一种基于钴的丝网印刷磷酸盐传感器研究

A disposable cobalt-based phosphate sensor based on screen printing technology

采用丝网印刷技术制备用于水中磷酸盐检测的传感器,其中,掺有钴粉的碳浆为工作电极,银/氯化银浆为参比电极.在25℃下,对于用pH为4.0邻苯二甲酸氢钾(KHP)缓冲溶液配制的浓度梯度为1×10-5～0.1mol/L的KH2PO4溶液,钴碳比为1:7磷酸盐丝网印刷电极有良好的能斯特响应,响应斜率为-41.63mV/decade,检测限为5×10-6mol/L,响应时间为60s,稳定性较好.丝网印刷电极的重现性很好,测量同一溶液,同一钴碳比的丝网印刷电极的相对误差小于1%,不同钴碳比的丝网印刷电极的相对误差小于3.5%.

A cobalt-based phosphate sensor was successfully fabricated by using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consisted of fully integrated cobalt （Co） electrode,which was a layer of carbon conductive ink （C） physically doped with Co powder,and Ag/AgCl reference electrode. At 25℃ and the Co/C ratio of 1：7,the cobalt-based phosphate sensor showed strong stability and phosphate-selective potential response was in the range of 1×10-5 mol/L to 10-1 mol/L,yielding a detection limit of 5×10-6 mol/L and a slope of -41.63 mV/decade in acidic solution （pH 4.0,potassium hydrogen phthalate buffer） for H2PO4-.The response time of the screen-printed electrode was about 60s. The proposed screen printed sensor also exhibited significant reproducibility with a small repeated sensing deviation （i.e. relative standard deviation （R.S.D.） 1%） on a single sensor and a small electrode-to-electrode deviation（i.e. R.S.D.3.5%）.