ABSTRACT
I. Introduction to solid phase dynamic extraction .................................. 156 A. Principles of SPDE............................................................................. 156 B. Instrumentation.................................................................................. 160 C. Technical aspects of SPDE................................................................ 161 D. Influence of parameters .................................................................... 161
1. Extraction parameters................................................................. 161 2. Desorption parameters ............................................................... 163 3. Summary of parameters............................................................. 163
E. Choice of polymer coating for the stationary phase ................... 164 F. SPDE extraction cooler for highly volatile compounds.............. 166
II. Applications................................................................................................ 167 A. Residues of packaging material in beverages............................... 167 B. Example: Cola..................................................................................... 170 C. Citral with SPDE................................................................................ 171 D. Volatile fractions of food matrices .................................................. 171 E. Amitraz in honey............................................................................... 178 F. Analysis of highly volatile compounds
with SPDE extraction ........................................................................ 179 III. Conclusions................................................................................................. 180 References ............................................................................................................ 180
A relatively new compromise between solid-phase microextraction (SPME) and stir bar sorptive extraction (SBSE) is generating significant interest in the U.S. food and flavor industry. Known as solid phase dynamic extraction (SPDE), the technique and associated tools were developed in 2000 by CHROMTECH GmbH of Idstein, Germany. Essentially, SPDE is an inside-needle technique for vapor and liquid sampling, which is as easy to apply and as reproducible as static headspace (S-HS) but with increased capacity and reduced sample handling. SPDE offers several inherent advantages over SPME and SBSE. Although SPME provides high extraction speeds and stability, one of its chief limitations is its reduced concentration capability, which is mainly due to the small volume of polymer that coats the fiber. In an SPME 100-
µ
m fiber, there is only about 0.6
µ
l of PDMS, whereas SPDE contains about 4.5
µ
l of the polymer. Other disadvantages of SPME include the fragility of its fused-silica, its unprotected stationary phase coating, and the limited flexibility of its surface area. Several attempts have been made to overcome these disadvantages. Most notably, in 1997, Ralf Eisert and Janusz Pawliszyn successfully introduced in-tube SPME-LC, in which sampling is conducted through an open tubular fused-silica capillary column.
