开链酰胺冠醚PVC膜钙离子选择电极研究

STUDY OF CROWN ETHER OF OPEN CHAIN DIAMIDE cALCIUM ION-SELECTIVE ELECTRODES

以8个不同结构的开链酰胺型冠醚（Ⅰ～Ⅷ,其中Ⅷ为环酰胺）为传感活性物质,研制了钙离子选择电极,其中以 N,N,N′,N′,-四环己基-3,6-二氧辛二酰胺（即冠醚Ⅱ）PVC 膜钙电极的综合性能最好,在缓冲溶液中测定,响应斜率:28 mV·（dec）-1线性范围:6.3×10-～10-mol·L-1CaCl2;检测下限:2.5×10-9mol·L-1CaCl2;在非缓冲溶液中,斜率为29.d mV·（dec）-1,线性范围;1.4×10-6～1×10-1mol·L-1。CaCl2,检测下限:7.4×10-7mol·L-1 CaCl2,对 Li+,Na+,K+,NH4+,Mg2+,Zn2+等干扰离子的选择系数分别为4.7×10-3,3.0×10-4,1.1×10-4,1.7×10-4,2.8×10-5,4.5×10-4.

Calcium ion PVC membranes selctive electrodes based on eight diamide compounds with different structure were prepared.Electrode of (Ⅱ) (N,N,N',N',-tetracyclohexyl-3,-6-dioxaoctane diamide)shows the best properties.In unbuffered solution,the linear response range,limit of detection and slope were 1.4×10^(-6)～1.0×10^(-1)mol·L^(-1),7.4×10^(-7)mol·L^(-1) CaCl_2 and 29.4 mV· (dec)^(-1).In buffered solution they were corresponding to 6.3×10^(-9)×1×10^(-3)mol·L^(-1),2.5×10^(-9) mol·L^(-1) and 28 mV·(dec)^(-1),respectively.The potentiometric selectivity confficients of Calcium ion for interfering ions Li^+,N^a+,K^+,NH_4^+,Mg^(2+)and Zn^(2+) (cone.o.1mol·L^(-1))were 4.7×10^(-3),3. 0×10^(-4),1.1×10^(-4),1.7×10^(-4),2.8×10^(-5) and 4.0×10^(-5) respectively using separate method.The response of this electrode was stable in a wide pH range (3.0～10.4).The average drift was 0.1～0. 2mV per hour in 10^(-3)mol·L^(-1) CaCl_2 over 8 hours.The excellent properties of this electrode more su- perior than electrodes based on other crown ethers including ETH 129 and very similar to ETH 1001.