Determination of l-phenylalanine by cucurbit[7]uril sensitized fluorescence quenching method

The determination method of l-phenylalanine (LPA) by fluorescence quenching was developed. The assay was based on the combination of the cucurbit[7]uril (CB[7]) with palmatine hydrochloride (PAL) reaction. In the presence of CB[7], the fluorescence of PAL was quenched by LPA which can be employed to detect LPA. Under the optimal conditions, a linear range 3.63 × 10−8–9.68 × 10−6 mol/L and a detection limit 1.27 × 10−8 mol/L of LPA were obtained. The relative standard deviation (R.S.D) was 1.8% obtained from a series of 11 standards each containing 6.05 × 10−6 mol/L of LPA. This paper also discusses the mechanism of fluorescence indicator probe.