Some trends in the development of microplasmas for spectrochemical analysis

The development of microplasmas for spectrochemical analysis by optical methods is discussed. Recent achievements in miniaturization are highlighted, especially for three types of plasmas, namely high-frequency plasmas, dc-discharges and microwave plasmas. The potentials of each of these groups of plasmas as sources for atomic emission spectrometry are discussed. Literature citations and experiments indicate that the plasmas are also very useful as atom reservoirs for atomic absorption spectrometry. Methods of sampling, including feeding with gas chromatography effluents, the use of electrothermal vaporization, and the evolution of gaseous species (as shown for the case of Hg vapor), are discussed as prominent interfaces to make use of these sources for elemental analysis.     

Synthesis and thermal decomposition of haloalkoxy-sym-triazines. 7. Thermal decomposition of 2-dialkylamino-4-(2-chloroethoxy)-6-methoxyamino-sym-triazines

Two 2-dialkylamino-4-(2-chloroethoxy)-6-methoxyamino-sym-triazines were synthesized. It was established that when they are heated at 120° C, the 2-chloroethoxy group undergoes rearrangement with cyclization to give 2-dialkylamino-4-oxo-8-methoxy-6, 7-dihydroimidazo [1,2-a]-sym-triazines, the structure of which was confirmed by data from the IR, PMR, and mass spectra.See [6] for Communication 6.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 8, pp. 1122–1124, August, 1981.     

A comparative study of several HPLC methods for determining free amino acid profiles in honey

A study of the viability of three derivatizing reagents for obtaining amino acid profiles in honey through high performance liquid chromatography (HPLC) is presented. A method using diode array detection based on a reaction with diethyl ethoxymethylene malonate (DEMM) and two other methods using fluorescence detection based on derivatization with fluorenylmethyl chloroformate (FMOC-Cl) and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) have been developed. The three methods yield detection limits close to the ppb level, but vary in relation to other analytical characteristics. The use of methyl chloroformate derivatives allows the profile to be obtained with the greatest sensitivity within a short time frame. On applying such methods to honey samples of diverse botanical origin, we observe that the proline values obtained are always lower than those found using the official spectrophotometric method, thereby underlining the advisability of using HPLC methods to reduce uncertainty in these results.     

Hydrocarbomethoxylation of 1-hexene with formic acid and methanol under conditions of phosphoric acid catalysis

Conclusions When the hydrocarbomethoxylation of 1-hexene with formic acid is run at atmospheric pressure and temperatures close to room temperature, in the presence of conc. H₃PO₄, an increase in the relative amount of the latter, as well as an increase in the reaction temperature in the investigated range, both favor an increase in the yields of the methyl esters of the C₇ acids, in particular, those containing two methyl groups on the quaternary carbon atom in the -position. An increase in the relative amount of formic acid also favors an increase in the amounts of these esters in the obtained mixtures of esters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1116–1118, May, 1971.