Fiber holder assemblies, SPME

FIGURE 11.17 SPME fiber holder assemblies (courtesy of Supelco, Inc., Bellfonte, PA). 

HS-SPME analysis of volatile compounds for food samples was performed according to a previously reported method applied to bread samples [29] with slight modifications. Similar conditions to those proposed by Blanda et al. [4] were used in the study with strawberries. The SPME fiber used was divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/ PDMS) 50/30 pm, StableFlex, 1 cm long mounted to an SPME manual holder assembly from Supelco (Bellefonte, PA) (Fig. 1). Prior to use, the fiber was conditioned by following the manufacturer s recommendations. The needle of the SPME device was inserted into the container through the septum and the fiber was exposed to the food sample headspace for 30 min at room temperature. The fiber was then retracted into the needle assembly, removed from the container, transferred to the injection port of the GC unit and immediately desorbed. 

The SPME apparatus looks like a modified syringe (see Fig. 5) consisting of a fiber holder needle and a fiber assembly, the latter equipped with a 1-2 cm long retractable SPME fiber. The fiber itself is a thin fused-silica optical fiber, coated with a thin polymer film (such as polydimethylsiloxane, PDMS), as shown... 

SPME holders with one of two fiber assemblies were used ... 

HSSPME Extraction Procedure. Manual SPME holders were used with a 100- am poly(dimethylsiloxane) (PDMS) and 65- am poly(dimethylsiloxane)-divinylbenzene (PDMS-DVB) fiber assembly (Supelco, Bellefonte, PA). The fibers were conditioned as recommended by the manufacturer. 

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