SLOVENIAN VETERINARY RESEARCH

Determination of malachite green and leucomalachite green in trout and carp muscle by liquid chromatography...85Method validationChromatograms demonstrating the selectivity ofthe procedure are shown in Figure 2, 3 and 4. In Figure2 chromatograms of blank sample and spikedsample of trout with LMG and LCV at 4 µg/kg areshown. LMG and LCV were separated with almostbaseline resolution. From chromatograms of blankand spiked sample of trout (Figure 3) and blank andspiked sample of carp (Figure 4) with MG and LMGat 4 µg/kg, it is evident that no interfering peaks fromendogenous compounds were found at the retentiontimes of the target analytes. Hence the selectivity ofthe procedure is considered satisfactory.(A)(B)Figure 2: Chromatograms of (a) trout muscle and (b) troutmuscle with a standard addition of LMG and LCV (4 µg/kg)Figure 3: Selectivity for the determination of MG and LMGin trout muscle tissue. (A) LMG: standard mixture 16 ng/mL, blank and blank with standard addition of 4 µg/kg (B)MG: standard mixture 16 ng/mL, blank and blank withstandard addition of 4 µg/kg.The results of the linearity of the LC-Vis/FLD responseand matrix calibration curve are reported inTable 1. The standard calibration curves are linearover the range 5-40 ng/ml and the matrix calibrationcurves were linear over the range 1-5 µg/kg for MGand LMG. The correlation coefficients of the standardand matrix calibration curves were greater than0.9993 for both MG and LMG.Table 1: Linearity of MG and LMG determination on standard and matrix levelStandardsTrout musclesAnalyte Slope Intercept Correlation coefficientMGLMGMGLMG6.593.498.565.62-3.67-1.16-3.871.320.99950.99990.99930.9998