Comparative Study of SPME Method Performance on the Analysis of Mercury Species in Water : Integrated on-Fiber vs in-Matrix Derivatization

Author(s): Wan Mohd Afiq Wan Mohd Khalik, Md Pauzi Abdullah and Mohamed Rozali Othman

A comparison of derivatization step influence on the method extraction of mercury species has been carried out. Experimental design generated by using central composite design was used to optimize the extraction parameters. Signal response of targeted analytes, which accounts as sum of peak areas has shown maximum response (y = 276920, in-matrix derivatization) slightly higher compared to on-fiber derivatization (y = 274883). In both cases, two variables namely the concentration of solution and exposure time contribute significantly (ANOVA, p < 0.05). The time required for in-matrix derivatization to reach equilibrium is 0.9 min, slightly lower than on-fiber but similar value required for concentration of solution (1.4% m/v) and depth of fiber (49 mm) placed during extraction. Recovery for all species detected varied from 76-84% for in-matrix derivatization and 80-84% for on-fiber derivatization. For inorganic mercury trace level, analytical figure of merit namely recovery, repeatability and reproducibility better for on-fiber derivatization in the method extraction, as compared to in-matrix derivatization.

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