The octanol–air partition coefficients (KOA) for PBB15, PBB26, PBB31, PBB49, PBB103 and PBB153 were determined as a function of temperature using a gas chromatographic retention time technique with 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (p,p′-DDT) as a reference substance. The internal energies of phase change from octanol to air (ΔOAU) were calculated for the six compounds and were in the range from 74 to 116 kJ mol−1. Simple regression equations of log KOA versus relative retention times (RRTs) on gas chromatography (GC), and log KOA versus molecular connectivity indexes (MCI) were obtained, for which the correlation coefficients (r2) were greater than 0.985 at 283.15 K and 298.15 K. Thus the KOA values of the remaining PBBs can be predicted by using their RRTs and MCI according to these relationships. 相似文献
A new analytical method using accelerated solvent extraction was developed for the determination of 10 particle-associated polar and semipolar pesticides. In addition, six deuterated analogues of the target compounds were evaluated as internal standards. The method yielded acceptable accuracy (73–103% recovery) and precision (<25% relative standard deviation) for eight compounds. Using size exclusion chromatography (SEC) as cleanup step resulted in higher recoveries compared to solid phase extraction (SPE) cleanup.
Deuterated standards with 10 or more deuterium atoms performed well as internal standards concerning similar recovery and correlation with the target analytes.
The method was employed to extract particle-associated pesticides from 16 streams located in an area with intense agriculture in France. Acetochlor, pirimicarb, tebuconazole, fenpropidin, -endosulfan and chlorfenvinphos were detected at concentrations up to 1 mg kg−1 dry weight. A comparison with aquatic toxicity data indicated potential risk to the benthic fauna exposed to these concentrations of pirimicarb, -endosulfan and chlorfenvinphos.
We suggest that the method presented here be used for the extraction and quantitation of particle-associated polar pesticides. 相似文献
Carbamate compounds are an important group of cholinesterase inhibitors. There is a need for creating awareness regarding the risks of the inadequate carbamate use in the residential areas due to potential adverse human effects. Carbaryl is a commonly used pesticide worldwide. A simple, fast, and high-throughput method was developed employing liquid chromatography with fluorescence detector to determine carbaryl residues in rat feces. The extraction was performed by using a rapid, easy, cheap, effective, reliable, and safe (QuEChERS) method, using acetonitrile as the extracting solvent. The parameters for the performance of the extraction method were optimized, such as ratio of mass of sample per volume of extraction solvent, QuEChERS content, and cleanup columns. Linear response was obtained for all calibration curves (solvent and matrix-matched) over the established concentration range (5–500 μg/L) with a correlation coefficients higher than 0.999. The achieved recovery was 97.9% with relative standard deviation values of 1.1% (n = 4) at 167 μg/kg fortified concentration level and the limits of detection and quantification were 27.7 and 92.3 µg/kg, respectively. 相似文献
The efficiency of water rinsing for removing fenthion from non-combustible used pesticide containers was investigated. Four hundred empty containers from four olive oil producing areas in Greece were studied. Following triple rinsing cleaning procedures, the amount of fenthion retained in the container ranged from 0.01% to 0.1% w/w of its initial concentration. Extraction was accomplished with acetone, and the extracts were analyzed with a capillary gas chromatographic system coupled with flame ionization detector. The results obtained showed that triple rinsing is an effective procedure for removing fenthion from used pesticide containers, since the remaining pesticide concentration was below the legislated threshold value. Consequently, the containers can be handled as non-hazardous solid wastes. 相似文献