An optosensor for riboflavin with C-18 silica gel as a substrate

A flow-through optosensor for the sensitive determination of riboflavin in some pharmaceutical preparations was developed. The sensor was developed in conjunction with a flow-injection analysis system and uses C-18 silica gel as a substrate. The wavelengths of excitation and emission were 466 and 515 nm, respectively. The applicable concentration range was 2.2-91.8 ng ml(-1) with a detection limit (3 sigma-criterion) of 0.4 ng ml(-1). The relative standard deviation for ten determinations of 15 ng ml(-1) of riboflavin was 1.1%. The method is more sensitive than other methods described in the literature.