Authors:B. Šimundić, G. Krešić, A. Živkovićb and B. Medugorac
several pesticides from fruit and vegetables: A simple multiresidue analysis method. J. AOAC int. , 75 , 53-61.
Column extraction of residues of several pesticides from fruit and vegetables: A simple multiresidue analysis method
An improved analytical method for determining the fungicide dimethomorph in vegetables is described. The method involved single extraction with dichloromethane followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) determination. The average recovery rates from vegetable samples spiked with dimethomorph at 10 and 100 μg kg−1 (n = 5) ranged between 81 and 96% and with associated relative standard deviations ≤9%. The limits of detection (LOD) and limits of quantification (LOQ) were below 10 μg kg−1 for the three studied matrices, i.e., tomato, cucumber, and onion. Successful application of the method to the analysis of samples with incurred dimethomorph residues has been demonstrated.
This work describes the comparison of five sample extraction methods for the determination of pesticide residues in grapes and vegetables by using gas chromatography—time-of-flight mass spectrometry (GC—TOF-MS). These methods were based on original methods QuEChERS, mini-Luke, ethyl acetate, and DIN EN 15637, and some of these were slightly modified to increase the number of identified and quantified pesticides, to improve their quantification limits, and to be fast and less expensive in terms of material cost. The acceptable performance parameters combined with the properties of easy and quick handling and cost-effectiveness have made mini-Luke modified extraction method as the most favorable in the pesticide residues analysis from grapes and tomatoes by GC—TOF-MS. The efficiency of the chosen extraction method was also verified for lettuce; for this matrix, a cleanup step with graphitized black carbon (GBC) was added. Analysis of extracts was carried out by GC—TOF-MS within 29.2 min run time. The GC method was validated for grapes and tomatoes in terms of linearity, accuracy, limit of detection (LOD), and limit of quantification (LOQ). Good linearity with correlation coefficients (r2) higher than 0.98 was obtained. For most analytes from both matrices, recoveries were in the range of 71–120% and LOQ values in the range of 0.01–0.05 mg kg−1. The GC—TOF-MS and modified mini-Luke extraction methods were successfully tested on real vegetable and fruit samples belonging to the same commodities group as those from validated methods according to European Guide DG SANCO 12571/2013 (tomatoes, pepper, cucumber, potatoes, carrots, eggplants, onion, lettuce and grapes) and in proficiency EU tests.
Thrips (Thysanoptera) and their predators were investigated from 2005–2007 on a wide range of vegetables grown mostly in the winter period in Çukurova region of Turkey. A total of 2989 adult thrips and 406 thrips larvae were extracted from the vegetables. The adults belonged to 14 thrips species of which
spp. were the most dominant species. The dominance of the commonly found pests
was the predominant thrips infesting broad bean, lettuce and parsley, while
was more abundant on leek, onion and pea. The most thrips were collected from flowers or heads of vegetables in early spring. Numbers of predatory insects dwelling on the sampled vegetables were lower in comparison to total numbers of thrips obtained in the years 2006 and 2007. Of the predators, the hemipteran generalists
were the most prevalent and high numbers of them were recorded often on flowers of broad bean in winter. Further investigations should be planned to understand clearly the predatory habit of
The present paper evaluates the results of field experiments conducted during two consecutive growth seasons (2008–2009) to assess the environmental impact of cement dust pollution on foliar physiology (pigments), growth performance and yield of three commonly cultivated vegetable crops, tomato (Lycopersicon esculentum), radish (Raphanus sativus) and knol-khol (Brassica oleracea var. gongyloides) in Kashmir Himalayan valley, India. Two experimental sites (S1, S2) were selected in the vicinity of the cement factory at Khrew, Pulwama (Kashmir) at a distance of 0.5 km (S1) and 2 km (S2) and compared with a dust free control site (S3) located at about 6 km from the factory in a crosswind direction. The data revealed that cement dust had an adverse effect on morphological and biochemical characteristics of the crops. Differential level of crop sensitivity to cement dust was markedly evident. Knol-khol (Brassica oleracea var. gongyloides) reflected a higher degree of tolerance to particulate emissions as compared to tomato (Lycopersicon esculentum) and radish (Raphanus sativus). Photosynthetic pigment analysis showed adverse impact on chlorophyll-a, while chlorophyll-b marginally decreased in the leaves of tomato plants at S1; the effect being non-significant for the other test crops. Carotenoids also exhibited a remarkable reduction due to cement dust impact. The yield of tomato recorded severe losses (12.28–23.95%) as compared to radish (7.46–21.4%), while the effect was non-significant in knol-khol. Other growth and yield related attributes also followed a similar trend; tomato and radish showing remarkable effects in response to cement dust and knol-khol showed the least effect. The soil characteristics indicated significant reduction in available P. Except available N, other variables (pH, conductivity, available K, exchangeable Ca and Mg) recorded higher values in the polluted soils as compared to control. The need for installation of appropriate devices in cement manufacturing factories to combat the emission of dust in ambient environment together with environmental monitoring of agro-ecosystems is stressed.
characteristics for the quality assessment of tomatoes.
Fruit, Nut, and Vegetable Production Engineering
Dewulf, W., P. Jancsók, B. Nicolai, G. De Roeck, D. Briassoulis (1999): Determining the Firmness of a