See How Readily You Could Clamber Up The PR-171 Scale

MS data were acquired in the positive PR-171 manufacturer ion ESI mode using two alternating MS/MS scan events. Two transitions were monitored for each analyte. The selected molecular ion and optimized collision voltages of product ions used for quantification, confirmation, and ion ratio were summarized in Table 1. Applied Biosystems SCIEX Analyst software version 1.6 was employed for data acquisition and processing. Quantification was by comparison with a six-point calibration (0.0, 0.01, 0.025, 0.05, 0.1, and 0.2?mg/kg) in matrix-matched calibration. Table 1 LC-MS/MS ion parameters. 2.5. Validation Study The analytical method developed for determination of veterinary drug and pesticide residues in milk was validated according to EU Decision 2002/657/EC [16] and SANTE/11945/2015 [17]. The following parameters were evaluated in the validation procedure: selectivity, sensitivity, linearity, precision (intraday and interday reproducibility), accuracy and CC�� and CC��, LOD, and LOQ. 3. Results and Discussion 3.1. Optimization of the Extraction Procedures Ethyl acetate extraction without salt procedure was chosen to be performed in this study because of its advantages. There was no need to use salt and it could give lower detection limit in terms of volatile characteristic of ethyl acetate. YES1 Recovery values showed no difference among three different extraction procedures (acetonitrile extraction, QuEChERS extraction, and ethyl acetate extraction without salting Selleckchem AZD9291 procedure) (Figure 1). Figure 1 Recovery data for three different extraction procedures. The recovery values expressed as recovery % are all within the reference range of 70�C120%. Comparing three procedures, EtOAc without salt provided recoveries between 100% and 120% for a higher number of veterinary drugs and pesticides (26 veterinary drugs and 134 pesticides; total of 160 compounds) than QuEChERS (82 compounds) and ACN (100 compounds), as it can be observed in Figure 2. In terms of extraction recoveries, EtOAc was found to be a suitable extraction procedure for all 26 veterinary drugs and most of the pesticides analyzed in this study. Only one analyte (propham) showed R > 120 for EtOAc. Figure 2 Recovery (%) data obtained using extraction procedures; QuEChERS, ACN, and EtOAc without salt. Accuracy was evaluated in terms of relative standard deviation (RSD) by spiking blank samples with the corresponding volume of the multicompound working standard solution. RSD was evaluated at 50?��g/kg by spiking six blank samples at each level for three procedures that provided similar RSD values. These values were within 1