Environmental Laboratory Long-Term Seawater Analysis has Global Significance


Since 1988, scientists from the University of Hawaii have been conducting almost monthly deep-sea research expeditions to collect water samples for subsequent laboratory analysis. Originally designed to characterise subtle long-term changes in environments that were believed to be stable, the work has revealed some surprising conclusions. For example, it has become evident that even in these quasi-stable ocean systems, gradual environmental change can often result in abrupt shifts from the equilibrium state.


An important part of the work involves the collection of nutrient samples to a depth of 4800 metres. These are then frozen for subsequent analysis in the University's laboratory with a high precision SEAL Analytical (Germany) AutoAnalyzer 3 (AA3) Segmented Flow Analyser.


The sampling site is known as 'Station ALOHA', a Long-Term Oligotrophic Habitat Assessment located 100 km north of Oahu, Hawaii as part of the Hawaii Ocean Time-series program (HOT), which is based out of the School of Ocean and Earth Science and Technology (SOEST) and receives funding from the U.S. National Science Foundation.


The HOT program provides an unprecedented historical context for refining our understanding of the often subtle linkages between ocean-climate and marine biogeochemistry. Without these time-series observations, many of the processes controlling biogeochemical cycles in the deep ocean would remain obscured by the inherent complexity of the oceanic habitat.


Systematic, long-term time-series studies of selected aquatic and terrestrial habitats have yielded significant contributions to earth and ocean sciences through the characterisation of climate trends. Important


examples include the recognition of acid rain, the documentation of increasing carbon dioxide (CO2) in the earth's atmosphere and the description of large scale ocean-atmosphere climate interactions in the equatorial Pacific Ocean.


Long time-series observations of climate-relevant variables in the ocean are extremely important because repeated oceanographic measurements are required to gain an understanding of natural processes or phenomena that exhibit slow or irregular change, as well as rapid event-driven variations that are impossible to document reliably from a single field expedition. Time-series studies are also ideally suited for the documentation of complex natural phenomena that are under the combined influence of physical, chemical and biological controls.


The oceans are known to play a central role in regulating the global concentration of CO2 in the atmosphere and it is generally believed that the world ocean has removed a significant portion of anthropogenic atmospheric CO2. It is clear therefore that a better understanding of the interactions between the atmosphere and the ocean is essential if we are to make informed decisions about how to protect the environment.


Measurements of water column chemistry, currents, optical properties, primary production, plankton community structure, and rates of particle export are made on each cruise and both inorganic and organic nutrient samples are analyzed to provide a clear picture of the water column.


The SEAL Analytical AA3 analyser is capable of analysing up to 300 tests per hour. Susan Curless has acted as the lead nutrient analyst for the HOT program from January 2005 and has employed the AA3 for nutrient analysis since that time. Susan is also one of the chief scientists of the HOT program, so when she is not out at sea organising, planning, and leading research cruises, she is in the laboratory analysing nutrient samples.


Susan also utilises the AA3 for nutrient samples collected on CMORE (Centre for Microbial Oceanography: Research and Education) cruises.


Speaking on behalf of SEAL Analytical, Stuart Smith says: "A great deal of time, effort and money goes in to the creation of seawater samples in the HOT program. Furthermore, the data that these samples provide is of global significance, so it is hardly surprising that the program chose a high performance instrument with a reputation as the world's most reliable segmented flow analyser.


"Leading seawater laboratory and research institutes use the SEAL AutoAnalyzer 3 and QuAAtro instruments because as well as being reliable laboratory instruments, these analysers are designed to provide high resolution analysis despite tough conditions onboard an oceangoing research vessel, and are in routine ship-board use from the Arctic Ocean to the Weddel Sea."


Reader Reply Card No. New Article on Pyrethroid Screening in Sediment Now Available for Download


Published in the October/November edition of International Labmate, an article from Bruker’s CAM division (USA), ‘Screening Sediment for Pyrethroid Insecticides Using GC-MS/MS’ by Bruker expert Ed George, is now available for download. The article examines how excellent sensitivity and low limits of detection (LOD) are offered by the SCION triple quadrupole (TQ) through its use of electron impact ionization (EI), tandem MS/MS and temperature vaporization injection (PTV), making it the ideal choice for the analysis of sub ppb concentrations in complex matrices.


Pyrethroids are chemically adapted from pyrethrins, which are naturally produced by chrysanthemums. Pyrethroids have been synthesized to increase their stability in sunlight. Although their use in insecticides is vital to increase food and cotton crop production as well as for mosquito control, pyrethroids are highly toxic to aquatic organisms which enter the water supply from agricultural run off. With regulatory agencies, such as the Environmental Protection Agency (EPA), developing evermore stringent regulations on levels of allowable chemicals in the environment, it is important that laboratories have highly capable instrumentation such as Bruker’s SCION TQ to meet these requirements. GC-MS/MS provides the necessary high-speed scanning in full scan mode to complete assays faster, with greater accuracy and higher sensitivity in the identification and quantitation of more compounds than previously possible. Alongside EI, tandem MS/MS and PTV, Compound-Based Scanning (CBS) software sets the SCION apart facilitating easy set-up of multiple reaction


monitoring (MRM). By optimizing scan time and duty cycle, referencing a built-in library of over 2,500 MRM transitions and 900 contaminants, automatic creation and population of the data handling table the operator is free to carry out other tasks.


“It’s great to see that the awareness and utility of GC-MS/MS are growing and the application of its uses in analytical laboratories all over the world to tackle current issues,” commented Meredith Conoley, Director of Marketing, Bruker CAM division. “Our double award winning SCION TQ’s increased levels of sensitivity and lower limits of detection with its additional design features that provide reduced signal-to-noise ratio and zero cross-talk. The SCIONs easily fit into any environmental, toxicology, food or water lab for routine pesticide analysis”.


Reader Reply Card No. Efficient Analysis of High Boiling Point Compounds


Shimadzu (Japan), one of the worldwide specialist manufacturers of analytical instrumentation, has launched the HS-20 gas chromatography headspace sampler for accurate analysis of an even wider range of volatile compounds with boiling points ranging from low to high. The HS-20 heats liquid or solid samples sealed in a container to a specific temperature, and injects the volatile compounds diffusing into the gaseous phase into a GC or a GCMS. These systems are widely used in the fields of environmental and pharmaceutical applications as well as in materials and food products analysis and forensics. The HS-20 will support these analyses particularly in testing and inspection organisations.


The unique configuration of flow lines and the oven enables the analysis of high boiling point compounds while minimising carryover. Using the electronic cooling trap, it is also possible to concentrate the headspace gas for analysis of compounds with extremely high sensitivity.


Headspace samplers enable easy analysis of volatile compounds. They are used in various fields requiring higher reliability, such as analysis of VOCs (volatile organic compounds) in the environmental and quality control applications of pharmaceuticals whereas in food products and materials control a wide range of volatile compounds with low to high boiling points has to be detected with high sensitivity in order to provide accurate qualitative and quantitative results for numerous measurement targets.


Reader Reply Card No. 66 Reader Reply Card No. 67 www.envirotech-online.com AET Annual Buyers’ Guide 2013 65 64


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