Polylactic Acid-polycaprolactone/graphene Bionanocomposites as Supersorbent for the Determination of Morphine, Codeine, and Methadone Drugs

A rapid and high-throughput method based on dispersed solid-phase microextraction coupled with GC/MS was developed for the determination of morphine, codeine, and methadone compounds from biological and aqueous samples. Bionanocomposites based on polylactic acid-polycaprolactone/graphene was prepared by melt mixing using an internal mixer with direct feeding method. In general, the weight ratio of the polylactic acid matrix phase to the polycaprolactone dispersed phase of the adsorbent was 70–30, and three weights of graphene (0.5, 1, and 2 wt% by weight of polymer) was used. The bionanocomposites were characterized by SEM, FTIR, and XRD. The XRD results showed that the graphene nanoparticles were well dispersed in the polymer matrix. The main variables with significant influence on extraction efficiency, such as graphene dosage, adsorbent dosage, extraction time, and desorption conditions, were studied by chemometric methods, including Box Behenken design and response surface methods. Under the optimum conditions, good linearity was obtained within the range of 5–2000 ng L⁻¹ for three analytes, with correlation coefficients > 0.9996. The developed method also showed good repeatability, RSD 3–8% (n = 3), for the spiked aqueous solutions at the concentration level of 40 ng L⁻¹.