Large-Volume Direct Injection for Determining Naphthalene Derivative Pesticides in Water Using a Restricted-Access Medium Column in RPLC-LC with Fluorescence Detection

Galera, M. Martı́nez; Vázquez, P. Parrilla; Vidal, José Luis Martı́nez; Fernández, José Martínez; Gómez, Jesús

doi:10.1365/s10337-004-0401-y

Cited by 11 publications

(2 citation statements)

References 31 publications

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“…It is possible that in citrus, caryophyllene production is particularly elevated by T. leucotreta herbivory on fruit as a defence against its parasitoid (Smith et al 2012). The repellence and toxic effect of naphthalene has been reported by many studies (Daisy et al 2002;Galera et al 2004). It was therefore not surprising that A. bishopi parasitoids were repelled by this compound.…”

Section: Discussionmentioning

confidence: 99%

Agathis bishopi (Hymenoptera: Braconidae) as a Potential Tool for Detecting Oranges Infested with Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

et al. 2015

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In South Africa, Thaumatotibia leucotreta is a key pest of citrus impacting its production and trade. Detection of newly infested fruit by visual inspection is challenging and poses a risk of packing infested with healthy fruit for export. Agathis bishopi is a larval endoparasitoid of T. leucotreta, attacking early larval instars. Understanding how A. bishopi parasitoids locate fruit infested with their host is of interest for developing an efficient detector for T. leucotreta infested fruit. The response of female adult A. bishopi parasitoids to olfactory and visual cues associated with T. leucotreta infested fruit were evaluated using a Y-tube olfactometer and flight tunnel. Agathis bishopi parasitoids were strongly attracted to infested fruit over healthy fruit, either when only olfactory or combinations of visual and olfactory cues were offered. Among the four synthetic compounds tested, D-limonene and ocimene elicited a strong attraction to parasitoids with response rates of 92 % and 72 % respectively. A blend of four synthetic compounds simulating T. leucotreta infested fruit odour equally elicited strong attraction to parasitoids (84 % response rate). Attraction of parasitoids to infested fruit cues was heightened by prior experience, suggesting the occurrence of associative learning. Results from this study indicate that A. bishopi parasitoids mainly rely on olfactory cues in host habitat location and that D-limonene and ocimene are the major attractants in infested fruit volatiles. These findings and the potential for manipulating A. bishopi for detection of infested fruit in the packhouse are discussed.

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Section: Discussionmentioning

confidence: 99%

Agathis bishopi (Hymenoptera: Braconidae) as a Potential Tool for Detecting Oranges Infested with Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

et al. 2015

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“…However, NAD and its residues have been the object of studies by the European Commission and other regulatory bodies, and a risk assessment has been presented [4]. In addition, analytical methods such as luminescence [5,6] and chromatography [7,8] have been developed for its quantification in food residues and water. According to the U.S.…”

Section: Introductionmentioning

confidence: 99%

Photophysical characterization of the plant growth regulator 2-(1-naphthyl) acetamide

Silva

Wong-Wah-Chung

Sarakha

2013

Journal of Photochemistry and Photobiology A: Chemistry

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a b s t r a c tThe photophysical properties of the widely used plant growth regulator 2-(1-naphthyl) acetamide (NAD) were studied in water and representative organic solvents (ethanol, ethylene glycol, acetonitrile, chloroform, 1,4-dioxane) employing steady-state and time-resolved spectroscopy. Quantum yields and lifetimes of fluorescence, phosphorescence and triplet formation and triplet-triplet absorption spectra were obtained. From these, all radiative and radiationless rate constants have been determined, together with singlet and triplet excited state energies (4.00 and 2.69 eV, respectively). The fluorescence quantum yield and lifetime increased on going from water (˚F 0.066, F 35.0 ns) to non-hydrogen bonding solvents (˚F 0.357, F 51.0 ns in 1,4-dioxane), probably due to decreased internal conversion. Fluorescence was quenched by several anions through an electron transfer process. A limit on the reduction potential of 1 NAD* of E 0 2.1 ± 0.2 V was estimated. The attribution of the transient absorption seen in nanosecond laser flash photolysis to 3 NAD* was confirmed by energy transfer and oxygen quenching. Quenching of triplet states leads to singlet oxygen formation, with quantum yields varying from 0.097 in water to 0.396 in chloroform. However, these are lower than the triplet state quantum yields, particularly in water (˚T 0.424), indicating competing quenching pathways, probably involving electron transfer. The relevance of these results to the photoreactivity of NAD under environmental conditions is discussed.

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Effect of large volume injection of hydrophobic solvents on the retention of less hydrophobic pharmaceutical solutes in RP‐LC

Udrescu¹,

Medvedovici

David³

2008

J of Separation Science

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Injection of large volumes of samples in solvents other than mobile phase composition has been proved for some less hydrophobic compounds. Thus, the retention behavior of several compounds of pharmaceutical interest (isosorbide-2-nitrate, isosorbide-5-nitrate, tropicamide, pentoxifylline, and methyl p-hydroxybenzoate) was studied by using different hydrophobic solvents (n-hexane, n-heptane, or i-octane) as sample solvents. Two types of stationary phases were used: octyl and octadecyl modified silica (both of Zorbax Eclipse type). The experiments showed a linear dependence between capacity factor of each solute and sample injection volume, up to maximum volume values of about 680 microL for C8 stationary phase and 580 microL for C18 stationary phase, when the solutes are no longer retained in stationary phase. Injection of large volumes of these hydrophobic solvents is thus possible in RP-LC with a gradual reduction of retention and peak efficiency. Two major conditions are however necessary in order to apply such an injection approach: the solutes must have a proper solubility in hydrophobic solvents and meanwhile they have to be less hydrophobic than the sample solvent in order to avoid competition with solvent molecules in partitioning between mobile and stationary phases.

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Large-Volume Direct Injection for Determining Naphthalene Derivative Pesticides in Water Using a Restricted-Access Medium Column in RPLC-LC with Fluorescence Detection

Cited by 11 publications

References 31 publications

Agathis bishopi (Hymenoptera: Braconidae) as a Potential Tool for Detecting Oranges Infested with Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

Agathis bishopi (Hymenoptera: Braconidae) as a Potential Tool for Detecting Oranges Infested with Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

Photophysical characterization of the plant growth regulator 2-(1-naphthyl) acetamide

Effect of large volume injection of hydrophobic solvents on the retention of less hydrophobic pharmaceutical solutes in RP‐LC

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