Sustainable Headspace-In-needle Microextraction Analysis of Phthalates Using Biomass-derived Carbon Coated Needles

Abstract

Phthalates as plasticizers are used in various products and pose environmental and health risks due to endocrine disruption potential. Detection of phthalates require appropriate sample preparation such as adsorption-based extraction. This study explores the conversion of withered flowers into activated hydrochar through hydrothermal carbonization and subsequent activation to utilize it as an adsorbent in in-needle microextraction for phthalates. The process involved hydrothermal carbonization of rose petals and stems followed by activation was optimized by the Box Behnken design and response surface methodology. The resulting activated hydrochar was applied as a coating for the interior of needle via sol-gel polymerization to form polydimethylsiloxane /activated hydrochar composite. The optimal conditions for hydrothermal carbonization and activation were identified as a reaction temperature of 210°C for 18 h using 7.5 g of withered rose followed by activation at 600°C with a melamine-to-biomass ratio of 1:1 and a potassium hydroxide-to-biomass ratio of 5:1 with subsequent analysis by GC-MS. The synthesized adsorbent was characterized using various analytical techniques including BET surface area analysis, FE-SEM, FT-IR spectrometry, and TGA. This innovative in-needle microextraction approach, optimized for headspace extraction, demonstrated efficient phthalate extraction. The method’s efficacy was validated through parameters such as LOD, LOQ, linearity, and recovery. It might be considered as a sustainable and effective sample preparation technique. The study shows that this method is easily fabricated, convenient for storage, cost-effective, and capable of detecting phthalates for advanced sample preparation.