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Circadian rhythm of spontaneous non-linear peptidization with proteinogenic amino acids in abiotic solutions versus homochirality

Maciejowska A., Godziek A., Sajewicz M., Kowalska T.

Acta Chromatographica

2017

Vol. 29, no. 1

135--142

In this short communication, we report on three striking phenomena of the circadian rhythm. One was observed with the non-linear concentration changes of the monomeric L-Cys and the non-linear yields of the L-Cys derived peptides, when undergoing spontaneous non-linear peptidization. The other one was observed with the binary L-Phe-L-Pro system, and the third one with L-Ser, D-Ser, and DL-Ser. So far, no analogous reports have been released on the circadian rhythm of the spontaneous non-linear peptidization of proteinogenic amino acids in a sterile abiotic environment (70% aqueous acetonitrile, or 70% aqueous methanol solutions). At the moment, we cannot find any rational explanation of this phenomenon, yet it seems highly probable that its origin is analogous to or even of a primordial nature for the circadian rhythm phenomena abundantly found in biological samples by other researchers. An experimentally established lack of the circadian rhythm with peptidization of the non-proteinogenic amino acid (D-Ser) can encourage us to revisit a still unsolved question of homochirality preconditions.

Determination of spectinomycin and related substances by HPLC coupled with evaporative light scattering detection

Wang Y, Wang M. J, Li J., Yao S. C, Xue J, Zou W. B, Hu C.

Acta Chromatographica

2015

Vol. 27, no. 1

93--109

An improved ion-pairing reversed-phase high-performance liquid chromatography method coupled with evaporative light scattering detection (HPLC-ELSD) was developed to determine spectinomycin and its related substances in commercial samples. The method was validated in accordance with International Conference on Harmonization (ICH) guidelines. The specificity of the HPLC-ELSD method was similar to that of the European Pharmacopoeia (Ph. Eur.) method, and repeatability and robustness were markedly improved relative to other reported methods due to our empirical evaluation of separation columns. Indeed, it is a more specific assay of spectinomycin than traditional microbiological techniques. The HPLC-ELSD method was used to evaluate the impurity profiles of eight compounds in seven spectinomycin batches from five different companies. Liquid chromatography coupled with electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was employed to characterize the structures of these compounds. Though the HPLC-ELSD method was not as sensitive as the Ph. Eur. method, its limit of quantitation (LOQ) (0.16%) was lower than the disregard limit (0.3%) described by the Ph. Eur. 7.0. This suggests that the HPLC-ELSD method is appropriate for routine analysis of spectinomycin and its related substances.

Simultaneous analysis of eight bioactive steroidal saponins in Gongxuening capsules by HPLC-ELSD and HPLC-MS n

Liu X. X, Wang L., Yang J., Zhang T. T., Deng X. D., Wang Q.

Acta Chromatographica

2009

Vol. 21, no. 2

327--339

Rapid high-performance liquid chromatographic methods with evaporative light scattering detection (HPLC-ELSD) and electrospray ionization multistage mass spectrometry (HPLC-ESI-MS n ) have been established and validated for simultaneous qualitative and quantitative analysis of eight steroidal saponins in ten batches of Gongxuening capsule (GXN), a widely commercially available traditional Chinese preparation. The optimum chromatographic conditions entailed use of a Kromasil C 18 column with acetonitrile-water (30:70 to 62:38, υ/υ ) as mobile phase at a flow rate of 1.0 mL min -1. The drift tube temperature of the ELSD was 102°C and the nebulizing gas flow rate was 2.8 L min -1. Separation was successfully achieved within 25 min. LC-ESI-MS n was used for unequivocal identification of the constituents of the samples by comparison with reference compounds. The assay was fully validated for precision, repeatability, accuracy, and stability, then successfully applied to quantification of the eight compounds in samples. The method could be effective for evaluation of the clinical safety and efficacy of GXN.