Determination of icariin in urine by high performance liquid chromatography with tandem mass-spectrometric detection

C использованием метода высокоэффективной жидкостной хроматографии-тандемной масс-спектрометрии разработан способ селективного определения икариина в пробах мочи. Для анализа биологических проб использовали обращенно-фазовый вариант высокоэффективной хроматографии на сорбентах с привитыми C18 группами. Определение осуществляли методом тандемной масс-спектрометрии с ионизацией электрораспылением в режиме регистрации выбранных ионных переходов для положительных ионов (энергия соударений - 40 %, ионный переход - с m/z = 677.2433 → 313.0703 (100 %), 369.1330 (35 %)). Выбрана процедура пробоподготовки, включающая в себя твёрдофазную экстракцию на картриджах SUPELCO HLB, концентрирование органического экстракта в токе азота и перерастворение сухого остатка. Предел детектирования составил 1 нг∙мл⁻¹. При валидации методики оценивали степень извлечения икариина из биологической жидкости (97 %), селективность и специфичность определения целевого соединения, а также влияние матрицы на ионизацию (4 %).Using the liquid chromatography tandem mass spectrometry, the approach for the selective detection of icariin in urine samples was developed. Biological samples analysis was performed by the reversed-phase chromatography using the C18 sorbent. The method of tandem mass spectrometry with the multiple reaction monitoring (MRM) mode using the electrospray ionization technique in positive ion mode was used (the collision energy - 40 %, m/z = 677.2433 → 313.0703 (100 %), 369.1330 (35 %)). The sample preparation procedure comprising of the solid-phase extraction based on SUPELCO HLB cartridges, the evaporation of the organic extract in a stream of nitrogen and the reconstitution of residue was selected. The detection limit was 1 ng ml⁻¹. During the method validation, the extraction of icariin from a biological fluid (97%), the selectivity and the specificity of the target compound as well as the matrix effects of ionization (4 %) were studied

The Niujiaotang Cd-rich zinc deposit, Duyun, Guizhou province, southwest China: ore genesis and mechanisms of cadmium concentration

The Niujiaotang zinc deposit in southeastern Guizhou, China, is a Mississippi Valley-type Zn deposit within Early Cambrian carbonate rocks. Sphalerite is enriched in cadmium (average 1.4 wt.% Cd), which occurs mostly as isomorphous impurities in the sphalerite lattice. Discrete cadmium minerals (greenockite and otavite) are rare and are found almost exclusively in the oxidation zone of the deposit, probably formed as secondary minerals during weathering–leaching processes. Geochemical data show that the sulfides are enriched in heavy sulfur, with δ34S ranging from +10.0‰ to +32.8‰ (mean +22.5‰). The consistent Pb isotopic compositions in different sulfide minerals are similar to that of Cambrian strata. The ore lead probably came from U- and Th-rich upper crustal rocks, such as the Lower Cambrian Wuxun Formation. The ore fluid is of low-temperature (101°C to 142°C) type, with a Na–Ca–Mg–Cl-dominant composition, and is interpreted as oil-field brine. The data indicate that the metals were mainly derived from the Early Cambrian strata (Qingxudong and Wuxun Formations), whereas sulfur is sourced from sulfate in Cambrian strata or oil-field brines of the Majiang petroleum paleoreservoir. The genetic model for the deposit invokes an Early Cambrian shallow-sea environment on the Yangtze Platform. Zinc and Cd in seawater were concentrated in abundant algae via unknown biological mechanisms, resulting in large amounts of Znand Cd-rich algal ooliths. During the Ordovician, concurrent with destruction of the Majiang petroleum paleoreservoir, oil-field brines migrated from the center of the basin to the margin leaching metals from the Cambrian strata. In the Niujiaotang area, preexisting Zn and Cd, particularly in the Qingxudong and Wuxun Formation, were further mobilized by hot brines rising along the Zaolou fault system, forming stratiform and generally conformable Zn–Cd orebodies in reactive carbonate lithologies.Lin Ye, Nigel J. Cook, Tiegeng Liu, Cristiana L. Ciobanu, Wei Gao and Yulong Yan