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Orpington, United Kingdom

Brown R.J.C.,National Physical Laboratory United Kingdom | Pirrone N.,CNR Institute of Atmospheric Pollution Research | van Hoek C.,Dutch Standardization Institute | Horvat M.,Jozef Stefan Institute | And 5 more authors.
Accreditation and Quality Assurance | Year: 2010

A standard method for the measurement of mercury in deposition is currently being finalised by Working Group 25 of the European Committee for Standardisation's Technical Committee 264 'Air Quality', in response to the requirements of the European Union's Fourth Air Quality Daughter Directive. This paper reports the results of a field measurement programme which was undertaken to assess the uncertainty of the proposed standard method, define its working range and determine its compliance with the required data quality objectives of the Fourth Air Quality Daughter Directive. © 2010 Springer-Verlag. Source


Stockwell P.B.,PS Analytical
American Laboratory | Year: 2012

Atomic fluorescence spectrometry (AFS) is used to determine mercury in its various forms at very low levels in the environment, especially in difficult matrices such as petrochemicals. It is a spectroscopic process that is based on the absorption of radiation of a certain wavelength by an atomic vapor and subsequent radiational deactivation of the excited atoms toward the detection device. The basic layout of an AFS instrument is similar to atomic absorption spectrometry (AAS), except that the light source and detectors are placed at right angles. The system involves the coupling of the mercury analyzer with a UV cracker and associated cooling modules The sample is mixed with an oxidant stream of acidified bromide/bromate, which then passes through the UV digestion system. Samples can be analyzed without any sample pretreatment. Apart from analytical techniques, reliable data should be provided, allowing process operators to control the processes and avoid costly plant shutdowns. Source


Destro Colaco C.,Sao Paulo State University | Destro Colaco C.,Paulista University | Nozomi Marques Yabuki L.,Sao Paulo State University | Nozomi Marques Yabuki L.,Paulista University | And 8 more authors.
Talanta | Year: 2014

In this work, a device based on diffusive gradients in thin films (DGT) was evaluated for the determination of Hg(II) in river water. The DGT device was assembled with a cellulose phosphate ion exchange membrane (P81 Whatman) as a binding phase and agarose gel 1.5% (m/v) as a diffusive layer. Laboratory deployments showed that the binding of Hg2+ ([HgDGT]/ [Hgsolution]) by P81 membrane was more effective (97%) than the Chelex 100 resin (80%).The effect of ionic strength, pH and potential interfering ions on Hg binding with DGT. © 2014 Elsevier B.V. All rights reserved. Source


Brombach C.-C.,University of Aberdeen | Gajdosechova Z.,University of Aberdeen | Chen B.,PS Analytical | Brownlow A.,United Road Services | And 3 more authors.
Analytical and Bioanalytical Chemistry | Year: 2015

Mercury (Hg) is a global pollutant which occurs in different species, with methylmercury (MeHg) being the critical compound due to its neurotoxicity and bioaccumulation through the food chain. Methods for trace speciation of MeHg are therefore needed for a vast range of sample matrices, such as biological tissues, fluids, soils or sediments. We have previously developed an ultra-trace speciation method for methylmercury in water, based on a preconcentration HPLC cold vapour atomic fluorescence spectrometry (HPLC-CV-AFS) method. The focus of this work is mercury speciation in a variety of sample matrices to assess the versatility of the method. Certified reference materials were used where possible, and samples were spiked where reference materials were not available, e.g. human urine. Solid samples were submitted for commonly used digestion or extraction processes to obtain a liquid sample for injection into the analytical system. For MeHg in sediment samples, an extraction procedure was adapted to accommodate MeHg separation from high amounts of Hg2+ to avoid an overload of the column. The recovery for MeHg determination was found to be in the range of 88-104 % in fish reference materials (DOLT-2, DOLT-4, DORM-3), lobster (TORT-2), seaweed (IAEA-140/TM), sediments (ERM®-CC580) and spiked urine and has been proven to be robust, reliable, virtually matrix-independent and relatively cost-effective. Applications in the ultra-trace concentration range are possible using the preconcentration up to 200 mL, while for higher MeHg-containing samples, lower volumes can be applied. A comparison was carried out between species-specific isotope dilution gas chromatography inductively coupled plasma mass spectrometry (SSID-GC-ICP-MS) as the gold standard and HPLC-CV-AFS for biological tissues (liver, kidney and muscle of pilot whales), showing a slope of 1.008 and R 2=0.97, which indicates that the HPLC-CV-AFS method achieves well-correlated results for MeHg in biological tissues. © 2014 Springer-Verlag. Source


Brombach C.-C.,University of Aberdeen | Chen B.,PS Analytical | Corns W.T.,PS Analytical | Feldmann J.,University of Aberdeen | Krupp E.M.,University of Aberdeen
Spectrochimica Acta - Part B Atomic Spectroscopy | Year: 2015

Ultra-traces of methylmercury at the sub-ppt level can be magnified in the foodweb and is of concern. In environmental monitoring a routine robust analytical method is needed to determine methylmercury in water. The development of an analytical method for ultra-trace speciation analysis of methylmercury (MeHg) in water samples is described. The approach is based on HPLC-CV-AFS with on-line preconcentration of water samples up to 200 mL, resulting in a detection limit of 40 pg/L (ppq) for MeHg, expressed as Hg. The unit consists of an optimized preconcentration column filled with a sulfur-based sorption material, on which mercury species are preconcentrated and subsequently eluted, separated and detected via HPLC-CV-AFS (high performance liquid chromatography-cold vapor atomic fluorescence spectrometry). During the method development a type of adsorbate material, the pH dependence, the sample load rate and the carry-over were investigated using breakthrough experiments. The method shows broad pH stability in the range of pH 0 to 7, without the need for buffer addition and shows limited matrix effects so that MeHg is quantitatively recovered from sewage, river and seawater directly in the acidified samples without sample preparation. © 2014 Elsevier B.V. All rights reserved. Source

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