PhD BSc(Hons) (Otago)
Tel: 03 479 7913
Location: Science II 3n12
Email: rfrew@chemistry.otago.ac.nz
Main research interests
- Trace metals in natural waters
- Stable isotope geochemistry
- Paleo-chemistry
- Geochemical provenancing
Current research projects
Determining the geographical origin of food and other commodities of interest:
The geochemical composition of a natural product provides a inherent signature that can be related to its point of origin. We are currently working on developing robust tools encompassing analyses (light isotopes, trace metals and heavy isotopes), databasing and statistical interpretation. Projects on whole foods (e.g. honey, coffee, edible oils) are on-going and attention is now on deciphering the signal within complex mixtures.
Nitrogen in the oceans, fate and fluxes:
Nitrogen compounds i the ocean play an important role in sustaining primary productivity and some are implicated as potential climate modifiers. However the the controls of the rates and pathways of the cycling of nitrogen from the relatively inert N2(g) through the essential nutrients NO3 and NH4, amino acids and various gaseous oxides is not well understood. The potential of climate change underlines the importance of understanding the marine biogeochemistry of nitrogen. For example, the regions of nitrogen fixation will increase with global warming thereby enhancing the marine fixed nitrogen pool. On the other hand nitrous oxide is a significant greenhouse gas with a global warming potential 300 times that of CO2 on a molecular basis. This project applies isotopic tools to unravel the complexities of the marine nitrogen systematics.
Publications
Anh, H. L., Nhan, D. D., Frew, R., & Quynh, T. M. (2022). Application of stable isotope technique to authenticate the geographical origin of imported apple products. Journal of Radioanalytical & Nuclear Chemistry. Advance online publication. doi: 10.1007/s10967-022-08450-7
Schlieman, C. D., Wing, S. R., O'Connell-Milne, S. A., McMullin, R. M., Durante, L. M., Kolodzey, S., & Frew, R. D. (2022). Catchment modifications influence the composition of basal organic matter supporting suspension-feeding bivalves. Estuarine, Coastal & Shelf Science. Advance online publication. doi: 10.1016/j.ecss.2022.107989
Gregorčič, S. H., Ogrinc, N., Frew, R., Nečemer, M., Strojnik, L., & Zuliani, T. (2022). Reply to Horacek, M. The need to consider geochemistry when interpreting Sr-isotopes: Comment on "Gregorčič et al. The provenance of Slovenian milk using 87Sr/86Sr isotope ratios. Foods 2021, 10, 1729”. Foods, 11, 581. doi: 10.3390/foods11040581
Kalpage, M., Dissanayake, C., Diyabalanage, S., Chandrajith, R., Frew, R., & Fernando, R. (2022). Stable isotope and element profiling for determining the agroclimatic origin of cow milk within a tropical country. Foods, 11(3), 275. doi: 10.3390/foods11030275
Zhu, D., Hayman, A., Frew, R., Kebede, B., Chen, G., & Stewart, I. (2022). Milk powder extraction: Optimization of conditions for the water-soluble metabolites by proton nuclear magnetic resonance (1H-NMR). Analytical Letters, 55(1), 1-10. doi: 10.1080/00032719.2021.1907588
McComb, K., & Frew, R. (2013). Using new analytical approaches to verify the origin of honey. In P. Brereton (Ed.), New analytical approaches for verifying the origin of food. (pp. 216-242). Cambridge, UK: Woodhead. doi: 10.1533/9780857097590.3.216
Chapter in Book - Research
Sander, S. G., Hunter, K., & Frew, R. (2009). Sampling and measurements of trace metals in seawater. In O. Wurl (Ed.), Practical guidelines for the analysis of seawater. (pp. 305-327). Boca Raton, FL: CRC Press.
Chapter in Book - Research
North, J. C., & Frew, R. D. (2007). Isotopic characterisation of leachate from seven New Zealand landfills. In E. C. Lehmann (Ed.), Landfill research focus. (pp. 199-261). New York: Nova Science.
Chapter in Book - Research
Heywood, K. J., Locarnini, R. A., Frew, R. D., King, B. A., & Dennis, P. (1998). Transport and water masses of the Antarctic slope front system in the eastern Weddell sea. In S. Jacobs & R. Weiss (Eds.), Ocean, Ice and Atmosphere: Interactions at the Antartic Continential Margin. (pp. 203-214). AGU Antarctic Research Series.
Chapter in Book - Research
Dennis, P. J., Heywood, K. J., & Frew, R. D. (1997). Oxygen Isotope Studies. In R. T. Pollard & D. Smythe-Wright (Eds.), Understanding Ocean Circulation. (pp. 31-32). UK: WOCE.
Chapter in Book - Research
Anh, H. L., Nhan, D. D., Frew, R., & Quynh, T. M. (2022). Application of stable isotope technique to authenticate the geographical origin of imported apple products. Journal of Radioanalytical & Nuclear Chemistry. Advance online publication. doi: 10.1007/s10967-022-08450-7
Journal - Research Article
Kalpage, M., Dissanayake, C., Diyabalanage, S., Chandrajith, R., Frew, R., & Fernando, R. (2022). Stable isotope and element profiling for determining the agroclimatic origin of cow milk within a tropical country. Foods, 11(3), 275. doi: 10.3390/foods11030275
Journal - Research Article
Schlieman, C. D., Wing, S. R., O'Connell-Milne, S. A., McMullin, R. M., Durante, L. M., Kolodzey, S., & Frew, R. D. (2022). Catchment modifications influence the composition of basal organic matter supporting suspension-feeding bivalves. Estuarine, Coastal & Shelf Science. Advance online publication. doi: 10.1016/j.ecss.2022.107989
Journal - Research Article
Zhu, D., Hayman, A., Frew, R., Kebede, B., Chen, G., & Stewart, I. (2022). Milk powder extraction: Optimization of conditions for the water-soluble metabolites by proton nuclear magnetic resonance (1H-NMR). Analytical Letters, 55(1), 1-10. doi: 10.1080/00032719.2021.1907588
Journal - Research Article
Diyabalanage, S., Kalpage, M. D., Mohotti, D. G., Dissanayake, C. K. K., Fernando, R., Frew, R. D., & Chandrajith, R. (2021). Comprehensive assessment of essential and potentially toxic trace elements in bovine milk and their feeds in different agro-climatic zones of Sri Lanka. Biological Trace Element Research, 199, 1377-1388. doi: 10.1007/s12011-020-02242-4
Journal - Research Article
Durante, L. M., Smith, R. O., Kolodzey, S., McMullin, R. M., Salmond, N. H., Schlieman, C. D., O'Connell-Milne, S. A., Frew, R. D., Van Hale, R., & Wing, S. R. (2021). Oceanographic transport along frontal zones forms carbon, nitrogen, and oxygen isoscapes on the east coast of New Zealand: Implications for ecological studies. Continental Shelf Research, 216, 104368. doi: 10.1016/j.csr.2021.104368
Journal - Research Article
Gregorčič, S. H., Ogrinc, N., Frew, R., Nečemer, M., Strojnik, L., & Zuliani, T. (2021). The provenance of Slovenian milk using 87Sr/86Sr isotope ratios. Foods, 10(8), 1729. doi: 10.3390/foods10081729
Journal - Research Article
Sanchez, L. J., Zhu, D., Frew, R., & Kebede, B. (2021). Optimization of nuclear magnetic resonance and gas chromatography-mass spectrometry-based fingerprinting methods to characterize goat milk powder. Journal of Dairy Science, 104(1), 102-111. doi: 10.3168/jds.2020-18467
Journal - Research Article
Zhu, D., Kebede, B., McComb, K., Hayman, A., Chen, G., & Frew, R. (2021). Milk biomarkers in relation to inherent and external factors based on metabolomics. Trends in Food Science & Technology, 109, 51-64. doi: 10.1016/j.tifs.2020.12.012
Journal - Research Article
Durante, L. M., Sabadel, A. J. M., Frew, R. D., Ingram, T., & Wing, S. R. (2020). Effects of fixatives on stable isotopes of fish muscle tissue: Implications for trophic studies on preserved specimens. Ecological Applications, 30(4), e02080. doi: 10.1002/eap.2080
Journal - Research Article
Ellwood, M. J., Boyd, P. W., Cornwall, C. E., Croot, P., Currie, K. I., Frew, R. D., … Law, C., … McGraw, C. M., … Stirling, C., & Zitoun, R. (2020). Keith Hunter's legacy to marine science in New Zealand. Marine & Freshwater Research, 71(3), i-iii. doi: 10.1071/MFv71n3_ED
Journal - Research Article
Frew, R. D., Adu, T., Gault-Ringold, M., Hamidian, A., Currie, K. I., Armstrong, E., & Hunter, K. A. (2020). Strong seasonality in the cadmium and phosphate cycling at the subtropical convergence, south-eastern New Zealand. Marine & Freshwater Research, 71, 345-354. doi: 10.1071/MF19216
Journal - Research Article
Holder, P. W., Van Hale, R. J., Frew, R., George, S., & Armstrong, K. F. (2020). Natal origin of the invasive biosecurity pest, brown marmorated stink bug (Halyomorpha halys: Penatomidae), determined by dual-element stable isotope-ratio mass spectrometry. Pest Management Science, 76, 1456-1463. doi: 10.1002/ps.5659
Journal - Research Article
Wijenayake, K., Frew, R., McComb, K., Van Hale, R., & Clarke, D. (2020). Feasibility of casein to record stable isotopic variation of cow milk in New Zealand. Molecules, 25(16), 3658. doi: 10.3390/molecules25163658
Journal - Research Article
Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Changes in milk metabolome during the lactation of dairy cows based on 1H-NMR and UHPLC-QToF/MS. International Dairy Journal, 111, 104836. doi: 10.1016/j.idairyj.2020.104836
Journal - Research Article
Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Effects of the vat pasteurization process and refrigerated storage on the bovine milk metabolome. Journal of Dairy Science, 103, 2077-2088. doi: 10.3168/jds.2019-17512
Journal - Research Article
Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Impact of freeze-drying and subsequent storage on milk metabolites based on 1H NMR and UHPLC-QToF/MS. Food Control, 116, 107017. doi: 10.1016/j.foodcont.2019.107017
Journal - Research Article
Babaranti, O., Horn, S., Jowett, T., & Frew, R. (2019). Isotopic signatures in Mytilus galloprovincialis and Ulva latuca as bioindicators for assessing discharged sewage effluent in coastal waters along Otago Peninsula, New Zealand. Geology, Ecology & Landscapes, 3(1), 53-64. doi: 10.1080/24749508.2018.1485079
Journal - Research Article
McComb, K., Sarker, S., and also Hoogewerff, J., Hayman, A., & Frew, R. (2019). A δ2H Isoscape of blackberry as an example application for determining the geographic origins of plant materials in New Zealand. PLoS ONE, 14(12), e0226152. doi: 10.1371/journal.pone.0226152
Journal - Research Article
Sabadel, A. J. M., Van Oostende, N., Ward, B. B., Woodward, E. M. S., Van Hale, R., & Frew, R. D. (2019). Characterization of particulate organic matter cycling during a summer North Atlantic phytoplankton bloom using amino acid C and N stable isotopes. Marine Chemistry, 214, 103670. doi: 10.1016/j.marchem.2019.103670
Journal - Research Article
Udy, J. A., Wing, S. R., O'Connell-Milne, S. A., Durante, L. M., McMullin, R. M., Kolodzey, S., & Frew, R. D. (2019). Regional differences in supply of organic matter from kelp forests drive trophodynamics of temperate reef fish. Marine Ecology Progress Series, 621, 19-32. doi: 10.3354/meps12974
Journal - Research Article
Udy, J., Wing, S., O'Connell-Milne, S., Kolodzey, S., McMullin, R., Durante, L., & Frew, R. (2019). Organic matter derived from kelp supports a large proportion of biomass in temperate rocky reef fish communities: Implications for ecosystem-based management. Aquatic Conservation, 29, 1503-1519. doi: 10.1002/aqc.3101
Journal - Research Article
Van Hale, R., Schofield, M., Connor, M., Barker, R., & Frew, R. (2019). Stable isotope measurements to differentiate sources of monofluoroacetate in a blackmail case. Rapid Communications in Mass Spectrometry, 33, 839-847. doi: 10.1002/rcm.8416
Journal - Research Article
Wakefield, J., McComb, K., Ehtesham, E., Van Hale, R., Barr, D., Hoogewerff, J., & Frew, R. (2019). Chemical profiling of saffron for authentication of origin. Food Control, 106, 106699. doi: 10.1016/j.foodcont.2019.06.025
Journal - Research Article
Zhu, D., Hayman, A., Kebede, B., Stewart, I., Chen, G., & Frew, R. (2019). 31P NMR-based phospholipid fingerprinting of powdered infant formula. Journal of Agricultural & Food Chemistry, 67(36), 10265-10272. doi: 10.1021/acs.jafc.9b03902
Journal - Research Article
Gorman, A. R., Vennell, R., Holbrook, W. S., & Frew, R. (2018). Seismic characterization of oceanic water masses, water mass boundaries and mesoscale eddies SE of New Zealand. Journal of Geophysical Research: Oceans, 123(2), 1519-1532. doi: 10.1002/2017JC013459
Journal - Research Article
Li, Q., Yu, Z., Zhu, D., Meng, X., Pang, X., Liu, Y., Frew, R., … Chen, G. (2017). The application of NMR-based milk metabolite analysis in milk authenticity identification. Journal of the Science of Food & Agriculture, 97(9), 2875-2882. doi: 10.1002/jsfa.8118
Journal - Research Article
Li, Q., Zhao, Y., Zhu, D., Pang, X., Liu, Y., Frew, R., & Chen, G. (2017). Lipidomics profiling of goat milk, soymilk and bovine milk by UPLC-Q-Exactive Orbitrap Mass Spectrometry. Food Chemistry, 224, 302-309. doi: 10.1016/j.foodchem.2016.12.083
Journal - Research Article
Rajapaksha, D., Waduge, V., Padilla‐Alvarez, R., Kalpage, M., Rathnayake, R. M. N. P., Migliori, A., Frew, R., … Amarakoon, T. (2017). XRF to support food traceability studies: Classification of Sri Lankan tea based on their region of origin. X-Ray Spectrometry, 46(4), 220-224. doi: 10.1002/xrs.2748
Journal - Research Article
Sabadel, A. J. M., Browning, T. J., Kruimer, D., Airs, R. L., Woodward, E. M. S., Van Hale, R., & Frew, R. D. (2017). Determination of picomolar dissolved free amino acids along a South Atlantic transect using reversed-phase high-performance liquid chromatography. Marine Chemistry, 196, 173-180. doi: 10.1016/j.marchem.2017.09.008
Journal - Research Article
Wing, S. R., Gault-Ringold, M., Stirling, C. H., Wing, L. C., Shatova, O. A., & Frew, R. D. (2017). δ56Fe in seabird guano reveals extensive recycling of iron in the Southern Ocean ecosystem. Limnology & Oceanography, 62(4), 1671-1681. doi: 10.1002/lno.10524
Journal - Research Article
Li, Q., Meng, X., Zhu, D., Pang, X., Wang, K., Frew, R., & Chen, G. (2016). Determination of nonprotein nitrogen components of milk by nuclear magnetic resonance. Analytical Letters, 49(18), 2953-2963. doi: 10.1080/00032719.2016.1164180
Journal - Research Article
Nielsen, J. A., Frew, R. D., Whigham, P. A., Callaway, R. M., & Dickinson, K. J. M. (2016). Thyme travels: 15N isoscapes of Thymus vulgaris L. invasion in lightly grazed pastoral communities. Austral Ecology, 41(1), 28-39. doi: 10.1111/aec.12284
Journal - Research Article
Sabadel, A. J. M., Woodward, E. M. S., Van Hale, R., & Frew, R. D. (2016). Compound-specific isotope analysis of amino-acids: A tool to unravel complex symbiotic trophic relationships. Food Webs, 6, 9-18. doi: 10.1016/j.fooweb.2015.12.003
Journal - Research Article
Ehtesham, E., Hayman, A., Van Hale, R., & Frew, R. (2015). Influence of feed and water on the stable isotopic composition of dairy milk. International Dairy Journal, 47, 37-45. doi: 10.1016/j.idairyj.2015.02.008
Journal - Research Article
Holder, P. W., Frew, R., & Van Hale, R. (2015). The geographic origin of an intercepted biosecurity pest beetle assigned using hydrogen stable isotopes. Journal of Economic Entomology, 108(2), 834-837. doi: 10.1093/jee/tou097
Journal - Research Article
Jandrić, Z., Haughey, S. A., Frew, R. D., McComb, K., Galvin-King, P., Elliott, C. T., & Cannavan, A. (2015). Discrimination of honey of different floral origins by a combination of various chemical parameters. Food Chemistry, 189, 52-59. doi: 10.1016/j.foodchem.2014.11.165
Journal - Research Article
Muhammad, S. A., Frew, R. D., & Hayman, A. R. (2015). Compound-specific isotope analysis of diesel fuels in a forensic investigation. Frontiers in Chemistry, 3, 12. doi: 10.3389/fchem.2015.00012
Journal - Research Article
Muhammad, S. A., Hayman, A. R., Van Hale, R., & Frew, R. D. (2015). Assessing carbon and hydrogen isotopic fractionation of diesel fuel n-alkanes during progressive evaporation. Journal of Forensic Sciences, 60(S1), S56-S65. doi: 10.1111/1556-4029.12551
Journal - Research Article
Nielsen, J. A., Frew, R. D., Whigham, P. A., Callaway, R. M., & Dickinson, K. J. M. (2015). Germination and growth responses of co-occurring grass species to soil from under invasive Thymus vulgaris. Allelopathy, 35(1), 139-152.
Journal - Research Article
Nielsen, J. A., Whigham, P. A., Frew, R. D., Callaway, R. M., & Dickinson, K. J. M. (2015). Thyme and space invasion: Thymus vulgaris decreases exotic plant species diversity in Central Otago, New Zealand. Biological Invasions, 17(8), 2261-2274. doi: 10.1007/s10530-015-0872-9
Journal - Research Article
Parr, E. B., Cotter, J. D., Frew, R. D., & Rehrer, N. J. (2015). Muscle glycogen dominates females fuel usage in moderately intensive endurance exercise even in the cold. Annals of Sports Medicine & Research, 2(3), 1021.
Journal - Research Article
Sander, S. G., Tian, F., Ibisanmi, E. B., Currie, K. I., Hunter, K. A., & Frew, R. D. (2015). Spatial and seasonal variation of the iron speciation in surface waters of the Subantarctic front and the Otago Continental Shelf. Marine Chemistry, 173, 114-124. doi: 10.1016/j.marchem.2014.09.001
Journal - Research Article
Holder, P. W., Armstrong, K., Van Hale, R., Millet, M.-A., Frew, R., Clough, T. J., & Baker, J. A. (2014). Isotopes and trace elements as natal origin markers of Helicoverpa armigera: An experimental model for biosecurity pests. PLoS ONE, 9(3), e92384. doi: 10.1371/journal.pone.0092384
Journal - Research Article
Nielsen, J. A., Frew, R. D., Whigham, P. A., Callaway, R. M., & Dickinson, K. J. M. (2014). Thyme invasion and soil properties in the Central Otago region of New Zealand. Geoderma Regional, 1, 48-58. doi: 10.1016/j.geodrs.2014.08.002
Journal - Research Article