An optosensor for riboflavin with C18 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 C18 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 (3σ-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.