• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.406-408
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• 1985

n-Hexanal in headspace over the cooked brown rice stored at $5^{\circ}C$ and $35^{\circ}C$ for 0. 4, 8 and 12 months was determined by a modified direct vapor injection gas chromatographic method. The retention time of n-hexanal was 3.5 min and n-hexanal could be rapidly separated from other compounds at the operational conditions of gas chromatography. n-Hexanal contents of cooked brown rice also showed a standard deviation of less than 10% of the average.

• KSBB Journal
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• v.18 no.1
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• pp.74-77
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• 2003

A simple, reproducible, and rapid gas chromatographic method for putrefactive metabolite determination in feces was developed. The method involves the direct injection of fecal supernatants into the gas chromatograph, without pretreatment. The mass spectra of these metabolites were obtained using an HP 5971 mass selective detector operated in electron impact (EI) ionization mode. This method produced sharp peaks and allowed the simultaneous determination of fecal putrefactive metabolites.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.299-306
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• 1993

Determination of dietary fiber contents in some Korean foods was attempted by Englyst's gas chromatographic and colorimetric methods which measure the nonstarch polysaccharide (NSP) contents NSP values, except seaweeds, by gas chromatography (x) and colorimetry (y) were very closely correlated (y=1.01x-0.52, r=0.997, n=9), NSP values by gas chromatography were lower than total dietary fiber (TDF) Haloes by AOAC method. By adding lignin to NSP values, relation between the two methods was improved. But, TDF values (y) by adding lignin to NSP values and TDF values (x) by AOAC method were related as y=0.68x-0.64 and F=0.903(n= 12), which was not closely related.

• Analytical Science and Technology
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• v.12 no.2
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• pp.136-140
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• 1999

Lupenone and lupeol, the triterpenoids of Sorbus Cortex, were isolated with silica gel column chromatography and used as the standard substances for the quantitative analysis. The compounds were identified with IR, NMR, EI-MS. They were separated on VA-5MS [(5%-phenyl)methylpolysiloxane, $30m{\times}0.25mm$, $0.25{\mu}m$] column by gas-chromatograph. The contents of lupeone and lupeol in three different samples of Sorbus Cortex were in the range of 0.050~0.056% and 0.772~0.834%, respectively.

• Journal of Nutrition and Health
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• v.7 no.4
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• pp.12-20
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• 1974

Quantitative analysis was achieved by gas-liquid chromatographic method (GLC) with a single column system of OV-17 for 16 of protein amino acids in mushroom (agaricus bisporus). The quantities of protein amino acids in mushroom were determined $48.32{\sim}255.94mg%$ alanine, $108.6F{\sim}364.82mg%$ glycine, $124.30{\sim}314.17mg%$ Valine, $32.99{\sim}418.79mg%$ leucine and isoleucine, $151.78{\sim}669.07mg%$ threonine, $88.12{\sim}4F6.3Fmg%$ Serine, $21.9F{\sim}114.94mg%$ Hydroxyproline, $20.F4{\sim}174.63mg%$ proline, $34.52{\sim}173.59mg%$ Methionine, $225.25{\sim}1417.61mg%$ Aspartic Acid, $10F.00{\sim}392.17mg%$ Phenylalanine, $12F.46{\sim}535.65mg%$ Glutamic Acid and Lysine, Tyrosine in trace amount.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.115-121
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• 1992

In order to broaden the spectrum of substrate utilization of a Gram negative bacterium Zymomonas mobilis which has a great potential as an industrial ethanol producing microorganism, cloning of $\alpha$-amylase gene into Z. mobilis ZM4 was tried. The $\alpha$-amylase gene was isolated from Bacillus stearothermophilus. By Southern blot analysis, it was proven that the $\alpha$-amylase gene fragment was originated from a naturally occuring plasmid of B. stearothermophilus ATCC 31195. To place $\alpha$-amylase gene under the control of Z. mobilis promoter, two different Z. mobilis expression vectors, pZA26 and pLOI204, were used. The truncated $\alpha$-amylase gene was then introduced into these vectors. Both qualitative and quantitative activities of $\alpha$-amylase were observed in Z. mobilis cells harboring these plasmids with the $\alpha$-amylase gene inserted. Gas chromatographic analysis of ethanol showed that one of the Z. mobilis transconjugants was capable of producing 67 mM ethanol from rich medium(RM) containing 5% soluble starch as a sole carbon source.

• Journal of Food Hygiene and Safety
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• v.9 no.2
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• pp.89-94
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• 1994

A simple, safe, and sensitive gas chromatographic method using packed column and electron capture detector to analyze 2, 4-D herbicide in imported lemon, grapefruit, and orange was described and its usefulness evaluated. In this scheme of analysis the acid herbicide was converted into its alkyl esters by an one-step reaction prior to analysis. The herbicide in the fruits was extracted with ethyl acetate and partitioned against dichloromethane for purification, and the extracts finished partitioning were derivatized with alcohol, using sulfuric acid as a catalyst to form the corresponding alkyl derivatives. The analytical scheme studiedwas found to be applicable for the herbicide in the fruits without a column clean-up procedure. The mean recoveries of the herbicide for lemon samples fortified at 0.1 mg/kg and 1.0 mg/kg were 93% and 95%, respectively. The detection limit was 0.5 $\mu\textrm{g}$/kg for 2.4-D methyl ester.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.245-250
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• 2004

An analytical method was developed to determine monocrotophos residues in apple, citrus, and soil using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. Monocrotophos was extracted with acetone from apple, citrus and moist soil samples. The extract was concentrated, added with saline water, and subjected to n-hexane washing to remove nonpolar co-extractives. Dichloromethane partition was then followed to recover monocrotophos from the aqueous phase. Silica gel column chromatography was employed to further purify the extract prior to HPLC determination. Reverse-phase HPLC using an oct-adecylsilyl column was successfully applied to separate and quantitate the monocrotophos residue in sample extracts at the wavelength of 230 nm. Overall recoveries of monocrotophos from fortified samples averaged $95.3{\pm}2.1%$ (n=6), $970{\pm}0.7%$ (n=6), and $92.8{\pm}4.3%$ (n=12) for apple, citrus, and soil, respectively. The proposed method was quite reproducible and sensitive enough to replace the troublesome gas-liquid chromatographic analysis for monocrotophos residues.

• Archives of Pharmacal Research
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• v.5 no.2
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• pp.71-77
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• 1982

Improvements in the analytical methodology used in the gas chromatographic/mass spectral analysis of phenolic compounds from cigarette smoke are described. For the direct analysis of crude samples, pyridine extraction and the glass capillary column GC was used for the separation of phenolics as trimethylsilyl derivativatives. The separations of cigarette smoke on Carbowax 20M and SE-54 wall coated open tubular columns are given. Improved methodology for the routine quantitation of the identified components using the computer-controlled multiple ion selection technique of MS presented. Considerations pertaining to routine analyses of a multitude of complex smoke samples are also discussed.

• Analytical Science and Technology
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• v.37 no.2
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• pp.123-129
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• 2024

We present a rapid method for the determination of Cs, Sr, and Ba, heat generators found in highly active liquid wastes, by gas-pressurized extraction chromatography (GPEC) using a column containing a cation-exchange resin. GPEC is a microscale column chromatographic technique that uses a constant flow rate of solvent (0.07 mL/min) with pressurized nitrogen gas supplied through a valve. In particular, because this method uses a small sample volume (a few hundred microliters), it produces less chemical waste and allows for faster separation compared to traditional column chromatography. In this study, we evaluated the separation of Cs, Sr, and Ba using GPEC. The eluate from the column (GPEC or conventional column chromatography) was quantitatively analyzed using inductively coupled plasma-mass spectrometry to measure the column recovery and precision. The column reproducibility of the proposed GPEC system (RSDs of recoveries) ranged from 2.7 to 4.1 %, and the column recoveries for the three elements ranged from 72 to 98% when aqueous HCl was used as the eluent. The GPEC results are slightly different in efficiency and separation resolution compared to those of conventional column chromatography because of the differences in the eluent flow rate as well as the internal diameter and length of the column. However, the two methods had similar recoveries for Cs and Sr, and the precision of GPEC was improved by two-fold. Remarkably, the solvent volume required for GPEC analysis was five times lower than that of the conventional method, and the total analysis time was 11 times shorter.