Using Cryogel to Prepare Poly(graphene-methylmethacrylate-ethylene glycol dimethylacrylate) as Adsorbents forGreen Sample Pretreatment

• Main Authors: Hou-Kuang Shih, 施厚光
• Other Authors: Jen-Fon Jen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/14262220782610487253

博士 === 國立中興大學 === 化學系所 === 103 === In this study, a novel poly(graphene-methylmethacrylate-ethylene glycol dimethylacrylate) (G-MMA-EGDMA) was synthesis by cryogel method and prepared as the adsorbents for pipette-tip solid phase extraction (PT-SPE) and stir bar sorptive extraction (SBSE), respectively, to increase the extraction efficiency and reduce the flow resistance. In the preparation of modified graphene polymer, the acrylate functional group was first modified on the graphene oxide, then mixed with methyl methacrylate and ethylene glycol dimethacrylate for cryogel polymerization in dimethyl sulfoxide (DMSO) at the temperature of 0.5oC. The modified graphene oxide was identified with infrared spectrum, and the porosity of copolymer was observed by SEM image. The porous graphene copolymer was prepared in a pipette-tip as the adsorbent for PT-SPE of six triazine herbicides in aqueous solution. Parameters affecting the extraction efficiency such as the pH of sample solution, the salt addition, the flow-rate for sample loading, rinsing solution and desorption solution were investigated thoroughly. Results indicate that the optimal conditions for PT-SPE of six triazine herbicides in 5 mL of aqueous solution at pH 7 with 0.2 % NaCl can be obtained with the flow-rate of 3 mL/min for sample loading, then rinsed with 1 mL of pure water, and eluted with 300 μL of acetone for the analysis with high performance liquid chromatography (HPLC) and ultraviolet (UV) detection. Under the optimal conditions, the limit of determination (LOD) and limit of quantitation (LOQ) for six triazine herbicides were below 0.4 ng/mL and 1 ng/mL, respectively. It only took less than 5 min for the PT-SPE of triazine herbicides. The relative standard deviations (RSD) were less than 7.8%. Recovery were between 90.6-103.5% and the RSDs were less than 9.3%. These results indicated that the poly(G-MMA-EGDMA) based PT-SPE is a rapid, sensitive, and eco-friendly sampling method. The porous graphene copolymer was prepared and coated onto the surface of a stir bar as the adsorbent for SBSE of bisphenol A and four alkylphenols in aqueous solution. Parameters affecting the extraction efficiency such as the pH of sample solution, the salt addition, the stirring-rate, the extraction time, and the desorption solution were investigated thoroughly. Results indicate that the optimal conditions for SBSE of bisphenol A and four alkylphenols in 50 mL of aqueous solution without salt-addition can be achieved with the stirring-rate of 400 rpm for 40 min extraction, then desorbed with 100 μL of ethanol for the analysis with HPLC-UV. Under the optimal conditions, the LOD and LOQ for bisphenol A and four alkylphenols were below 0.04 ng/mL and 0.1 ng/mL, respectively. The RSDs were less than 7.2%. Recovery were between 90.5-106.4% and the RSDs were less than 7.2%. These results indicated that the poly(G-MMA-EGDMA) based SBSE is a convenience, sensitive, and eco-friendly sampling method. In this study, poly(G-MMA-EGDMA) was successfully synthesized by cryogel and prepared as the adsorbents for PT-SPE and SBSE. From the performance of both proposed methods, it indicated that the porous poly(G-MMA-EGDMA) material is a high potential adsorbent for convenience, sensitive, and eco-friendly sample pretreatment methods.