A multiresidue method has been developed for the confirmation and quantification of 19 quinolones (enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin, flumequine, oxolinic acid, difloxacin, sarafloxacin, sparfloxacin, danofloxacin, fleroxacin, marbofloxacin, enoxacin, orbifloxacin, pefloxacin, nalidixic acid, pipemidic acid, lomefloxacin and cinoacin) in pig and fish by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with acetonitrile, analytes separated by LC on a C18 column using 0.1% formic acid-methanol with a linear gradient elution programme, and detected by MS/MS. The linear range was 0.3-50 microg kg(-1) with correlation coefficients (r) more than 0.9956. The limits of detection were 0.1 microg kg(-1). Mean recoveries for each analyte in pig muscle and fish ranged from 75.3% to 96.3% and from 79.7% to 94.2% with relative standard deviations below 10%. The method is fast, safe, sensitive and precise, and can be used simultaneously to analyse residual quinolones.

In this paper, the effects of Z-pin diameter and Z-pin length on the tensile properties of carbon fiber reinforced laminates were studied. A new Z-pin insertion technique which causes less microdamage damage than the original method was developed. Experimental testing reveals that the in-plane tensile strength of Z-pin specimens is 96.98%-105.32% of the control group. The best performance of in-plane tensile properties is TF18 group which pinned by full-depth Φ0.18mm diameter. The tensile strength increases by 5.32%, and the Young’s modulus increases by 4.71% relative to the control group. Compared with the group of large diameter Z-pin, the in-plane performance of the ultra-fine diameter group is better due to the less in-plane damage. In the half-depth group, delamination occurred between the middle Z-pin sublayer and the upper and lower layers, thus reducing the in-plane tensile property. The Poisson’s ratio increases in both full depth and half depth after Z-pinned and it is only related to insertion depth.