A novel ultrashort capillary gas chromatography method using on-column injection and detection

A novel method for ultrashort capillary column gas chromatography (GC) analysis is introduced, which employs on-column injection and detection and rapid temperature programming. Using 10–20 cm long capillary columns, results showed that the method provides efficient and very rapid separations for relatively simple mixtures. Moreover, the on-column aspect of the method used here is demonstrated to avoid the extra column analyte degradation that can occur in traditional approaches to such separations. As a result, the developed method allows for the first time the GC analysis of some very large and (or) highly thermally labile analytes, such as polypeptides and drug molecules that are normally prone to decomposition. As an application, this method is further used to monitor pharmaceutical degradant formation as a function of temperature and was found to provide similar results to those obtained from conventional high-performance liquid chromatography analysis. Overall, the findings indicate that this ultrashort GC column approach could be useful in these areas and potentially others, where relatively simple GC analysis and universal flame ionization detection is desirable.

Study on the Determination of Cypermethrin Residues in Vegetable

The paper establish an analysis method for determination Cypermethrin pesticide residue in vegetable. Using acetonitrile to extract cypermethrin in vegetable, and purified by Agilent Florisil column, NH2 column and C18 column solid phase extraction column for the samples, using capillary column gas chromatography as a detection method, GC-ECD to qualitative analyze. The recovery rate of Cypermethrin is 91.2% ∼ 98% after Cleanert Florisil, the coefficient of variation is 0.53% ~ 3.67%, the detection limit is 0.0015 mg • kg -1. The first day, spraying the fenvalerate, dimethoate, chlorothalonil pesticides residues in lettuce was higher than the greenhouse tomato; pesticides (dimethoate, chlorothalonil, fenvalerate) residues in vegetables were higher than those in the open field, pesticide degradation speed is obviously higher than in greenhouse. Subsidence of pesticide is an important factor affecting greenhouse pesticide residues.