A comparison of the volatile compounds in Rhizomes Curcumae (Ezhu) and Radix Curcumae (Yujin) was undertaken using gas chromatography-mass spectrometry (GC-MS). Ultrasonic extraction and GC-MS methods were developed for the simultaneous determination of five sesquiterpenes, namely, α-pinene, β-elemene, curcumol, germacrone and curdione, in Ezhu and Yunjin. Good linearity (r>0.999) and high inte...

A GC-MS with electron impact ionization was used for the development of a speciation method for the simultaneous determination of monobutyl-, dibutyl-, and tributyltin in environmental samples (waters, sediments, and biota). The method is based on the use of a mixed spike containing Sn-enriched monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) for isotope dilution analysis. The mixed ...

A simple, reproducible and efficient reverse phase high performance liquid chromatographic method was developed for simultaneous determination of valsartan and hydrochlorothiazide in tablets. A column having 200 x 4.6 mm i.d. in isocratic mode with mobile phase containing methanol:acetonitrile:water:isopropylalcohol (22:18:68:2; adjusted to pH 8.0 using triethylamine; v/v) was used. The flow ra...

A new silver nanoparticle modified screen-printed electrode was developed and applied to the simultaneous determination of Pb(II) and Cu(II). Two different types of silver nanoparticles with different shapes and sizes, Ag nanoseeds and Ag nanoprisms, were microscopically characterized and three different carbon substrates, graphite, graphene and carbon nanofibers, were tested. The best analytic...

Mathematical models that describe the retention reactions of contaminants in the soil system are presented. Single and multireaction-type models for simultaneous retention and transport in the soil profile are discussed. Single retention models are classified into two types: equilibrium and kinetic models. Emphasis is given to the nonlinearity and kinetic behavior of solute retention processes ...

the kinetic study of methylene blue (mb) adsorption using acid-activated spent tea (aast) as an adsorbent from aqueous solution with the aim of comparing linear and non-linear regression analysis methods was performed at varying initial mb concentrations (10-100 mg/l). hence, spent tea leaves, which were activated using concentrated sulfuric acid, were prepared. the physicochemical characterist...