocarcinoma xenografts following administration of DMXAA has been conducted into this effect.
Afnan Batubara; Vikki A Carolan; Paul M. Loadman; Chris Sutton; Steve D. Shnyder; Malcolm R. Clench. Thin-layer chromatography/matrix-assisted laser desorption/ionisation mass spectrometry and matrix-assisted laser desorption/ionisation mass spectrometry imaging for the analysis of phospholipids in LS174T colorectal adenocarcinoma xenografts treated with. Rapid Communications in Mass Spectrometry 2015, 29, 1288 -1296.
AMA StyleAfnan Batubara, Vikki A Carolan, Paul M. Loadman, Chris Sutton, Steve D. Shnyder, Malcolm R. Clench. Thin-layer chromatography/matrix-assisted laser desorption/ionisation mass spectrometry and matrix-assisted laser desorption/ionisation mass spectrometry imaging for the analysis of phospholipids in LS174T colorectal adenocarcinoma xenografts treated with. Rapid Communications in Mass Spectrometry. 2015; 29 (14):1288-1296.
Chicago/Turabian StyleAfnan Batubara; Vikki A Carolan; Paul M. Loadman; Chris Sutton; Steve D. Shnyder; Malcolm R. Clench. 2015. "Thin-layer chromatography/matrix-assisted laser desorption/ionisation mass spectrometry and matrix-assisted laser desorption/ionisation mass spectrometry imaging for the analysis of phospholipids in LS174T colorectal adenocarcinoma xenografts treated with." Rapid Communications in Mass Spectrometry 29, no. 14: 1288-1296.
Tumour vasculature is notoriously sinusoidal and leaky, and is hence susceptible to vascular disruption. Microtubule destabilising drugs such as the combretastatins form the largest group of tumour vascular disrupting agents and cause selective shutdown of tumour blood flow within minutes to hours, leading to secondary tumour cell death. Targeting the tumour vasculature is a proven anticancer strategy but early treatment response biomarkers are required for personalising treatment planning. Protein induction following treatment with combretastatin A4-phosphate was examined in a mouse fibrosarcoma model (fs188), where tumour cells express only the matrix-bound isoform of vascular endothelial growth factor A (VEGF188). These tumours are relatively resistant to vascular disruption by combretastatin A4-phosphate and hence a study of protein induction following treatment could yield insights into resistance mechanisms. The distribution of a number of proteins induced following treatment were visualised by MALDI-mass spectrometry imaging. Responses identified were validated by LC-ESI-MS/MS and immunohistochemical staining. Significant changes in proteins connected with necrosis, cell structure, cell survival and stress-induced molecular chaperones were identified. Protein-protein interactions were identified using STRING 9.0 proteomic network software. These relationship pathways provided an insight into the activity of the active tumour milieu and a means of linking the identified proteins to their functional partners.
Laura M. Cole; Joanne E. Bluff; Vikki A. Carolan; Martyn N. Paley; Gillian M. Tozer; Malcolm R. Clench. MALDI-MSI and label-free LC-ESI-MS/MS shotgun proteomics to investigate protein induction in a murine fibrosarcoma model following treatment with a vascular disrupting agent. PROTEOMICS 2014, 14, 890 -903.
AMA StyleLaura M. Cole, Joanne E. Bluff, Vikki A. Carolan, Martyn N. Paley, Gillian M. Tozer, Malcolm R. Clench. MALDI-MSI and label-free LC-ESI-MS/MS shotgun proteomics to investigate protein induction in a murine fibrosarcoma model following treatment with a vascular disrupting agent. PROTEOMICS. 2014; 14 (7):890-903.
Chicago/Turabian StyleLaura M. Cole; Joanne E. Bluff; Vikki A. Carolan; Martyn N. Paley; Gillian M. Tozer; Malcolm R. Clench. 2014. "MALDI-MSI and label-free LC-ESI-MS/MS shotgun proteomics to investigate protein induction in a murine fibrosarcoma model following treatment with a vascular disrupting agent." PROTEOMICS 14, no. 7: 890-903.
Hypoxia is a common feature observed in solid tumours. It is a target of interest in oncology as it has been found to be closely associated with tumour progression, metastasis and aggressiveness and confers resistance to a variety of chemotherapeutic agents as well as radiotherapy. AQ4N, also known as banoxatrone or 1,4-bis-[2-(dimethylamino-Noxide) ethyl]amino-5,8-dihydroxyanthracene-9,10-dione is a very promising bioreductive prodrug. This paper, describes an application of MALDI-MSI combined with ion mobility separation and an "on-tissue" bottom up proteomic strategy to obtain proteomic data from AQ4N dosed tumour xenograft tissue sections. These data are then correlated with the drug distribution determined also using MALDI-ion mobility separation-mass spectrometry imaging (MALDI-IMS-MSI). PCA-DA and OPLS-DA have been used to compare treated and untreated xenografts and of note is the marked increase in expression of Histone H3.
Marie-Claude Djidja; Simona Francese; Emmanuelle Claude; Paul Loadman; Chris Sutton; Steve Shynder; Patricia Cooper; Laurence H Patterson; Vikki A Carolan; Malcolm R. Clench. Targeting of Hypoxia in AQ4N-treated Tumour Xenografts by MALDIIon Mobility Separation-Mass Spectrometry Imaging. Current Analytical Chemistry 2013, 9, 212 -225.
AMA StyleMarie-Claude Djidja, Simona Francese, Emmanuelle Claude, Paul Loadman, Chris Sutton, Steve Shynder, Patricia Cooper, Laurence H Patterson, Vikki A Carolan, Malcolm R. Clench. Targeting of Hypoxia in AQ4N-treated Tumour Xenografts by MALDIIon Mobility Separation-Mass Spectrometry Imaging. Current Analytical Chemistry. 2013; 9 (2):212-225.
Chicago/Turabian StyleMarie-Claude Djidja; Simona Francese; Emmanuelle Claude; Paul Loadman; Chris Sutton; Steve Shynder; Patricia Cooper; Laurence H Patterson; Vikki A Carolan; Malcolm R. Clench. 2013. "Targeting of Hypoxia in AQ4N-treated Tumour Xenografts by MALDIIon Mobility Separation-Mass Spectrometry Imaging." Current Analytical Chemistry 9, no. 2: 212-225.
Not availablePaul J. Trim, Marie-Claude Djidja, Tasneem Muharib, Laura M. Cole, Bryn Flinders, Vikki A. Carolan, Simona Francese, Malcolm R. Clenc
Paul J. Trim; Marie-Claude Djidja; Tasneem Muharib; Laura M. Cole; Bryn Flinders; Vikki A. Carolan; Simona Francese; Malcolm R. Clench. Instrumentation and software for mass spectrometry imaging—Making the most of what you've got. Journal of Proteomics 2012, 75, 4931 -4940.
AMA StylePaul J. Trim, Marie-Claude Djidja, Tasneem Muharib, Laura M. Cole, Bryn Flinders, Vikki A. Carolan, Simona Francese, Malcolm R. Clench. Instrumentation and software for mass spectrometry imaging—Making the most of what you've got. Journal of Proteomics. 2012; 75 (16):4931-4940.
Chicago/Turabian StylePaul J. Trim; Marie-Claude Djidja; Tasneem Muharib; Laura M. Cole; Bryn Flinders; Vikki A. Carolan; Simona Francese; Malcolm R. Clench. 2012. "Instrumentation and software for mass spectrometry imaging—Making the most of what you've got." Journal of Proteomics 75, no. 16: 4931-4940.
Pesticides are widely used in agriculture to control weeds, pests and diseases. Successful control is dependent on the compound reaching the target site within the organism after spray or soil application. Conventional methods for determining uptake and movement of herbicides and pesticides include autoradiography, liquid scintillation and chromatographic techniques such as high-performance liquid chromatography (HPLC). Autoradiography using radiolabelled compounds provides the best indication of a compound's movement within the plant system. Autoradiography is an established technique but it relies on the synthesis of radiolabelled compounds. The distribution of four sulfonylurea herbicides in sunflower plants has been studied 24 h after foliar application. The use of matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) images of protonated molecules and fragment ions (resulting from fragmentation at the urea bond within the sulfonylurea herbicides) has provided evidence for translocation above and below the application point. The translocation of nicosulfuron and azoxystrobin within the same plant system has also been demonstrated following their application to the plant stem. This study provides evidence that MALDI-MSI has great potential as an analytical technique to detect and assess the foliar, root and stem uptake of agrochemicals, and to reveal their distribution through the plant once absorbed and translocated.
David M. G. Anderson; Vikki A. Carolan; Susan Crosland; Kate R. Sharples; Malcolm R. Clench. Examination of the translocation of sulfonylurea herbicides in sunflower plants by matrix-assisted laser desorption/ionisation mass spectrometry imaging. Rapid Communications in Mass Spectrometry 2010, 24, 3309 -3319.
AMA StyleDavid M. G. Anderson, Vikki A. Carolan, Susan Crosland, Kate R. Sharples, Malcolm R. Clench. Examination of the translocation of sulfonylurea herbicides in sunflower plants by matrix-assisted laser desorption/ionisation mass spectrometry imaging. Rapid Communications in Mass Spectrometry. 2010; 24 (22):3309-3319.
Chicago/Turabian StyleDavid M. G. Anderson; Vikki A. Carolan; Susan Crosland; Kate R. Sharples; Malcolm R. Clench. 2010. "Examination of the translocation of sulfonylurea herbicides in sunflower plants by matrix-assisted laser desorption/ionisation mass spectrometry imaging." Rapid Communications in Mass Spectrometry 24, no. 22: 3309-3319.
Matrix-Assisted Laser Desorption/Ionisation Mass Spectrometry Imaging (MALDI MSI) has been used to directly analyse a range of tablets in order to assess the homogeneity of the active drug compound throughout the excipients contained within the tablets studied. The information gained from the imaging experiments can be used to improve and gain a greater understanding of the manufacturing process; such knowledge will enable improvements in finished product quality to make safer and more efficacious tablet formulations. Commercially available and prescription tablet formulations have been analysed, including aspirin, paracetamol, sildenafil citrate (Viagra(R)) and a batch of tablets in development (tablet X: placebo; 1 mg; 3 mg and 6 mg). MALDI MSI provides semi-quantitative information that is related to ion abundance, therefore Principal Component Analysis (PCA), a multivariate analysis technique, has been used to differentiate between tablets containing different amounts of active drug ingredient. Aspects of sample preparation have also been investigated with regard to tablet shape and texture. The results obtained indicate that MALDI MSI can be used effectively to analyse the spatial distribution of the active pharmaceutical component (API) in pharmaceutical tablet formulations.
Caroline J. Earnshaw; Vikki A. Carolan; Don S. Richards; Malcolm R. Clench. Direct analysis of pharmaceutical tablet formulations using matrix-assisted laser desorption/ionisation mass spectrometry imaging. Rapid Communications in Mass Spectrometry 2010, 24, 1665 -1672.
AMA StyleCaroline J. Earnshaw, Vikki A. Carolan, Don S. Richards, Malcolm R. Clench. Direct analysis of pharmaceutical tablet formulations using matrix-assisted laser desorption/ionisation mass spectrometry imaging. Rapid Communications in Mass Spectrometry. 2010; 24 (11):1665-1672.
Chicago/Turabian StyleCaroline J. Earnshaw; Vikki A. Carolan; Don S. Richards; Malcolm R. Clench. 2010. "Direct analysis of pharmaceutical tablet formulations using matrix-assisted laser desorption/ionisation mass spectrometry imaging." Rapid Communications in Mass Spectrometry 24, no. 11: 1665-1672.
Matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) has been used to image the distribution of the pesticide nicosulfuron (2-[[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]aminosulfonyl]-N,N-dimethyl-3-pyridinecarboxamide) in plant tissue using direct tissue imaging following root and foliar uptake. Sunflower plants inoculated with nicosulfuron were horizontally sectioned at varying distances along the stem in order to asses the extent of translocation; uptake via the leaves following foliar application to the leaves and uptake via the roots from a hydroponics system were compared. An improved sample preparation methodology, encasing samples in ice, allowed sections from along the whole of the plant stem from the root bundle to the growing tip to be taken. Images of fragment ions and alkali metal adducts have been generated that show the distribution of the parent compound and a phase 1 metabolite in the plant. Positive and negative controls have been included in the images to confirm ion origin and prevent false-positive results which could originate from endogenous compounds present within the plant tissue.
David M. G. Anderson; Vikki A. Carolan; Susan Crosland; Kate R. Sharples; Malcolm R. Clench. Examination of the distribution of nicosulfuron in sunflower plants by matrix-assisted laser desorption/ionisation mass spectrometry imaging. Rapid Communications in Mass Spectrometry 2009, 23, 1321 -1327.
AMA StyleDavid M. G. Anderson, Vikki A. Carolan, Susan Crosland, Kate R. Sharples, Malcolm R. Clench. Examination of the distribution of nicosulfuron in sunflower plants by matrix-assisted laser desorption/ionisation mass spectrometry imaging. Rapid Communications in Mass Spectrometry. 2009; 23 (9):1321-1327.
Chicago/Turabian StyleDavid M. G. Anderson; Vikki A. Carolan; Susan Crosland; Kate R. Sharples; Malcolm R. Clench. 2009. "Examination of the distribution of nicosulfuron in sunflower plants by matrix-assisted laser desorption/ionisation mass spectrometry imaging." Rapid Communications in Mass Spectrometry 23, no. 9: 1321-1327.
Bioprosthetic heart valve tissue and associated calcification were studied in their natural state, using environmental scanning electron microscopy (ESEM). Energy dispersive X-ray micro-analysis, X-ray diffraction, Fourier-transform infrared and Raman spectroscopy were used to characterize the various calcific deposits observed with ESEM. The major elements present in calcified valves were also analyzed by inductively coupled plasma-optical emission spectroscopy. To better understand the precursor formation of the calcific deposits, results from the elemental analyses were statistically correlated. ESEM revealed the presence of four broad types of calcium phosphate crystal morphology. In addition, two main patterns of organization of calcific deposits were observed associated with the collagen fibres. Energy dispersive X-ray micro-analysis identified the crystals observed by ESEM as salts containing mainly calcium and phosphate with ratios from 1.340 (possibly octacalcium phosphate, which has a Ca/P ratio of 1.336) to 2.045 (possibly hydroxyapatite with incorporation of carbonate and metal ion contaminants, such as silicon and magnesium, in the crystal lattice). Raman and fourier-transform infrared spectroscopy also identified the presence of carbonate and the analyses showed spectral features very similar to a crystalline hydroxyapatite spectrum, also refuting the presence of precursor phases such as beta-tricalcium phosphate, octacalcium phosphate and dicalcium phosphate dihydrate. The results of this study raised the possibility of the presence of precursor phases associated with the early stages of calcification.
Christophe Delogne; Patricia V Lawford; Steven M Habesch; Vikki A Carolan. Characterization of the calcification of cardiac valve bioprostheses by environmental scanning electron microscopy and vibrational spectroscopy. Journal of Microscopy 2007, 228, 62 -77.
AMA StyleChristophe Delogne, Patricia V Lawford, Steven M Habesch, Vikki A Carolan. Characterization of the calcification of cardiac valve bioprostheses by environmental scanning electron microscopy and vibrational spectroscopy. Journal of Microscopy. 2007; 228 (1):62-77.
Chicago/Turabian StyleChristophe Delogne; Patricia V Lawford; Steven M Habesch; Vikki A Carolan. 2007. "Characterization of the calcification of cardiac valve bioprostheses by environmental scanning electron microscopy and vibrational spectroscopy." Journal of Microscopy 228, no. 1: 62-77.
Brendan Prideaux; Sally J. Atkinson; Vikki A. Carolan; Jacqueline Morton; Malcolm R. Clench. Sample preparation and data interpretation procedures for the examination of xenobiotic compounds in skin by indirect imaging MALDI-MS. International Journal of Mass Spectrometry 2007, 260, 243 -251.
AMA StyleBrendan Prideaux, Sally J. Atkinson, Vikki A. Carolan, Jacqueline Morton, Malcolm R. Clench. Sample preparation and data interpretation procedures for the examination of xenobiotic compounds in skin by indirect imaging MALDI-MS. International Journal of Mass Spectrometry. 2007; 260 (2-3):243-251.
Chicago/Turabian StyleBrendan Prideaux; Sally J. Atkinson; Vikki A. Carolan; Jacqueline Morton; Malcolm R. Clench. 2007. "Sample preparation and data interpretation procedures for the examination of xenobiotic compounds in skin by indirect imaging MALDI-MS." International Journal of Mass Spectrometry 260, no. 2-3: 243-251.
Isocyanates are an important class of compounds in occupational hygiene monitoring due mainly to their behaviour as respiratory sensitisers. Here, we demonstrate the application of matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) and MALDI tandem mass spectrometry (MS-MS) to the analysis of derivatised isocyanate monomers and prepolymers. The aim of the work has been to gauge the selectivity obtainable from the direct analysis of isocyanate mixtures without prior separation. Monomeric and prepolymeric isocyanate mixtures were analysed as their 1-(2-methoxyphenyl) piperazine derivatives and the potential of MALDI time-of-flight (ToF)-MS for an NCO monitoring program was assessed. The results obtained demonstrated the possibility of direct mixture analysis by this method. MALDI-MS-MS was used for the elucidation of fragment structures in the prepolymer samples. The developed methodology was then applied to the analysis of swabs from an occupational hygiene monitoring scheme and enabled the identification of the isocyanate species detected.
Karen E. Warburton; Malcolm R. Clench; Michael J. Ford; John White; Duncan A. Rimmer; Vikki A. Carolan. Characterisation of Derivatised Monomeric and Prepolymeric Isocyanates by Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry and Structural Elucidation by Tandem Mass Spectrometry. European Journal of Mass Spectrometry 2005, 11, 565 -574.
AMA StyleKaren E. Warburton, Malcolm R. Clench, Michael J. Ford, John White, Duncan A. Rimmer, Vikki A. Carolan. Characterisation of Derivatised Monomeric and Prepolymeric Isocyanates by Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry and Structural Elucidation by Tandem Mass Spectrometry. European Journal of Mass Spectrometry. 2005; 11 (6):565-574.
Chicago/Turabian StyleKaren E. Warburton; Malcolm R. Clench; Michael J. Ford; John White; Duncan A. Rimmer; Vikki A. Carolan. 2005. "Characterisation of Derivatised Monomeric and Prepolymeric Isocyanates by Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry and Structural Elucidation by Tandem Mass Spectrometry." European Journal of Mass Spectrometry 11, no. 6: 565-574.
A review of the literature shows that a variety of washing procedures to remove external contamination from hair have been proposed, but as yet no standardised procedures are available. In this study, methods for the pre-treatment and determination of antimony, arsenic, cadmium, chromium, lead, mercury and selenium in human hair by inductively coupled plasma mass spectrometry (ICP-MS) are developed. Investigations of various washing procedures to remove external contaminants show that in unexposed hair samples cadmium, lead and mercury are significantly removed from hair using a 0.1 M HCl wash, with 87, 73 and 5%, respectively being washed-off. The removal of antimony, arsenic and chromium from unexposed hair is, however, more efficient with 1% (v/v) sodium lauryl sulphate (SLS), with 43, 40 and 13% of each element, respectively being washed-off. Selenium is not removed from the hair by any of the washing methods studied. For the digestion of hair samples a digestion mixture of nitric acid and hydrogen peroxide is used. Experiments with simulated sweat spiked with each of these elements show that exogenously bound chromium, cadmium and lead are removed after washing with 0.1 M HCl. In contrast, antimony, arsenic, selenium and mercury irreversibly bind and, thus, are not removed with any of the washing solutions investigated. This work also compares hair levels of these elements in an unexposed and exposed group using the method developed.
Jackie Morton; Vikki A Carolan; Philip Gardiner. Removal of exogenously bound elements from human hair by various washing procedures and determination by inductively coupled plasma mass spectrometry. Analytica Chimica Acta 2002, 455, 23 -34.
AMA StyleJackie Morton, Vikki A Carolan, Philip Gardiner. Removal of exogenously bound elements from human hair by various washing procedures and determination by inductively coupled plasma mass spectrometry. Analytica Chimica Acta. 2002; 455 (1):23-34.
Chicago/Turabian StyleJackie Morton; Vikki A Carolan; Philip Gardiner. 2002. "Removal of exogenously bound elements from human hair by various washing procedures and determination by inductively coupled plasma mass spectrometry." Analytica Chimica Acta 455, no. 1: 23-34.
Inorganic and methylmercury content in human hair has previously been determined using different analytical techniques for each species. In this study a single method, allowing the separation and determination of mercury species in human hair, is developed. Using a HPLC-ICP-MS system it is possible to separate inorganic and methylmercury in hair, without any modifications to the existing instrumentation. The results showed that in order to determine methylmercury as well as inorganic mercury the hair sample must be cold digested with 2 ml of concentrated nitric acid plus 1 ml of hydrogen peroxide and that a minimum of 0.1 g hair is required. Hair washing procedures are also investigated to remove exogenously bound species. It is seen that when hair is soaked with simulated sweat solution containing both inorganic and methylmercury and then washed with 0.1 M HCl all the methylmercury, both existing and spiked, can be removed from the hair sample. However, only 65% of the spiked inorganic mercury can be removed by washing with 0.1 M HCl, the rest being irreversibly bound to the hair.
Jackie Morton; Vikki A. Carolan; Philip Gardiner. The speciation of inorganic and methylmercury in human hair by high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry 2002, 17, 377 -381.
AMA StyleJackie Morton, Vikki A. Carolan, Philip Gardiner. The speciation of inorganic and methylmercury in human hair by high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry. 2002; 17 (4):377-381.
Chicago/Turabian StyleJackie Morton; Vikki A. Carolan; Philip Gardiner. 2002. "The speciation of inorganic and methylmercury in human hair by high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry." Journal of Analytical Atomic Spectrometry 17, no. 4: 377-381.