• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.157-163
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• 2012

BACKGROUND: For the safety of imported agricultural products, the study was conducted to develop the analytical method of unregistered pesticides in domestic. The analytical method of 6 pesticides, chlorthal-dimethyl, clomeprop, diflufenican, hexachlorobenzene, picolinafen, and propyzamide, for a fast multi-residue analysis were established for two different type crops, orange and brown rice by GC-ECD and confirmed by mass spectrometry. METHODS AND RESULTS: The analytical method was evaluated to limit of quantification, linearity and recoveries. The crop samples were extracted with acetonitrile and performed cleanup by liquid-liquid partition and Florisil SPE to remove co-extracted matrix. The extracted samples were analyzed by GC-ECD with good sensitivity and selectivity of the method. The limits of quantification (LOQ) range of the method with S/N ratio of 10 was 0.02~0.05 mg/kg for orange and brown rice. The linearity for targeted pesticides were $R^2$ >0.999 at the levels ranged from 0.05 to 10.0 mg/kg. The average recoveries ranged from 74.4% to 110.3% with the percentage of coefficient variation in the range 0.2~8.8% at two different spiking levels (0.02 mg/kg and 0.2 mg/kg, 0.05 mg/kg and 0.5 mg/kg) in brown rice. And the average recoveries ranged from 77.8% to 118.4% with the percentage of coefficient variation in the range 0.2~6.6% at two different spiking levels (0.02 mg/kg and 0.2 mg/kg, 0.05 mg/kg and 0.5 mg/kg) in orange. Final determination was by gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) to identify the targeted pesticides. CONCLUSION: As a result, this developed analytical method can be used as an official method for imported agricultural products.

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.153-164
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• 1999

The solubilization of BTEX was evaluated in aqueous surfactant solutions with and without several additives. Anionic surfactant(Sodium Dodecyl Sulfate, SDS) and nonionic surfactants (NEODOL(equation omitted)25-3 and $SOFTANOL\circledR-90$ were used as test surfactants. The effects of surfactant HLB(Hydrophile-Lipophile Balance) Number and hydrocarbon molar volume and polarity of BTEX on the MSR(Molar Solubilization Ratio), micelle-water partition coefficient of BTEX, and CMC(C,itical Micelle Concentration) were investigated. Optimizing treatment conditions applicable to enhanced solubilization was also studied by manupulating salinity or electrolyte control with additives of ethyl alcohol, hydrotrope, and electrolyte solution. The most effective surfactant for solubilization was found $SOFTANOL\circledR-90$, since HLB number of 13.6 is similar to those values of BTEX ranging between 11.4 and 12.2, which was also proved experimentally. Ethyl alchohol of 3% was the most effective additives in reducing CMC and improving solubilization among the conditions using SDS, NEODOL(equation omitted)25-3, and $SOFTANOL\circledR-90$ with three additives. The partitioning of BTEX between surfactant micelles and aqueous solutions was characterized by a mole fraction micelle-phase/aqueous phase partion coefficient, $K_m$. Values of log $K_m$. for BTEX compounds in surfactant solutions of this study range from 2.95 to 3.76(100mM SDS) and 2.95 to 3.49(117mM $SOFTANOL\circledR-90$. Log $K_m$ appears to be a linear function of log $K_{ow}$ for SDS and $SOFTANOL\circledR-90$. A knowledge of partitioning of BTEX in aqueous surfactant system can be a prerequisite for the understanding of the behavior of hydrophobic organic compounds in soil-water systems in which surfactants play a role in remediation of contaminated soil and facilitated transport.