List of Articles Preconcentration Open Access Article Abstract Page Full-Text 1 - Preconcentration and Determination of Theophylline in Water Samples using Magnetic Nano-Cellulose with Dispersive Solid Phase Extraction Parastoo Molaei ali moghimi Shahin Ahmadi seyedali sobhanian Open Access Article Abstract Page Full-Text 2 - Preconcentration and Determination of Biperiden by using Solvent Bar Micro Extraction Combined with HPLC in Biological Fluids and Optimization by Chemometrics Design Melika Mohamadi persia behbahani Seyedali Sobhanian