RESUMO
An enhance matrix removal ( EMR) QuEChERS method for simultaneous determination of 22 triazine herbicide residuals such as atrazine, propazine, terbumeton, and desmetryn in corn was established and validated. The corn samples were initially extracted with acetonitrile ( MeCN ) in high-speed homogenization, and the targeted pesticides were prepared using EMR-Lipid (Enhanced matrix removal-lipid) method to clean-up and EMR-Polish to salt out, separated on a Kinetex XB-C18 with acetonitrile and 0. 1%formic acid aqueous as eluant, and then detected by UFLC-MS / MS under positive ( ESI+ ) electrospray ionization and MRM models. The average recoveries of 22 herbicides were in the range of 72% -105% at the spiked level of 5, 10 and 20 μg / kg. The relative standard deviations were less than 15% . In the method validation, correlation coefficients were higher than 0. 993 with the linear range from 1. 0 μg / L to 50 μg / L. The qualitative analysis and quantitative analysis were investigated by UFLC-MS / MS and matrix-matched calibration curves. The results showed that EMR QuEChERS combined with UFLC-MS / MS purification method was rapid, accurate and sensitive for the determination of 22 triazine herbicides residues in corn.
RESUMO
Objective To investigate pulmonary function of tidal respiration in late premature infants with non-mechanical ventilation treatment at corrected gestational age of full term. Methods A total of 26 late premature infants with non-mechanical ventilation treatment at corrected gestational age of full term were collected from Qingdao Women and Children′s Hospital between April and December 2013,and saved as the late premature infant group. Also, a total of 31 full term infants with hyperbilirubinemia or neonatal ABO hemolytic disease were recruited and treated as the full term group. Then the parameters of pulmonary func-tion of tidal respiration were compared between the two groups. The late premature infant group was equally allocated into extrauterine growth retardation and non-extrauterine growth retardation groups according to the increase in weight and the ratio of time to peak tidal expiratory flow and total expiratory time(TPEF/TE) and the ratio of expiratory volume at peak tidal expiratory flow and total expiratory volume( VPEF/VE) were respectively compared in these two groups. Another correlation analysis between body weight and TPEF/TE was carried out in the non-extrauterine growth retardation group. Results (1)Gestational age difference had no significant significance between late premature infant group and full term group ( P <0. 05 ) . The body weight[(2. 39 ± 0. 44)kg vs. (3. 21 ± 0. 43) kg] and height[(46. 51 ± 3. 22) cm vs. (50. 16 ± 2. 14) cm] in late premature infant group were still lag behind that in full term group and the difference had significant significance(P<0. 05,respectively). (2)The comparison of parameters of pulmonary function of tidal respi-ration:the TPEF/TE [ ( 41. 74 ± 10. 94 )% vs. ( 48. 17 ± 11. 79 )%] , VPEF/VE [ ( 42. 66 ± 9. 66 )% vs. (48. 31 ± 9. 94)%],VPEF[(8. 02 ± 2. 85) ml vs. (10. 23 ± 3. 56) ml] and minute ventilation[(0. 76 ± 0. 23) L/min vs. (1. 00 ± 0. 44) L/min] in late premature infant group were significantly lower than those in full term group(P<0. 05,respectively). (3)The TPEF/TE and VPEF/VE all had significant significance in both late premature infant group and full term group(late premature infant group:r=0. 958,P=0. 000; full term group:r=0. 950,P=0. 000). (4)The TPEF/TE and VPEF/VE in non-extrauterine growth retardation group were closer to those in full term group. The TPEF/TE and VPEF/VE in extrauterine growth retardation group were lower than those in non-extrauterine growth retardation group(t= -2. 775,-2. 109,P=0. 011, 0. 047). Conclusion Airway(especially small airway) resistance of late preterm infant group is higher than that of term infants. Extrauterine growth retardation influences the airway(especially small airway) resist-ance.