Rapid colorimetric detection of potassium ions based on crown ether modified Au NPs sensor

Abstract Potassium ions (K+) play an important role in biological organisms. Therefore, efficient and sensitive detection of K+ in biological complex samples is crucial for disease diagnosis. Herein, we propose a novel sensor based on crown ether (4-aminobenzo-18-crown-6, ABC) modified Au NPs for rapid colorimetric detection of K+. Recognition of K+ and constitution of the aggregates are posed by a sandwich complex of 2:1 between ABC moiety and K+. Based on the aggregation mechanism, this colorimetric detection method has superior selectivity and anti-interference ability for potassium ions (K+) compared with other ions. There is a good linear relationship (R2 = 0.9979) in the range of 0–200 μM K+ concentration and this detection method can be successfully applied in the detection of K+ in real urine samples.