Determination of residues of Maleic Hydrazide in garlic bulbs by HPLC

MAMANI MORENO, C. M.; STADLER, T.; DA SILVA, A. A.; ALMEIDA BARBOSA, L. C.; LOPES RIBEIRO DE QUEIROZ, M. E.

Montevideo

Workshop; 3rd Latin American Pesticide Residue Workshop Food and Environment; 2011

LAPRW

In recent years, the release of information about the preventive and curative properties of garlic on different diseases and their benefits to human health has led to an increase in the consumption of garlic. To meet the requirements of international markets and reach competitiveness and profitability, farmers seek to extend the offer period of fresh garlic, increasing post-harvest life. As a result, the use of maleic hydrazide (1,2– dihydro-3,6-pyridazinedione) [MH], a plant growth regulator, has been widespread in various garlic growing regions of the world. The present work was undertaken to develop and validate a new analytical procedure based on extraction by liquid nitrogen with low temperature clean up and demonstrate its applicability for the extraction of MH from garlic samples and subsequent determination by HPLC / UV, reverse phase. The influence of some factors on the performance of the analytical methodology were studied and optimized. The approach is an efficient extraction clean up and determination alternative for MH residue-quantification due to its specificity and sensitivity. The fact of using liquid nitrogen ensures no oxidation reactions of MH in homogenized plant tissue, main factor limiting performance. Moreover, the method provides good linearity (r2: 0,999), good intermediate precision (CV: 8,39%), and extracts were not affected by matrix effect. Under optimized conditions, the LOD (0,33 mg Kg-1) was well below the MRL set internationally for garlic (15 mg Kg-1), with excellent rates of recovery (over 95 %), good repeatability and acceptable accuracy (CV averaged 5,74%), since garlic is a complex matrix. The analytical performance of the methodology presented was compared with other techniques already reported, with highly satisfactory results, as lower LOD and higher recoveries rates. In addition, the extraction process is simple, no expensive, requires lower volumes of organic solvent, easily executable. The proposed methodology removes the need of extensive typical laboratory extraction procedures, reducing the amount of time needed for pesticide analysis and increasing sample throughput. Adopting this method gives food safety laboratories the potential to increase cost savings by a suitable technique in routine testing to determine MH residues in garlic.