Multiple solid-phase microextraction in a non-equilibrium situation

Multiple HS-solid-phase microextraction (MHS-SPME) is a modification of SPME developed for quantitative analysis that avoids possible matrix effects based on an exhaustive analyte extraction from the sample. In this paper, the theory of this process associated with a non-equilibrium situation has been presented. The application of an optimised HS-SPME-based method in the analysis of chloroanisoles and chlorophenols, previously acetylated, associated with the occurrence of cork taint in different red, white and rosé wine samples, has revealed the existence of matrix effects. This fact determines the choice of standard addition as the adequate technique for the quantification of these compounds in real samples. MHS-SPME is proposed as a good alternative technique with respect to HS-SPME because it avoids matrix effects, simplifies the quantification of these compounds in real samples and reduces analysis time, providing sensitivity below chloroanisole sensory threshold with acceptable precision.