Characterization of a hydrophilic-lipophilic balanced SPME material for enrichment of analytes with different polarities from aqueous samples

Abstract

The choice of the extraction material is a critical step in solid-phase microextraction (SPME), especially the extraction of analytes which strongly differ in their polarity is challenging. This study is intended to give first insights into the headspace extraction of analytes with large differences in polarity by using a novel hydrophilic-lipophilic-balanced (HLB) SPME material with different particle sizes (5 µm, 5 + 30 µm, and 30 µm) in classical SPME, as well as SPME arrow format. The obtained results were compared to conventional and already established divinylbenzene carbon wide-range polydimethylsiloxane (DVB-CWR-PDMS) and PDMS SPME arrow fibers. The chosen model analytes toluene, indole, phenol, anisole, o-xylene, naphthalene, 2-heptanone, n-dodecane, and lindane are assigned to different substance classes with K_aw values ranging from -5.0–2.5 and K_ow values from 1.5 to 7.5. The highest amount of the analytes was extracted by the HLB 5 + 30 µm arrow and the HLB 5 µm arrow, whereas the HLB SPME with a six times smaller phase volume compared to an SPME arrow, performed almost as well as the DVB-CWR-PDMS arrow. The 8-point calibration with the 5 + 30 µm HLB SPME arrow in the range of 5–70 µg L⁻¹ of the analytes showed good linearity with R² values ranging from 0.9765 to 0.9982, MDLs from 0.9 to 6.2 µg L⁻¹ and RSDs from 2 to 31 %. For all of the observed analytes, the HLB material performed better than the conventional extraction materials and has great potential to replace the conventional extraction materials in many applications.