A porphyrin-based ratiometric SERS sensor for high-throughput and ultrasensitive cadmium ion detection.

We propose a novel method for highly sensitive SERS detection of Cd 2+ ions based on TMPyP-triggered Ag aggregates, which is achieved via a simple electrostatic interaction. In particular, this sensing system is relatively simple, but provides high sensitivity and excellent selectivity in a high-throughput fashion.