A novel and selective assay for the quantitative analysis of molybdenum(VI) at nanogram level by resonance light scattering quenching technique.

A novel method is designed for the direct determination of trace amounts of molybdenum(VI) in tap water, human hair, and Chinese herbal medicine by means of decreasing resonance light scattering (RLS) technique. The characteristics of RLS spectra, the effective factors, and optimum conditions of the reaction were studied. In the medium of hydrochloric acid (pH 2.38), Mo(VI), dibromohydroxyphenylfluorone (DBHPF), and Triton X-100 react to form a complex, resulting in significant decreasing RLS signals of DBHPF-Triton X-100. The decreasing RLS intensity at 583.0 nm is proportional to the concentration of Mo(VI) up to 8.0 ng mL(-1). The detection limit is 0.013 ng mL(-1). The method is simple, reproducible, with reaction rapidity and stability of complexes formed. Moreover, the high selectivity and sensitivity of this method permits its direct determination of molybdenum(VI) in tap water, human hair, and Chinese herbal medicine and the results are in agreement with those obtained by the inductively coupled plasma atomic emission spectrometry (ICP-AES) method.

[Study on BS-12 as a new probe for the determination of DNA by resonance light scattering].

A new method has been developed for the determination of DNA by resonance light scattering with dodecyl dimethyl betaine (BS-12) in aqueous solution as a new probe. At pH 9.3, the interactions of BS-12 and DNA gave strong RLS signals at 388.0 nm. Linear relationships were found between the enhanced intensity of RLS and the concentration of DNAs in the range 0.25-12.0 microg x mL(-1) for fsDNA and 0.25-11.0 microg x mL(-1) for ctDNA. The limits of detection were 0.15 ng x mL(-1) and 0.16 ng x mL(-1) for fsDNA and ctDNA, respectively. The method was applied to the determination of synthetic samples with satisfactory results.