A Newly Developed Magnetic Stir Bar Sorbent of Metal Organic Frameworks, Carbon Foam Decorated Zinc Oxide and Polyvinyl Alcohol Cryogel to Enrich and Extract Parabens and Bisphenols from Selected Drink Samples

A porous composite magnetic stir bar adsorbent was fabricated for the extraction and enrichment of parabens and bisphenols from selected beverage samples. The adsorbent comprised a metal organic framework, carbon foam decorated zinc oxide and magnetic nanoparticles embedded in polyvinyl alcohol cryogel. The porous composite stir bar adsorbent could adsorb parabens and bisphenols via hydrogen bonding, π-π and hydrophobic interactions. In the best conditions, linearity was good from 1.5 to 200.0 μgL-1 for methyl paraben, ethyl paraben and bisphenol A and from 3.0 to 200.0 μgL-1 for bisphenol B and butyl paraben. Limits of detection ranged from 1.5 to 3.0 μgL-1. The developed composite stir bar was successfully applied to extract and determine parabens and bisphenols in fruit juice, beer and milk. Recoveries ranged from 89.5 to 99.5% with RSDs lower than 6%. The developed sorbent and new methodology was evaluated in terms of its green character with satisfactory results.