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| 氮掺杂石墨烯修饰丝网印刷电极测量油脂氧化诱导时间 |
| Determination of oxidation induction time of oil by N-doped graphene modified screen printed electrode |
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| DOI： |
| 中文关键词: 氮掺杂石墨烯 丝网印刷电极 油脂 氧化诱导时间 交流阻抗法 |
| 英文关键词:N-doped graphene screen printed electrode oil oxidation induction time AC impedance method |
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| 中文摘要: |
| 构建了一种氮掺杂石墨烯（NRG）修饰丝网印刷电极交流阻抗法测量油脂氧化诱导时间的新型测量体系。优化了电极组成和阻抗测量条件，研究了油脂阻抗值与过氧化值随时间的变化关系。结果表明：最优条件为导电碳浆配方为氧化石墨烯、碳纳米管、鳞片石墨粉和四乙氧基硅氧烷（TEOS）质量比为0.1∶?0.1∶?1∶?2，NRG修饰量3 μL，支持电解质为pH 7.0的磷酸盐缓冲液，体积比1∶?2的乙腈与磷酸盐缓冲液（pH 7.0）为萃取剂，油和萃取剂体积比1∶?1，流量1.5 mL/min，测量频率（5~8）×105 Hz。在最优条件下，萃取剂能较快速高效地萃取油脂氧化过程中产生的极性和弱极性氧化产物，所建立的测量体系能够灵敏地检测萃取相的阻抗值及其变化。由油脂氧化过程中阻抗值-时间曲线所得的氧化诱导时间，与由国标法所得的氧化诱导时间的相对偏差小于5%，F检验和t检验结果表明两种方法之间不存在系统误差。 |
| 英文摘要: |
| A novel measurement system for the determination of oxidation induction time of oil by nitrogen-doped graphene （NRG） modified screen printed electrodes with AC impedance spectroscopy (EIS) was constructed. The electrode composition and the conditions of impedance measurement were optimized, and the relation between impedance and peroxide value with time was studied. The results showed that the optimal conditions were obtained as follows: formula for conductive carbon paste of mass ratio of graphene oxide to carbon nano-tube to foliate graphite to Tetraetho-xysiloxane (TEOS) 0.1∶?0.1∶?1∶?2, NRG modification 3 μL, phosphate buffer liquid(pH=7.0) as the supporting electrolyte, acetonitrile and phosphate buffer liquid (pH=7.0) with volume ratio of 1∶?2 as extractant,volume ratio of oil to extractant 1∶?1, flow rate 1.5 mL/min and measurement frequency （5-8）×105 Hz. Under these conditions, the extractant could rapidly and efficiently extract the polar and weak polar oxidation products produced in the process of oil oxidation.The established measurement system could sensitively detect the impedance and its changes of the extracted phase. Moreover, the relative deviation between the oxidation induction time obtained from the impedance-time curve and from the national standard method was less than 5%. F-test and t-test revealed that there was no systematic error between the two methods. |
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