Fig. 7: Sensor pH analysis and deployment in field samples.
From: Crown ether decorated silicon photonics for safeguarding against lead poisoning
a Pb2+ XPS analysis of the crown ether functional layer across a pH range of 2−8. b Optical fringe minima corresponding to 15 ppb of Pb2+ reference concentrations in DI water, with pH of 5, 6, 6.8 and 8. Optical fringe minima corresponding to the detection of Pb2+ via the photonic sensor in c, tap, and d, lake, and e, sea water. f XPS analysis of the crown ether functional layer when the sensor is subjected to DI, tap, lake and seawater.
