Application of Polyhydroxybutyrate-b-polyethyleneglycol (a block co-polymer) for Solid Phase Extraction of Lead and Copper in Different Food Samples (Sham K. Wadhwa, Tasneem Gul Kazi, Mustafa Tuzen, Hassan Imran Afridi, Naeemullah, & Kapil Dev Brahman , Trans.). (2014). Pakistan Journal of Analytical & Environmental Chemistry, 15(1), 66-73. https://doi.org/10.21743/