Band broadening in solid phase reactors packed with catalyst for reactions in continuous-flow systems

Nondek, L.; Brinkman, U.A.Th.; Frei, R.W.

doi:10.1021/ac00260a006

Cited by 42 publications

(15 citation statements)

References 9 publications

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“…Since in the in-column photochemical reaction system part of the reactant (i.e., the dansylated chlorophenol) is adsorbed on the stationary phase, additional band broadening due to the reaction (reaction band broadening) may occur [14]. In the present study, band broadening in both set-ups in essentially negligible (cf.…”

Section: Chemicalsmentioning

confidence: 63%

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In-Column and Post-Column Photochemical Fluorescence Enhancement in Packed Capillary Liquid Chromatography

Jansen¹,

Vreuls²,

Heide³

et al. 1988

Journal of Liquid Chromatography

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A photochemical reaction detection system coupled with a 320-pm I.D. packed fused-silica HPLC analytical column is described. This reaction detection system does not require the addition of reagent, hence it is suitable for combination with a miniaturized analytical column. As a model system, the separation and detection of some dansylated chlorophenols was chosen. In the photochemical reactor, the main reaction product is 5-dimethylaminonaphthalene-I-sulphonic acid (dansyl-OH), which is determined by fluorescence monitoring. Both the photochemical reaction after the column and in the end part of the column ('in-column') were investigated and a comparison between the two approaches was made. In both cases, band broadening due to the photochemical reaction detection system was less than 0.1 pl. In-column detection of the photochemical reaction product was investigated in order to study the possibility of carrying out separation, derivatization and detection in the analytical column. An increase in signal-to-noise ratio of more than an order of magnitude was obtained when compared with detection after the column. INTRODUCTIO N

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Section: Chemicalsmentioning

confidence: 63%

“…Hence, the possibility of carrying out the separation, the photochemical reaction and the detection in the analytical column, thus avoiding any connection and merging column, reactor and detector into one system will be discussed. Factors influencing band broadening when a reaction is carried out on a solid phase [14] will be discussed.…”

Section: Introductionmentioning

confidence: 99%

In-Column and Post-Column Photochemical Fluorescence Enhancement in Packed Capillary Liquid Chromatography

Jansen¹,

Vreuls²,

Heide³

et al. 1988

Journal of Liquid Chromatography

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“…Reactors 1 and 5 showed signs of "reaction band-broadening", 31 and they should thus be chosen when maximum conversion efficiency is desired and band-broadening is of less importance. It should be noted from Table 1a that the physical characteristics of these two materials are so widely different that one would expect a difference in mixing and mass transfer properties.…”

Section: Resultsmentioning

confidence: 99%

Solid Phase Chemiluminescence Detection Reactors Based on in Situ Polymerized Methacrylate Materials

et al. 1996

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In situ photopolymerized macroporous poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate) materials, which were prepared in a full factorial experimental synthesis design, were investigated as supports in solid phase chemiluminescence detection reactors. The reactors based on in situ polymerized supports showed higher light generation efficiency than packed bed reactors when evaluated in a flow system based on 1,1′-oxalyldiimidazolyl peroxyoxalate chemiluminescence detection of hydrogen peroxide, with 3-aminofluoranthene (3-AFA) as the immobilized light emitter. The results were correlated with the physical characteristics of the materials, and the efficiency was found to correlate with the amount of accessible reactive groups. A lower functionalization density was found to increase the peak area sensitivity for hydrogen peroxide in the flow system. This is explained by inner filtering. The peak height sensitivities were less influenced, indicating that the total system efficiency was limited by homogeneous reaction kinetics. The introduction of a spacer to mimic "pseudosolution" conditions of the bound 3-AFA moiety was found to decrease the light generation ability.

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“…Nondek et al [125,126] significantly improved the OPA/2-ME method, by hydrolyzing carbamates at 100-120°C, in a catalytic solid-phase reactor packed with a strong anion exchanger resin. One of the post-column reagent delivery pumps is eliminated, which avoids possible mixing problems and flow pulsations.…”

Section: Labelling With Orthophthalaldehyde/2-mercaptoethanol (Opa/2-me)mentioning

confidence: 99%

“…One of the post-column reagent delivery pumps is eliminated, which avoids possible mixing problems and flow pulsations. Moreover, it suppresses band broadening, due to dilution of the analyte in the mobile phase, thus improving the sensitivity and selectivity of the method: as little as 0.1 ng of aldicarb and 0.3 ng of methomyl can be detected [126]. 22 N-methylcarbamates and their major metabolites in crop samples have been also determined using solid-phase catalysis with magnesium oxide instead of the anion exchanger resin, which minimizes band broadening [113].…”

Section: Labelling With Orthophthalaldehyde/2-mercaptoethanol (Opa/2-me)mentioning

confidence: 99%

Luminescence methods in pesticide analysis. Applications to the environment

Aaron¹,

Coly²

2000

Analusis

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DossierLuminescence spectroscopy such as the need for pretreatment procedures in the case of weakly volatile and/or thermally labile pesticides (e.g., carbamates, phenylureas and sulfonylureas). The second most utilized method is HPLC, with UV-visible absorption detectors; it remains the technique of choice for screening work.The use of luminescence techniques (especially fluorescence) for organic pesticide residue analysis has been limited by the fact that, relatively few of these compounds are strongly luminescent. However, many compounds do possess the necessary degree of aromaticity and may be converted into luminescent species using a variety of methods. Hence, two distinct cases have to be considered. (i) If the pesticide under study is luminescent, then it can be determined directly; (ii) if the pesticide is non or weakly luminescent, it can be converted into a luminescent compound using various physicochemical means, including chemical and/or photochemical reactions.Derivatization reactions constitute an important aspect of pesticide luminescence analysis since many pesticides have one or more functional groups and can be converted into more stable derivatives to successfully ensure environmental analysis. The number of papers, especially reviews [8][9][10][11][12][13] and books [14][15][16][17], in which this subject is discussed, demonstrates this increase of the derivatization use.In this review, the most important publications concerning significant advances in the luminescence methodology, instrumentation and applications to environmental analysis of pesticides will be reported. We will describe the recent available literature on direct and indirect fluorimetric methods, photochemically-induced fluorescence, photosensitized fluorescence and phosphorimetric methods used for pesticide analysis. As it will be shown, recent instrumentation, including sophisticated electronics and precise optical systems, makes luminescence a highly sensitive and selective tool for pesticide residue detection. Fluorimetric methodsAn early work on the fluorescence of pesticides has been performed in stationary solutions, (i.e., batch procedure) by

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Band broadening in solid phase reactors packed with catalyst for reactions in continuous-flow systems

Cited by 42 publications

References 9 publications

In-Column and Post-Column Photochemical Fluorescence Enhancement in Packed Capillary Liquid Chromatography

In-Column and Post-Column Photochemical Fluorescence Enhancement in Packed Capillary Liquid Chromatography

Solid Phase Chemiluminescence Detection Reactors Based on in Situ Polymerized Methacrylate Materials

Luminescence methods in pesticide analysis. Applications to the environment

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