The content of anions in environmental water, such as sulfate concentration, is an important index of water quality. Excessive sulfate concentration in drinking water can cause acute diarrhea. Polymer membrane ion selective electrode is widely used in real-time and rapid monitoring of environmental pollutants because of its high sensitivity, low cost and easy miniaturization, which is one of the important research directions in the field of environmental science. Unfortunately, due to the poor selectivity of sulfate ion electrode developed in recent years, lipophilic anions such as perchlorate and thiocyanate in environmental samples will cause great interference, so this kind of electrode can not be used in the actual environmental samples.

Recently, the team of Dr. Li Long and Professor Qian Yi, young teachers of School of environment, Qingdao University of science and technology, based on the previous research work (Analytical Chemistry, 2020,92 (21): 14740-14746; ACS sensors, 2020,5 (11): 3465-3473; ACS sensors, 2020,5 (11): 3465-3473; ACS sensors, 2020,5 (11): 3465-3473); Sensors and actuators B: chemical, 2020129151), developed a new type of sulfate carrier and constructed a high selective sulfate polymer membrane electrode. The related achievements were published in the international classic journal ACS with the title of "hydrogen bond based macrocyclic and tripodal neutral ions for highly selective polymer membrane sulfate selective electrodes" Sensors (top journals in District 1, if = 7.33).

In this paper, the ring and three-dimensional structure of ion carriers with high selectivity and strong binding ability to sulfate were constructed by designing the molecular space structure with squaramide and thiourea as hydrogen bonding donors, and the high selective sulfate ion selective electrode was constructed. The experimental results show that the new sulfate ion selective electrode has good selectivity and sensitivity, and the common anions such as perchlorate, thiocyanate and nitrate in environmental water do not interfere with the detection of sulfate ion. At present, the sensor has been successfully used for the determination of sulfate ion in drinking water. Qingdao University of science and technology is the first unit of this paper, and Dr. Li Long of School of environment is the corresponding author and the first author of this paper.

This work is supported by Shandong provincial key R & D program, Shandong Provincial Natural Science Foundation, Qingdao basic innovation project and State Key Laboratory, Key Laboratory of Chinese Academy of Sciences, collaborative innovation center of ecological chemical industry and Department of chemistry of Qingdao University of science and technology.