Spiked blank samples were used as the matrix to carry out the optimization study and analytical recovery study. Approximately 50 g of sample was placed in a beaker with a broad base and covered with 50 mL of n hexane spiked with the targets to obtain a final concen tration in the matrix of 0. 05 mg/kg in each analyte. The samples were exposed to ultrasonic bath for 20 min and kept in room temperature for 12 h to equilibrate the analytes in the black, and stored at 41C before extraction, in order to simulate the normal interaction between the samples and the herbicide compounds. For demonstrating the suitability of the instructed method for the extraction of the target compounds from real samples, other spiked levels of samples were similarly subjected to the process. 2.

2 Instrumentation An automated ASE 300 system with 34 mL stainless steel extraction vessels was from Dionex. A high speed homogenizer machine FSH P was from Huanyu Factory. The GC ECD equipment consisted of a Finnigan Trace GC Ultra chromatograph equipped with a 63Ni electron capture detector, an auto sampler, a split splitless injector mTOR Inhibitors and a DB 5 fused silica capillary column of dimensions 30 m _ 0. 25 mm id _ 0. 25 mm film thickness. 2. 5 Extraction procedure For ASE, 2. 00 g of each sample was mixed in a mortar with 4. 00 g of Na 2SO 4, and the mixture was added directly to the extraction cell containing cellulose extraction filters to prevent frit blockage of fine powder breakthrough into the collection bottle. The extraction was performed under the optimized conditions extraction solvent: acetone, tempera ture: 501C, pressure: 10.

34 MPa, Entinostat static time: 5 min, heat up time: 5 min, ush volume: 60%, purge: N 2, 60 s, number of cycles: 2. Shake extraction was performed using 2. 00 g portion of sample in an Erlenmeyer ask in 50 mL acetone solution. The samples were first manually agitated and immersed in 50 mL acetone solution for 2 h. shaken in a Ronghua HY 2A mechanical shaker for 30 min three times. After each extraction period, extracts were collected by pouring the extractant through a funnel plugged with a small piece of cotton wool overlaid by a portion of Na 2SO 4, which had been previously washed with the same solvent. After extraction, the samples were evaporated to a drop in a rotary evaporator and dried by means of nitrogen stream. Finally, the extraction was dissolved in 1.

00 mL of n hexane for the clean up step. 2. 6 Cleanup procedure The GCB/PSA commercial SPE tubes were conditioned with 10 mL of acetonitrile/toluene. The sample extracts were loaded onto the cartridge and subsequently eluted with 15 mL of acetonitrile/toluene. Finally, elutes were evaporated to a drop in a rotary Ion Channel evaporator and dried by a gentle nitrogen stream. Once dissolution in 1. 00 mL n hexane, the solution was filtered through a syringe filter PTFE of 0. 45 mm for the determination by GC ECD. 3 Results and discussion 3. 1 Study of ASE condition Extraction can vary in degree of selectivity, speed and convenience and largely depends not only on the approach and conditions used but also on the geometric configura tions of the extraction phase.

Proper designing of the extraction condition facilitates convenient on site imple mentation, integration with sampling and separation/ quantification, Protease quantification, automation or both. In this work, four factors were studied in order to achieve the best efficient extractions for acetanilide herbicides from cereal productions, they were oven temperature, static extraction time, static cycles and extraction solvent. Temperature is the most important factor used in ASE. The extraction temperature has in uence on extraction kinetics and solvent viscosities and therefore also on extraction efficiencies and overall recoveries. Three oven temperatures were assayed: 50, 80 and 1101C to study the temperature on the extraction efficiencies. Figure 1A shows the effect of temperature on the extraction efficiency of ASE for eight acetanilide herbicides.

The recoveries of the analytes acquired from 50, 80 and 1101C were 84 120, 86 138 and 75 125%, respectively. At 80 and 1101C recov eries acquired were slightly lower than at 501C, especially for the most easily degradable compounds, FDA such as aceto chlor and alachlor. Furthermore, the high temperature may result in more co extraction and dirty chromatograms. Therefore, 501C has to be chosen with care to obtain both high recoveries of acetanilide herbicides and matrix compounds free extracts. Aged sample matrices can retain analytes within pores or other structures and interfere with extraction efficiency. By increasing the static time at elevated temperatures, the compounds can diffuse into the extraction solvent. The effect of static time should always be explored in conjunc tion with static cycles, in order to produce a complete extraction in the most efficient way possible. However, more static time or static cycles may result in increased extraction time and co extraction. Hence, it is very impor tant to find the reasonable condition of ASE.