This work was supported by the Ministry of Education and Science of Spain (Project CTM2006-11991) and FEDER funds.Catalá Icardo, M.; López Paz, JL.; Choves Barón, C. (2010). Tandem chemiluminescence-flow injection analysis for dimethoate determination. Luminescence. 25:235-236. https://doi.org/10.1002/bio.1217S2352362

Cicchi, S.

Del Rosso, T.

Fabbrizzi, P.

Giorgetti, E.

Margheri, G.

Muniz-Miranda, M.

Sottini, S.

English

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Luminescence

XIVth International Symposium on Luminescence Spectrometry - Recent advances of luminescence techniques in research and modern technology (ISLS 2010) Extended Abstracts

When an electromagnetic radiation interacts with a metal, the conduction electrons can be trapped in surface nanosize struc-tures giving rise to collective excitations called surface plasmons.These latter are responsible of the SERS (surface-enhanced Raman scattering)eff ect,which provides huge magnifi cation ofthe Raman signal of molecules adhering to nanostructured sur-faces of metals like silver,gold or copper.The surface plasmonresonances have also a sizeable eff ect on the fl uorescence of theligand/metal systems,increasing the excitation effi ciency neces-sary for the fl uorescence emission and producing surface-enhanced fluorescence (SEF).When an electromagnetic radiation interacts with a metal,theconduction electrons can be trapped in surface nanosize struc-tures giving rise to collective excitations called surface plasmons.These latter are responsible of the SERS (surface-enhancedRaman scattering)eff ect,which provides huge magnifi cation ofthe Raman signal of molecules adhering to nanostructured sur-faces of metals like silver,gold or copper.The surface plasmonresonances have also a sizeable eff ect on the fluorescence of theligand/metal systems,increasing the excitation effi ciency neces-sary for the fluorescence emission and producing surface-enhanced fl uorescence (SEF)

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Fluorescence and Raman scattering of sulphur-functionalized 4-amino,7-nitro-benzofurazan adsorbed on Ag and Au nanostructured surfaces

This work was supported by the Ministry of Education and Science of Spain (Project CTM2006-11991) and FEDER funds.Catalá Icardo, M.; López Paz, JL.; Choves Barón, C. (2010). Tandem chemiluminescence-flow injection analysis for dimethoate determination. Luminescence. 25:235-236. https://doi.org/10.1002/bio.12172352362

Catalá Icardo, Mónica

López Paz, José Luis

Choves Barón, Cristina

RiuNet

 Document downloaded from:  This paper must be cited as:                     The final publication is available at   Copyright http://dx.doi.org/10.1002/bio.1217http://hdl.handle.net/10251/52896Wiley: 12 monthsCatalá Icardo, M.; López Paz, JL.; Choves Barón, C. (2010). Tandem chemiluminescence-flow injection analysis for dimethoate determination. Luminescence. 25:235-236.doi:10.1002/bio.1217.Tandem chemiluminescence – flow injection analysis for dimethoate determination  M.Catalá-Icardo, J.L. López-Paz, C. Choves-Barón Instituto de investigación para la Gestión Integrada de Zonas Costeras, Universidad Politécnica de Valencia, Grao de Gandía (Valencia), Spain. E-mail: mocaic@qim.upv.es  Keywords: Chemiluminescence; flow injection analysis; dimethoate; pesticides  Introduction Dimethoate (O,Odimethyl S-methylcarbamoylmethyl phosphorodithioate) is an insecticide and acaricide that exhibits both contact and systemic activity. In spite of the fact that separative methods are generally preferred in the pesticide analysis, the low cost and simplicity provided by flow injection analysis (FIA) makes this methodology an interesting alternative. The tandem with chemiluminescent (CL) detection allows to achieve the sensitivity required for analysis at trace levels. The only CL method previously developed for dimethoate analysis, is based on reaction between ozone and the nitric oxide produced by the pyrolysis, performed in the effluent of a supercritical-fluid chromatography equipment1. The FIA method proposed is based on the direct CL generated by reaction with Ce(IV) in acid medium and greatly sensitized by hexadecylpyridinium chloride. The effect of irradiation with UV light on CL dimethoate response was investigated, and both, CL and photoinduced chemiluminescence (PICL) detection, were compared.  Experimental  Material and methods A homemade luminometer provided with a P30CWAD5 type 9125B photomultiplier (Electron Tubes) was used for CL measurements and a Gilson minipuls peristaltic pump and a rotary valve (Model 161T031, NResearch) for the flow injection manifold. The photoreactor consisted of a PTFE tube helically coiled around a 15 W low-pressure mercury lamp (Sylvania).  Optimization The preliminary experiments deal with the CL and PICL behaviour of dimethoate. The suitable oxidant was established by testing several strong oxidant systems. The best outputs were obtained with MnO4-, Ce(IV) and N-bromosuccinimide and the signals were 40, 117 and 35 % higher, respectively, when sample was previously irradiated. Next steps were performed simultaneously with and without previous irradiation, and chemical and hydrodynamic parameters were studied. The configuration for CL and PICL determinations are depicted in figure 1.             Figure 1. Manifold configurations for dimethoate determination: a) PICL manifold; Channel 1: sample at 2.1 mL min-1; Channel 2: 2.0 M NaOH at 0.5 mL min-1; Channel 3: 0.36% hexadecylpyridinium chloride at 0.5 mL min-1; Channel 4: water at 12.2 mL min-1; Channel 5: 1.15 10-3 M Ce(NH4)2(NO3)6 in 2.5 M acetic acid at 4.2 mL min-1. b) CL manifold: Channel 1´: sample at 1.6 mL min-1; Channel 2´: 0.34 M NaOH at 0.8 mL min-1; Channel 3´: 0.4% hexadecylpyridinium chloride at 0.8 mL min-1; Channel 4´: water at 14.3 mL min-1; Channel 5´: 1.8 10-3 M Ce(NH4)2(NO3)6 in water at 2.2 mL min-1: Channel 6´: 2.2 M HCl at 2.2 mL min-1.  P: peristaltic pump; PR: Photoreactor; V: injection valve; D: luminometer.   Results Analytical figures of merit were established for both, CL and PICL, systems (Table 1). In spite of PICL improves usually sensitivity and selectivity2, the best results were obtained from the native CL of dimethoate, which is greatly increased by hexadecylpyridinium chloride, achieving a detection limit of 0.05 ng mL.   CL PICL Intensity (I, kHz) vs Concentration Relation (C, g mL-1) (Dynamic range) I = 0.269 · C - 0.20 (0.5-100 g·L-1) log I = 1.70 · log C + 4.49 (0.05-1 g·mL-1) LOD (S/N=3) 0.05 ng·mL-1 10 ng·mL-1 Inter-day reproducibility (n=5) 4.5 % 1.2 % Intra-day repeatability (n=21) 2.8 % (0.01 g mL-1) 3.8 % (0.2 g mL-1) Sample throughput 86 h-1 86 h-1 Table 1. Analytical figures of merit for CL and PICL methods. 3 2 1  D V PR    P 4 5 3´ 2´1´  D V 4´ 5´    P 6´ a) b)   Acknowledgment This work was supported by the Ministry of Education and Science of Spain (Project CTM2006-11991) and FEDER funds.  References [1] H. Shi, J.T.B. Strode, L.T. Taylor, E.M. Fujinari. J. Chromatogr. A. 1996; 734(2), 303. [2] M. Catalá-Icardo, J.Martínez-Calatayud. Crit. Rev. Anal. Chem. 2008; 38(2), 118.   