Plant-growth regulant.  Determination of chlorocholine chloride residues in wheat grain, straw, and green wheat foliage

Mooney, Robert P.; Pasarela, N. R.

doi:10.1021/jf60154a004

Cited by 24 publications

(11 citation statements)

References 8 publications

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“…In some cases they may be difficult to implement if the equipment is not available in the analytical laboratory. Chemical transformation of the analyte with sodium phenylsulfide [20] or potassium pentafluorothiophenolate [21] has also been exploited in order to enable a gas chromatographic detection. The latter has been considered not sufficiently specific for CMQ and this may be misleading to an analyst using it or adapting it to other procedures [22].…”

Section: Introductionmentioning

confidence: 99%

Chlormequat Selective Electrodes: Construction, Evaluation and Application at Fia Systems

Sales¹,

Lino²,

Paíga³

2003

International Journal of Environmental Analytical Chemistry

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A flow injection analysis (FIA) system having a chlormequat selective electrode is proposed. Several electrodes with poly(vinyl chloride) based membranes were constructed for this purpose. Comparative character-ization suggested the use of membrane with chlormequat tetraphenylborate and dibutylphthalate. On a single-line FIA set-up, operating with 1 x 10 -2 mol L -1 ionic strength and 6.3 pH, calibration curves presented slopes of 53.6 ± 0.4 mV decade -1 within 5.0 x 10 -6 and 1.0 x 10 -3 mol L -1, and squared correlation coeffi-cients > 0.9953. The detection limit was 2.2 x 10 -6 mol L -1 and the repeatability equal to ±0.68 mV (0.7%). A dual-channel FIA manifold was therefore constructed, enabling automatic attainment of previous ionic strength and pH conditions and thus eliminating sample preparation steps. Slopes of 45.5 ± 0.2 mV dec-ade -1 along a concentration range of 8.0 x 10 -6 to 1.0 x 10 -3 mol L -1 with a repeatability ±0.4 mV (0.69%) were obtained. Analyses of real samples were performed, and recovery gave results ranging from 96.6 to 101.1%.

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Section: Introductionmentioning

confidence: 99%

Chlormequat Selective Electrodes: Construction, Evaluation and Application at Fia Systems

Sales¹,

Lino²,

Paíga³

2003

International Journal of Environmental Analytical Chemistry

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“…The colorimetric methods like the one run by R.P. Mooney [2]. Using hexanitrodiphenylamine are not specific for the chlormequat determination and give positive reaction with the amines naturally present in plants.…”

Section: Introductionmentioning

confidence: 99%

Determination of chlormequat in pears by high-performance thin layer chromatography and high-performance liquid chromatography with conductimetric detection

2000

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The chlormequat (2-chloroethyl trimethylammonium) is a plant growth regulator, which acts mainly on the length of the internodes and leaf-stalks and on the leaves'chlorophyll content. It is used as a stabilizer of the length of the cereal stems as well as a flowering increase and organisation regulator of fruits and vegetables. In France the chlormequat is not authorized for the treatment of the pears, however a maximum residue limit of 3 ppm has been admitted (Arrêté du 5/8/92, Journal Officiel de la République Francaise and Directive 90-642 CEE). The origin of pears from various countries where this treatment is authorized and the possible confusion between national and foreign origin for the shares, have caused an emphatic request for the research of this product. Very quickly, it appeared that the methods described in the literature were not suitable to a systematic research of this pesticide. Many methods exist for the research of the quaternary amines, but a very few are workable with an ordinary material, good sensibility and on a fast procedure. For the most part the determination of this type of growth regulator needs to pass through several stages of purifications before any analysis is carried out. So G. Petrosini [1] uses cation exchange resin and alumina columns. The colorimetric methods like the one run by R.P. Mooney [2]. Using hexanitrodiphenylamine are not specific for the chlormequat determination and give positive reaction with the amines naturally present in plants.Methods using thin-layer chromatography are generally easy to use, however the proposed purification before platedeposit usually takes a long time and are costly with solvent. Stijve The high resolution liquid chromatography often used for the herbicides like the paraquat and the diquat, could be used under certain restriction for the chlormequat research [7-8-9]. However, the detection by absorption within the UV is not usable for some compounds having a weak absorption level even at short wave lengths.Liquid chromatography associated with mass spectrometry is no doubt the best adapted method for the research of this type of herbicide [10][11]. However, it is a heavy technique little adapted at present time for small size laboratories.The present work describes the way for extraction and two methods for the research and the quantification of chlormequat in the pears. The residues are extracted from plant material with sodium tetraphenylborate solution. Sodium tetraborate is a general precipitation reagent for Abstract. The purpose of this paper is to present two simplified methods which involve inexpensive equipment and which can be applied by all analyst who have to determine chlormequat residues in pears. The two methods use the extraction with methanol and purification by formation of ion-pair with sodium tetraphenylborate. A first method is a high-performance thin layer chromatography (HPTLC), the second is high-performance liquid chromatography (HPLC) with conductimetric detector. The results obtained for the same samples by ...

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“…Analytical methods used thus far for the determination of chlormequat are generally based on non‐specific detection techniques, which necessitate time‐consuming procedures for clean‐up and for separation of chlormequat from naturally occurring or co‐formulated choline derivatives 9–11. A gas chromatographic (GC) approach based on the determination of methyl chloride produced by pyrolysis has been shown to be prone to interferences and poor yield, leading to unreliable quantification 12.…”

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confidence: 99%

Rapid method for determination of chlormequat residues in tomato products by ion‐exchange liquid chromatography/electrospray tandem mass spectrometry

Careri

Elviri

Mangia

et al. 2002

Rapid Comm Mass Spectrometry

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A rapid method has been devised for the direct determination of chlormequat in tomato samples. No clean-up is required, and analysis uses ion-exchange liquid chromatography/tandem mass spectrometry interfaced with electrospray ionization (LC/ESI-MS/MS). A cation-exchange column was used with an aqueous ammonium acetate/acetonitrile mixture as the mobile phase under isocratic conditions. The method was validated in terms of detection limits (LOD), quantitation limits (LOQ), linearity, recovery, precision and accuracy. Good results in the low micro g kg(-1) level were obtained for the LOD and LOQ of chlormequat in tomato samples. Comparison of solvent and matrix-matched calibration curves demonstrated the absence of significant matrix effects and the feasibility of using external calibration. Linearity was established over two orders of magnitude by performing homoscedasticity and Mandel fitting statistical tests. The absence of both constant and proportional systematic errors was verified by evaluating the recovery function, demonstrating good method accuracy. Excellent precision in terms of intra-day repeatability was calculated (RSD% <3.4). Extraction recoveries from tomato products were calculated, by using a labelled internal standard (d(4)-chlormequat), to be in the 93 +/- 5-99 +/- 7% range. The applicability of the method to the determination of chlormequat residues in tomato products was demonstrated.

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Plant-growth regulant. Determination of chlorocholine chloride residues in wheat grain, straw, and green wheat foliage

Cited by 24 publications

References 8 publications

Chlormequat Selective Electrodes: Construction, Evaluation and Application at Fia Systems

Chlormequat Selective Electrodes: Construction, Evaluation and Application at Fia Systems

Determination of chlormequat in pears by high-performance thin layer chromatography and high-performance liquid chromatography with conductimetric detection

Rapid method for determination of chlormequat residues in tomato products by ion‐exchange liquid chromatography/electrospray tandem mass spectrometry

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