Quantitation of azadirachtins in insecticidal formulations by high-performance liquid chromatography

Hull, Clifford J.; Dutton, Walter; Switzer, Barbara S.

doi:10.1016/0021-9673(93)83167-q

Cited by 24 publications

(17 citation statements)

References 12 publications

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“…To avoid clogging, column washing is required. Hull et al [26] suggested column cleaning using tetrahydrofuran (THF) for 5 min at the end of each run. The column needs to be re-equilibrated with the mobile phase.…”

Section: Resultsmentioning

confidence: 99%

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Determination of azadirachtin and fatty acid methyl esters of Azadirachta indica seeds by HPLC and GLC

Kaushik¹

2002

Anal Bioanal Chem

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A simple and economical method has been developed to estimate the azadirachtin content and fatty acid composition of neem kernels. Neem kernels are crushed and soaked overnight in ethanol. The extract obtained is analysed by HPLC after filtering through a 0.22 micro m membrane. The peaks are separated using acetonitrile-water (40:60) 1 mL min(-1) as the mobile phase on an RP-18 column and monitored at 214 nm. For the determination of fatty acid composition, the fatty acids are directly transmethylated in the kernel powder by heating with methanol-acetyl chloride-benzene (20:1:4, v/v) for 1 h in a water bath. The fatty acid methyl esters (FAMEs) obtained are extracted in hexane and analysed using GLC. The separation of the FAMEs is achieved using an RH-Wax column using temperature programming, 170-200 degrees C at 2 degrees min(-1). The peaks are detected using an FID. Both the methods do not require any clean up or defatting of seeds. This results in faster, easier and more economical sample preparation.

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Section: Resultsmentioning

confidence: 99%

“…Hull et al [26] described the use of HPLC for quantification of azadirachtin in new formulations using C 18 solid-phase extraction (SPE) cartridges for clean-up of the sample. However, Azam et al [27] employed column chromatography for the clean-up of samples of emulsifiable and solution concentrate of neem.…”

Section: Introductionmentioning

confidence: 99%

Determination of azadirachtin and fatty acid methyl esters of Azadirachta indica seeds by HPLC and GLC

Kaushik¹

2002

Anal Bioanal Chem

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“…Several publications have dealt with different techniques for the separation and identification of products contained in neem extracts [5,6,7,8,9,10,11,12,13,14,15,16]. Separation in these studies involved reversed-phase liquid chromatography (RP-HPLC) [6,8,9,11,12,13,14,15,16], using octadecylsilane (C 18 ) columns and detection by ultraviolet absorption.…”

Section: Introductionmentioning

confidence: 99%

“…Separation in these studies involved reversed-phase liquid chromatography (RP-HPLC) [6,8,9,11,12,13,14,15,16], using octadecylsilane (C 18 ) columns and detection by ultraviolet absorption. These coupled methods are effective for separation and detection of compounds present in the oil extracted from neem but are insufficient to identify all the compounds in insecticide formulations, because of their chemical complexity.…”

Section: Introductionmentioning

confidence: 99%

Analysis of neem oils by LC?MS and degradation kinetics of azadirachtin-A in a controlled environment

Barrek

Paisse

Grenier‐Loustalot

2004

Analytical and Bioanalytical Chemistry

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Since it was first isolated, the oil extracted from seeds of neem (Azadirachtin indica A juss) has been extensively studied in terms of its efficacy as an insecticide. Several industrial formulations are produced as emulsifiable solutions containing a stated titer of the active ingredient azadirachtin-A (AZ-A). The work reported here is the characterization of a formulation of this insecticide marketed under the name of Neem-azal T/S and kinetic studies of the major active ingredient of this formulation. We initially performed liquid-liquid extraction to isolate the neem oil from other ingredients in the commercial mixture. This was followed by a purification using flash chromatography and semi-preparative chromatography, leading to (13)C NMR identification of structures such as azadirachtin-A, azadirachtin-B, and azadirachtin-H. The neem extract was also characterized by HPLC-MS using two ionization sources, APCI (atmospheric pressure chemical ionization) and ESI (electrospray ionization) in positive and negative ion modes of detection. This led to the identification of other compounds present in the extract-azadirachtin-D, azadirachtin-I, deacetylnimbin, deacetylsalannin, nimbin, and salannin. The comparative study of data gathered by use of the two ionization sources is discussed and shows that the ESI source enables the largest number of structures to be identified. In a second part, kinetic changes in the main product (AZ-A) were studied under precise conditions of pH (2, 4, 6, and 8), temperature (40 to 70 degrees C), and light (UV, dark room and in daylight). This enabled us to determine the degradation kinetics of the product (AZ-A) over time. The activation energy of the molecule (75+/-9 kJ mol(-1)) was determined by examining thermal stability in the range 40 to 70 degrees C. The degradation products of this compound were identified by use of HPLC-MS and HPLC-MS-MS. The results enabled proposal of a chemical degradation reaction route for AZ-A under different conditions of pH and temperature. The data show that at room temperature and pH between 4 and 5 the product degrades into two preferential forms that are hydrolyzed to a single product over time and as a function of pH change.

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“…Prior to use, the total content of azadirachtin (A and B) ( Fig. 1) in MO was determined to be 2.5 g/1 by HPLC (Hull et al 1993).…”

Section: Chemicalsmentioning

confidence: 99%

Persistence of azadirachtin A and B in soil: Effects of temperature and microbial activity

Stark

Walter

1995

J. of Env. Sc. & Hlth., Part B

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The persistence of two insecticidally active compounds from the neem tree, azadirachtin A and B, was determined at two different temperatures (15 and 25°C) in the laboratory after application of the commercial neem insecticide, Margosan-O, to a sandy loam soil. The influence of microbial activity on degradation was also examined by comparing autoclaved and non-autoclaved soils also at 15 and 25°C. Temperature influenced degradation rates. The DT 50 (time required for 50% disappearance of the initial concentration) for azadirachtin A was 43.9 and 19.8 d for non-autoclaved soil kept at 15 and 25°C, respectively. The DT 50 for 685 686 STARK AND WALTER azadirachtin B was 59.2 and 20.8 d for non-autoclaved soil kept at 15 and 25°C, respectively. Microbial activity was also responsible for faster degradation because DT 50 'S for autoclaved soil were much longer than for non-autoclaved soils. DT 50 ' S for azadirachtin A in autoclaved soil were 91.2 (15°C) and 31.5 d (25°C). DT50'S for azadirachtin B in autoclaved soil were 115.5 (15°C) and 42.3 d (25°C). Two degradation products of azadirachtin were detected, but were not identified. Higher levels of the two degradation products were detected in nonautoclaved soil.

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Quantitation of azadirachtins in insecticidal formulations by high-performance liquid chromatography

Cited by 24 publications

References 12 publications

Determination of azadirachtin and fatty acid methyl esters of Azadirachta indica seeds by HPLC and GLC

Determination of azadirachtin and fatty acid methyl esters of Azadirachta indica seeds by HPLC and GLC

Analysis of neem oils by LC?MS and degradation kinetics of azadirachtin-A in a controlled environment

Persistence of azadirachtin A and B in soil: Effects of temperature and microbial activity

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