GC-MS Analysis of n-hexane Extract of Roots of Aerva lanata (Linn) Juss. ex. Schult.

Context: The roots of the plant Aerva lanata are extensively used in Indian System of Medicine to cure urinary stones, antidiabetic, diuretic and used as demulcent. Aim: To investigate the phytoconstituents from the n-hexane extract of the roots of Aerva lanata using GC-MS analysis. Materials and Methods Roots of Aerva lanata was extracted by Soxhlet extraction method using n-hexane. The chromatogram was recorded by injecting the extract by splitless injection mode into the GC MS 5975 C Agilent equipped with a QP- 5000 (quadrupole) Gas Chromatography–Mass Spectrometer. Results: 23 phytoconstituents were identified by close matches with standard MS spectra and compared with NIST- 11 and WILEY library data from n-hexane extract. The major compounds reported are oleic acid (21.68%), γ-sitosterol (10.67%), Stigmasterol (5.13%), 3-β,5-α-stigmast-7-en-3-ol (4.23 %) and other constituents were found to be in traceable quantities. Conclusion: GC-MS analysis of roots of Aerva lanata revealed certain interesting facts of presentation of various phytoconstituents. The presence of various phytoconstituents contributes to the medicinal activity of the plant.

Preventing decomposition of 2-mercaptobenzothiazole during gas chromatography analysis using programmable temperature vaporization injection

2-mercaptobenzothiazole (MBT) is a chemical compound which is widely used in various processes in chemical industry, and it was also detected in environmental samples. Most of the researchers employed liquid chromatography (LC) or gas chromatography (GC) for determination of MBT. When GC was used, derivatization was necessary in order to prevent decomposition of MBT inside of the hot GC inlet. In this study, a new approach for preventing decomposition of MBT using programmable temperature vaporization (PTV) was presented. The sample was injected in a cold inlet (40?C) and the temperature was raised gradually until the analyte was evaporated. Contrary to hot splitless injection, no decomposition of MBT was observed using PTV. Compared to derivatization, PTV requires no chemicals and the duration of analysis is reduced.

Analysis of luwak coffee volatile by using solid phase microextraction and gas chromatography (Analisa senyawa volatil kopi luwak dengan menggunakan mikroekstrasi fase padat dan kromatolgi gas).

The approach to authenticate Luwak coffee is made through analysis of volatile compounds of luwak coffee. Luwak coffee bean from type of arabica obtained from Andungsari Plantation in Bondowoso district, East Java Province Indonesia, was wet processed and sundried prior to roasting step. As many as 120 g green bean was roasted at 170-220°C for 8-12 minutes until reached light brown colour (Agtron scale 65) and was ground prior to extraction. Volatile compounds of roasted Luwak arabica coffee bean were extracted by using solid phase microextraction (SPME) at 60°C for 30 minutes. The extracted analyte was subsequently transferred into GC-FID system by splitless injection at 260°C with five minutes sampling time, continued with separation through 50% phenyl 50% dimethylpolysiloxane capillary column and oven temperature programmed from 60°C to 180°C with rate of 5°C/min. Resulted chromatogram shows major peaks mainly in Rt 8.360-9.981, and Rt 9.705-14.778, and minor peaks identified before Rt 10 and after Rt 24. Varied sample quantity ranged within 0.5-2.5 g produced chromatograms which were not significantly different (p=0.08). This research also observed the use of γ-picoline (4-methylpyridine) as internal standard. It was showed that γ-picoline appeared at Rt 8.6~ without overlaying other peaks originated from sample. Concentration of γ-picoline at 0.05 μL/g, resulted separable peaks. These findings showed that the use of solid phase microextraction and GC-FID is capable to be apply for identification and quantification of Luwak coffee

Analysis of Car-3-en-5-hydroperoxide

HRGC-MS, using split/splitless injection (230°C), showed that a dioxygenase from Pleurotus sapidus regio-selectively transformed (+)-car-3-ene to car-3-en-5-one as the major volatile product to minor amounts of the corresponding alcohol, and to some other volatiles. Thus, the reaction was assumed to be radical mediated and similar to the lipoxygenase catalyzed peroxidation of polyunsaturated fatty acids, but the expected car-3-ene-hydroperoxides were not detected. TLC of the reaction products, followed by hydroperoxide specific staining, visually indicated the presence of hydroperoxides. TLC spots were eluted and re-analyzed using cool on-column injection, but only tailing peaks showing a mixed mass spectrum of car-3-en-5-ol/one were obtained. An unequivocal identification of car-3-en-5-hydroperoxides was achieved only after using APCI+-LC-MS. Upon structural confirmation, the car-3-en-5-hydroperoxide was accumulated by preparative HPLC, re-injected cool on-column, and the continuing degradation of the hydroperoxide to monoterpene ketone and alcohol during chromatography was verified. It was concluded that terpene hydroperoxides may occur in essential oils more frequently than anticipated, but are not recognized due to the principal blindness of capillary gas chromatography techniques and UV/vis LC-detectors.