Determination of L-arginine content in Radix isatidis by a composite fluorescent probe of Pd (II)

Ultra-rapid capillary zone electrophoresis method for simultaneous determination of arginine and ibuprofen

The combination of arginine and ibuprofen is widely used for pain relief with a faster onset of action than conventional ibuprofen. Therefore, the determination of both compounds in a single run is highly desirable for rapid quality control applications. This paper reports an ultra-fast method (100 injections/h) for simultaneous determination of arginine and ibuprofen using capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation of arginine as cation and ibuprofen as anion was achieved using a background electrolyte composed by an equimolar mixture of 10 mmol/L of 2-(cyclohexylamino) ethanesulfonic acid and boric acid with pH adjusted to 8.4 using potassium hydroxide. The limits of detections were 5.3 and 10.0 μmol/L for arginine and ibuprofen, respectively. The proposed method is simple, fast (one analysis every 35 s), environmentally friendly (minimal waste generation) and accurate (recovery values between 95 and 98%).

Carbon nano-dots as a fluorescent and colorimetric dual-readout probe for the detection of arginine and Cu2+ and its logic gate operation

A new visual fluorescent probe based on carbon nano-dots (CNDs) has been facilely synthesized via one step microwave-assisted pyrolysis and utilized for sequential detection of arginine (Arg) and Cu²⁺ by fluorescent and colorimetric dual-readout assay. The fluorescence of CNDs can be effectively quenched by Arg, and recovered upon addition of Cu²⁺ due to the competitive binding of Arg and Cu²⁺ that leads Arg to escape from the surface of CNDs. The probe displayed high sensitivity and selectivity toward Arg and Cu²⁺ over other analytes with a low detection limit of 0.26 μM and 0.17 μM, respectively. Meanwhile, the CNDs can also give dual responsive signals of a visible color change (yellow-pink-light yellow). According to this phenomenon, an "AND" logic gate based on the novel CNDs has been constructed. More importantly, the probe was also extended to cellular imaging. The proposed method was simple with ease of operation, which demonstrated great potential in bio-sensing, disease diagnosis or environmental monitoring.