[Study of inorganic elements in silybum marianum: distribution and extraction rate].

The contents of multiple inorganic elements in silybum marianum products in different processing stages, including dry fruit, seedcake and extracts, were simultaneously measured by inductively coupled plasma atom emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The results indicated that the contents of the elements are the highest in the seedcake and the lowest in the extracts. Moreover, the different decoctions of Silybum marianum fruit made for different immersion times were determined. It was demonstrated that most of the elements measured are soluble, and the total content extracted for the first four immersion times is much higher than that for the latter three times. The certificate reference tea (GBW070605) was analyzed by this method, and the analysis results of most elements in the reference tea were in agreement with the certified values.

Determination of aluminum in environmental and biological samples by reversed-phase high-performance liquid chromatography via pre-column complexation with morin.

Morin was used as a pre-column reagent for the determination of aluminum by RP-HPLC with fluorescence detection. This method has been successfully applied to direct determination of trace Al in environmental and biological samples. The response was linear from 6 x 10(-9) to 6 x 10(-5) M with a detection limit of 2 x 10(-9) M. In addition, the different Al complexes with morin were separated by the proposed HPLC procedure and their coordination ratios were depicted by molar-ratio method. The results showed that 1:1 and 2:1 Al-morin complexes formed.

[Speciation of aluminum in natural waters by fluorimetry].

Fluorimetric method has been proposed for the speciation of Al in natural waters, based on the different competitive complexation behavior of analytical reagent and natural organic matter to Al. With eriochrome blue black R (EBBR) or morin, the monomeric inorganic Al (Al(i)) was determined, while with 8-hydroxylquinoline, the total monomeric Al (Al(a)) was obtained. The analytical results of Al speciation in natural water are close to those by Driscoll's method. The method is simple and reliable. Fractionation of Al was realized by selecting appropriate reagents under the pH of natural water determined. The merits of this novel strategy are that the disturbance to original equilibrium of Al species is minimized and the results conform to the actual situation of natural waters.

Morin applied in speciation of aluminium in natural waters and biological samples by reversed-phase high-performance liquid chromatography with fluorescence detection.

A reversed-phase high-performance liquid chromatographic method with fluorescence detection for the determination of labile monomeric aluminium has been developed through pre-column complexation using morin as the analytical reagent. The highly fluorescent aluminium-morin complex (excitation wavelength 418 nm, emission wavelength 490 nm) was separated on a Spherisorb ODS 2 column with an eluent consisting of 30% methanol and 70% water (pH 1.0 with perchloric acid). The most remarkable point of this protocol was that only the most toxic aluminium species, that is, free aqua-aluminium ion and its monomeric hydroxo complex ions, selectively respond among various aluminium complexes. This strategy has been successfully applied to direct fractionation of the toxic aluminium in natural waters and biological samples without any pretreatment.