Two-phase partition chromatography using soybean oil eliminates pesticide residues in aqueous ginseng extract.

This study was carried out to develop a cost-, labor- and efficiency-effective elimination method of pesticide residues in ginseng extract. A two-phase partition method between soybean oil and distilled water or aqueous ginseng extract was employed for the elimination of pesticide residues. Content of the pesticides was determined by gas chromatography with electron capture or nitrogen phosphorus detector. A total of 15 pesticides representing four categories (organochlorine, organophosphorus, carbamate, pyrethroid) were spiked (ca. 2 ppm) to 2 ml soybean oil in a test tube and the oil was mixed with 6 ml distilled water or 10% aqueous ginseng extract. The test tubes were then vortexed (2 min) and centrifuged at 3000 rpm for 15 min to separate the oil and aqueous layers. Each layer was harvested and subjected to quantitative analysis of pesticides. The average distribution ratio of the pesticides to the oil layer was 94.4 +/- 6.7% in the mixture of the oil and distilled water, and 105.5 +/- 6.6% in the mixture of the oil and ginseng extract. No significant qualitative and quantitative change of ginsenosides, the active ingredients of Panax ginseng, was observed in the ginseng extract before and after the oil treatment. These results suggest that two-phase partition chromatography between soybean oil and the aqueous phase is a cost-, labor- and efficiency-effective reliable method for the elimination of pesticide residues in ginseng extract.

Contribution of individual polyphenolics to total antioxidant capacity of plums.

To study the effect of polyphenolics on antioxidant capacities of plums, the amounts of total phenolics, total flavonoids and individual phenolic compounds, and vitamin C equivalent antioxidant capacity (VCEAC) of eleven plum cultivars was determined. There was a good linear relationship between the amount of total phenolics and total antioxidant capacity (r2 = 0.9887). The amount of total flavonoids and total antioxidant capacity also showed a good correlation (r2 = 0.9653). Although the summation of individual antioxidant capacity was lower than the total antioxidant capacity of plum samples, there was a positive correlation (r2 = 0.9299) of total antioxidant capacity of plum samples with the sum of the VCEACs calculated from individual phenolics. Chlorogenic acids and glycosides of cyanidin, peonidin, and quercetin were major phenolics among eleven plum cultivars. The antioxidant capacity of chlorogenic acids and anthocyanins showed higher correlation (r2) of 0.7751 and 0.6616 to total VCEAC, respectively, than that of quercetin glycosides (r2 = 0.0279). Chlorogenic acids were a major source of antioxidant activity in plums, and the consumption of one serving (100 g) of plums can provide antioxidants equivalent to 144.4-889.6 mg of vitamin C.

Multiresidue method for the determination of pesticides in Korean domestic crops by gas chromatography/mass selective detection.

The multiresidue method used in this study allows the determination of 101 pesticides, including organophosphorus, organochlorine, and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector. Analysis was performed in the selected-ion monitoring mode, and the identities of the positive analytes were confirmed by retention time and the ratios of selected ions. The selected ion mode demonstrated an acceptable selectivity for most of the pesticides determined in 3 kinds of samples (Chrysanthemum coronarium; Perilla japonica, leaf; and Lactuca savita, which are very popular vegetables eaten raw in Korea), and very minor interferences were observed in the elution area of the pesticide analytes. Samples were spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% of the pesticides were between 70 and 110%; however, the recoveries of acephate and folpet were very poor, i.e., < 50%. The limits of detection (LODs) for most pesticides were between 0.02 and 0.3 mg/kg, and the LODs for about half of the pesticeds studied were < 0.05 mg/kg.

Estimation of risks of pesticide exposure, by food intake, to Koreans.

The aim of this study was to evaluate theoretical maximum daily intake (TMDI) and estimated daily intake (EDI) for Korean by using maximum residue levels (MRLs), food intake, residue data and correction factors, and compare with acceptable daily intake (ADI) in order to estimate the health risk based on the pesticide exposure. Then, the oncogenic risks of the pesticides were assessed from TMDI and estimated daily intake with treatment (adjusted EDI). The percent ratio of TMDI to ADI for 262 pesticides was mostly below 80%, but 42 pesticides (16.0%) exceeded the ADI. EDI without treatment (non-adjusted EDI) and estimated daily intake with treatment (adjusted EDI) were summed up to about 6.41 ml/day/capita and 2.94 ml/day/capita, respectively. The percentage of ADI was TMDI (101.04%) > non-adjusted EDI (0.08%) > adjusted EDI (0.01%), and the exposure level of Korean population to whole pesticides was below the level to produce health risk. The dietary oncogenic risk for Koreans was estimated to be 7.3x10(-4) on the basis of TMDI, 1.8x10(-7) on the basis of adjusted EDI, and although the level from TMDI exceeded the risk level (1x10(-6)) of the Environment Protection Agency (EPA), the level from adjusted EDI, real exposure level, was below it.