Analysis of Chemical Constituents of Volatile Oil of Se-Enriched Selenium Codonopsis tangshen Oliv. GC-MS

Objective : Codonopsis tangshen Oliv.is a kind of traditional Chinese medicinal materials high medicinal purposes value and wide application.It had important meanding to analyze its volatile oil consitituent on expanding its utilization and increasing the added value.Methods:The volatile compounds of Codonopsis tangshen Oliv. were isolated with steam distillation,and identified by capillary GC／MS and the relative contents of the constitons were detemined by area normalization method. Rusults: 60 volatile components were identified and determined，accounting for98.51％ of the total area of the peaks.Conclusion: The main volatile compounds are :Decanoic acid 2-monoglyceride,Furfural,Isopentyl alcohol,Palmitic acid,eugenol methyl ether,Di-sec-butyl ether,Hydroperoxide, 1-methylhexyl,Hexanoic acid ,2,4,5-trimethyl-1,3-Dioxolane ,Propasol solvent P,Hexyl alcohol ,cis-Isosafrole ,2-Hexenal ,Cajeputol.

Solid phase extraction and spectrophotometric determination of palladium with 2-(2-quinolylazo)-5-diethylaminobenzoic acid

A sensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II) with 2-(2-quinolylazo)-5-diethylaminobenzoic acid (QADEAB) and the solid phase extraction of the Pd(II) -QADEAB chelate with a reversed phase polymer-based C18 cartridge was developed. In the presence of 0.05 - 0.5 mol/L of hydrochloric acid solution and cetyl trimethylammonium bromide (CTAB) medium QADEAB reacts with palladium(II) to form a violet complex with a mole ratio 1:2 (palladium to QADEAB). The chelate was enriched by solid phase extraction with a reversed phase polymer-based C18 cartridge. An enrichment factor of 200 was obtained by elution of the chelate form the cartridge with the minimal amount of isopentyl alcohol. The molar absorptivity of the chelate in the isopentyl alcohol medium was 1.43?105 L mol-1 cm-1 at 628 nm. Beer?s law was obeyed in the range of 0.01-1.2 ?g/mL. The relative standard deviation for eleven replicate samples at the 0.2 ?g/L level was 2.18 %. The attained detection limit amounted to 0.02 ?g/L in the original samples. This method was applied to the determination of palladium in environmental samples with good results.

Pararosaniline as a New Chromogen for the Extractive Spectrophotometric Determination of Trace Amounts of Hydrogen Sulfide in Air

A sensitive spectrophotometric method for the determination of trace amounts of hydrogen sulfide H2S) in air, after fixing in a zinc acetate–disodium ethylenediaminetetraacetate–sodium hydroxide solution, is described. The reaction of iodate with the fixed H2S in the presence of acid and an excess of chloride leads to the formation of ICI2 ions. The resulting IC-2 species forms an ion par with pararosaniline cation, and the product is extracted into isopentyl alcohol. The color system obeys Beer’s law over the range of 0 to 5.0 μg H2S. The molar absorption coefficient of the color system is 1.8 × 104 L mol-1 cm-1 . The coefficient of variation is 3.3% for 10 determinations at 3.0 μg H2S. The effect of interfering gases on the determination is discussed. The method was applied to the determination of residual amounts of H2S present in a laboratory fume cupboard, and results were compared to those obtained by the widely used methylene blue method. The current method can be used to determine residues as low as 0.2 μg H2S.

Extractive Spectrophotometric Determination of Trace Amounts of Sulfur Dioxide in Air

A sensitive spectrophotometric method was developed for the determination of trace amounts of sulfur dioxide (SO2) in air after SO2 has been fixed in a buffered formaldehyde solution. The reaction of iodate with the fixed SO2 in the presence of an acid and an excess of chloride leads to the formation of ICI2 ions. The resulting ICI2 species forms an ionpair with pararosaniline cation; the product is extracted into isopentyl alcohol and measured spectrophotometrically at 560 nm. The color system obeys Beer's law over the range 0-40 μg SO2. The color is stable for 72 h from the time of extraction. The molar absorption coefficient of the color system is 4.5 x 103Lmol"1cm"1. The coefficient of variation is 3.6% for 10 determinations at 20 μg SO2. The effect of interfering gases on the determination is discussed. The method was applied to the determination of SO2 at low concentrations, and the results obtained were compared with the widely used West and Gaeke method. The method can be used to determine as low as 2 μg S02