Automated needle-sleeve based online hyphenation of solid-phase microextraction and liquid chromatography

A novel approach for the online coupling of solid-phase micmextraction (SPME) and liquid chromatography (LC) is introduced. An innovative Si@GO@beta CD coated needle-sleeve extractant device was developed and then employed in the automated online SPME-LC-UV determination of estrogen-like isoflavones from human urine samples. The extractant SPME device is easily attachable at the endpoint of an analytical syringe needle and operated by a lab-made autosampler. Fully automated online SPME-LC is accomplished by proper autosampler programming to perform the following steps: i) the analytes extraction by direct immersion of the extractant device into the stirred sample, ii) a rinsing step iii) the analytes desorption/enrichment, iv) the online transference of the extract to the LC injection valve. Besides allowing the online SPME hyphenation, this extraction modality efficiently addressed the drawbacks associated with the clogging and dispersion of graphene-based microextraction techniques performed in packed-bed and dispersive formats. The main extraction parameters and the performance of the automated online SPME-LC method developed were carefully studied. The results show a good sensitivity, reliability, and straightforward analytical strategy for the determination of organic compounds in complex samples. The detection limit of the method was 20 mu g L-1 for DAI and 10 mu g L-1 for GEN, FOR and BIO. The intra-day RSD was below 10% and inter-day RSD was below 13%. The total analysis time was less than 17 min per sample.

Automated summary

A novel approach of online SPME-LC using a Si@GO@beta CD coated extractant device showed good sensitivity, reliability, and straightforward analytical strategy for the determination of estrogen-like isoflavones in human urine samples. The method addressed the drawbacks associated with graphene-based microextraction techniques and achieved a detection limit of 20 μg/L for DAI and 10 μg/L for GEN, FOR, and BIO with low RSD values. The total analysis time per sample was less than 17 minutes.