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A rapid multiresidue method has been developed for the analysis of eight pesticides (triazines, triazinones and ureas) in environmental waters. A simple end-column electrochemical detector was used in combination with an available commercial capillary electrophoresis instrument with UV detection. The determination of these pesticides using micellar electrokinetic capillary chromatography (MEKC) with dual electrochemical and UV detection is the first time reported. In both detection systems, a linear range was obtained for the eight pesticides, concentrations lower than 5.0 Â 10 À5 mol L À1, in 0.020 mol L À1 boric acid at pH 8.3 and containing 0.025 mol L À1 of sodium dodecylsulfate, to obtain selectivity in the additional separation by micellar distribution process. Under these conditions a lower detection limit than 2.0 Â 10 À6 mol L À1 (0.15 pmol of pesticide) was achieved for the most of them. The eight pesticides are resolved in less than 14 min.

Abstract. Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1-2 km), and high spatial resolution (∼ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH 4 , H 2 S, NH 3 , NO 2 , and SO 2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions.

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Surfactants which form micelles and cyclodextrins are two of the most common forms of organized media. Surfactants are known for their ability to self-assemble in water and/or organic solvents and form normal/reverse micelles above the critical micelle concentration (CMC). Micellar solubilization in surfactant solutions has been widely exploited in analytical chemistry. The formation of inclusion compounds, by using cyclodextrins as hosts, has been also frequently used to enhance the analytical responses of analytes by incorporation of guest molecules into the cyclodextrins hydrophobic cavity [1].The first observation of room temperature phosphorescence (RTP), using a microscopically organized media, used sodium dodecylsulfate (SDS) micelles in the presence of tallium [2]. Since then, several media have been investigated to stabilize the triplet-state in fluid solution at room temperature. Normal micelles, mainly sodium dodecylsulfate [3][4][5][6], cetyltrimethylammonium bromide (CTB) [7][8][9] and Triton X-100 [10] micelles, have been used in RTP analytical applications. As an alternative to the use of normal micelles, microemulsions, formed in heptane-SDS-1-pentanol, have been also reported for RTP obtention [11][12][13][14].Cyclodextrins (CDs) can form complexes with phosphors and heavy atom containing additives and these host-guest aggregates serve to populate and stabilize the fragile tripletstate, producing characteristic room temperature phosphorescence. These inclusion complexes induce an intense phosphorescence emission which is partially insensitive to Cyclodextrins are composed of D-glucose residues joined by α(1→4) linkages. α-, β-and γ-CDs, which are made up of six, seven and eight D-glucose residues, are the most common members of a CD family. These CDs are shaped like a truncated cone with a hollow, hydrophobic cavity in which a hydrophobic guest can be incorporated.Molecular encapsulation by means of molecular inclusion complex formation offers a new approach in analytical chemistry. Generally, the inclusion complex involves the spatial entrapment of a single guest molecule in the cavity of the host molecule, without the formation of any covalent bonds. Cyclodextrins, cyclic non-reducing oligosaccharides, have been extensively used to obtain these inclusion complexes. In particular, many studies have focused on the ability of CDs to include guests of varying sizes in different stoichiometric ratios and several analytical applications of these complexes have been reported [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].It is well documented that, depending upon the host CD (i.e. α-, β-or γ-CD) and the size of the guest, different

This work reports the excellent electrocatalytic activity of carbon nanotubes paste electrodes (CNTPE) prepared by dispersion of multi-wall carbon nanotubes (MWNT) within mineral oil toward the oxidation of 3-amino-1H-1,2,4-triazole (amitrole). The quantification is performed by adsorptive stripping voltammetry (AdSV). The influence of the paste composition and surface pretreatments as well as the amitrole accumulation conditions on the adsorption and further electrooxidation of this herbicide is described. After potentiodynamic pretreatment in 0.050 M phosphate buffer pH 7.4 the amitrole oxidation signal shifts 250 mV toward more negative potential and the sensitivity increases 29 fold, demonstrating that pretreated CNTPEs are extremely useful for a highly sensitive determination of amitrole down to the sub-mM levels. The oxidation peak current is proportional to the amitrole concentration over the range from 0.8 to 7.0 mM (5 min accumulation), with a detection limit of 0.6 mM (48 mgL À1) and a precision of 4.3%, n ¼ 20. The proposed method was used for the determination of amitrole in spiked river water (Alberche River (Madrid, Spain)) and tap water samples (Madrid, Spain) at levels higher than 0.6 mM.

A rapid multiresidue method has been developed for the analysis of seven phenylurea herbicides in the presence of two s-triazines in environmental waters. A simple end-column electrochemical detector was used in combination with a commercially-available capillary electrophoresis instrument with UV detection. The determination of phenylurea pesticides using micellar electrokinetic capillary chromatography with electrochemical detection represents the first such determination that has been reported. In both detection systems, linear ranges were obtained for the seven phenylurea herbicides at concentrations lower than 2.0x10(-5) mol l(-1), in 0.020 mol l(-1) phosphoric acid at pH 7.0 and containing 0.020 mol l(-1) of sodium dodecylsulfate, in order to obtain selectivity in the additional separation by a micellar distribution process. Under these conditions a detection limit lower than 5.0x10(-6) mol l(-1) (0.25 pmol of pesticide) was achieved for most of them. The pesticides were resolved in less than 30 min.