Determination of Dithiocarbamate Fungicide Residues in Food by a Spectrophotometric Method Using a Vertical Disulfide Reaction System

Abstract

Dithiocarbamates are a class of fungicides extensively used in many crops worldwide. The current residue definition of dithiocarbamates in food for compliance with maximum residue limits, at national and international levels, is total residues arising from the use of any or each dithiocarbamate fungicide, determined as CS(2). The analytical method most frequently used to analyze dithiocarbamate residues in food for monitoring purposes was proposed more than 30 years ago. In this method, total dithiocarbamates are decomposed to CS(2), which is purified and reacted with a cupric reagent. The yellow complex formed is quantified by spectrophotometry. In this paper, a new reaction system for the purification and complexation of CS(2) is proposed. The new system is less fragile than the traditional design, is easier to assemble, and allows for a higher sample throughput, in addition to being of low cost. Recovery of added mancozeb, thiram, or ziram (0.15-8.0 mg/kg) in rice, beans, apple, banana, orange, papaya, tomato, cucumber, and potato ranged from 82 to 120%, with relative standard deviations from 0 to 10% (n = 3 or 5). Analysis of apple, tomato, and papaya samples with field-incurred dithiocarbamate residues showed comparable results using both the traditional and the new reaction systems.

The Impact of Washing and Peeling of Cucumbers and Tomatoes in Reduction of Daily Intake of Dithiocarbamates

“…The outcomes demonstrated that even in peeled vegetables the DTCs remnant is detected. The dithiocarbamates remnants in Brazilian food have been stated by Caldas et al, their outcomes mentioned that detectable DTCs remnants were found in the pulp of banana, papaya (including the seeds) and orange (50-62% of the analyzed samples) [20]. The outcomes of our study showed that 38.2 and 26 µg/Kg DTCs remnants were caught in the pulp of cucumber and tomatoes respectively.…”

Adsorption Thermodynamics and Kinetics of Mancozeb onto Poly-o-toluidine Th(IV) Phosphate — a Nano-composite Cation-exchanger — and its Application as a Mancozeb-sensitive Membrane Electrode

“…A system based on the design of Caldas et al (2001) was used for the determination of Mancozeb. This consisted of a two-necked round-bottom flask connected to a condenser, which was connected in turn to two traps in series.…”

“…These flasks were then shaken at 25 o C, 35 o C or 45 o C for different time intervals until equilibrium was attained. The resulting supernatant liquid was analyzed employing the traditional CS 2 reaction system (Caldas et al 2001). The percentage adsorbed (% Ads) was calculated from the relationship:…”

Pesticide Residues Evaluation in Pulp, Juice and Nectar of Fruits

“…Dithiocarbamates fungicides were analyzed employing the spectrophotometer to determine the CS 2 concentration (Caldas et al, 2001). …”