Maybe you can find some informations from the follwoing paper.

Nanoscale Research Letters 2014 9:62  DOI: 10.1186/1556-276X-9-62

Highly selective colorimetric detection and preconcentration of Bi(III) ions by dithizone complexes anchored onto mesoporous TiO2

thank you for your interest i have this paper but this paper not explain the condition of immobilization and he make metal- dithizone complex first after that the complex combine with nano particle but i need to immobilization of dithizone on nano particle after that dithizone and nano particle as sensor react with metals