• Journal of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.659-666
• /
• 1991

A systematic analysis of 18 stimulants and narcotic analgesics containing nitrogen atom (s) in human urine by gas chromatography with nitrogen phosphorus detector (GC-NPD), is described. The urinary extract with diethyl ether at pH 8.5 showed good recoveries of the drugs and less interference peaks on GC chromatogram. Retention data were standardized by the calculation of relative retention times using diphenylamine as the internal standard. The relative standard deviations of retention times were less than 0.1% for the within-run analyses. The response factor (RRF) of a drug relative to the internal standard was calculated. RRF decreased with increasing number of nitrogen atoms. This technique can be adapted to various analytical toxicology problems.

• Journal of Environmental Science International
• /
• v.6 no.4
• /
• pp.385-389
• /
• 1997

Pesticide residues were extracted with 70% acetone and transferred to dichloromethane. Extracts were applied to open-column chromatography with florisil and alumina-N. The final extract was analyzed by gas chromatography with electron-capture detector(GC /ECD) and nitrogen-phosphorus detector(GC/NPD). Recoveries of the 17 organochlorine pegticides were ranged from 60.8 to 84.9% and those of 15 organophosphate pesticides, from 70.5% to 100.0%(except phosmet and azlnphos-methyls. The minimum detectable levels of this analytical method were low(0.021-0.058mg/kg).

• Archives of Pharmacal Research
• /
• v.26 no.5
• /
• pp.416-420
• /
• 2003

The analytical method of antispasmodic agent tiropramide {$(\pm)\alpha$-(benzoylamino)-4-[2-(diethylamino)ethoxy]-N,N-dipropylbenzenepropanamide hydrochloride} was developed by gas chromatography/nitrogen-phosphorus detector (GC/NPD) in human plasma. Two kinds of tiropramide tablets were orally administered to volunteers by Latin square crossover design, and blood was withdrawn as designed schedule. The plasma of 1 mL was loaded on Sep-pak $C_{18}$ cartridge and eluted with methanol after washing with 30% methanol. The residue dissolved in 100 $\mu$L of methanol after evaporation was analyzed by GC/NPD. Precision (CV%) of intra-day was located within 2.6% and accuracy was less than 9.7%. Inter-day precision was below 8.7% and accuracy was relatively good as less than 14%. Plasma samples obtained from human volunteers were analyzed for the determination of tiropramide concentration by using this method. The method was sensitive, rapid and suitable enough to be applied for pharmacokinetic and bioequivalence studies of tiropramide in human volunteers.

• Journal of Environmental Science International
• /
• v.6 no.2
• /
• pp.183-187
• /
• 1997

Organophosphate pesticides were extracted with 70% acetone and then transferred to dichloromethane. Extracts were applied to open-column chromatography with florisil. The florial extract was analyzed by gas chromatography with nitrogen-phosphorus detector(GC/NPD). Recoveries of the 18 organophosphate pesticides were ranged from 88.7% to 100. 0% for the narrow-bore capillary GC(Ultra-21. The minimum detectable level of this analytical method was 0.019 - 0.035 mg/kg. Sample throughput(extraction, open-column chro- matography, and GC analysts) was decreased considerably (8h per sample).

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 1997.10a
• /
• pp.37-39
• /
• 1997

Pesticide residues were extracted with 70% acetone and transferred to dichloromethane. Extracts were applied to open-column chromatography with florisil and alumina-N, The final extract was analyzed by gas chromatography with electron-capture detector(GC/ECD) and nitrogen-phosphorus detector(GC/NPD). Recoveries of the 17 organochlorine pesticides were ranged from 60.8 to 84.9% and those of 15 organophosphorus pesticides, from 70.5 to 100.0%(except phosmet and azinphos-methyl). The minimum detectable levels of this analytical method were low (0.021-0.058 mg/kg).

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.895-900
• /
• 1995

Urinary free and acetylated polyamine profiles have been investigated for their potential usefulness as biochemical markers of cancer in a control of group comprised of healthy volunteers (32 cases) and patients with various types of cancers(48 cases). The nine (5 free and 4 acetylated) endogeneous polyamines were simultaneously determined by a sensitive capillary gas chromatography/nitrogen-phosphorus detector (GC/NPD). The newly modified (simple and convenient) method was developed and the compounds were isolated by adsorption onto silica gel and derivatized by heptafluorobutyric anhydride to enhance their specificity on gas chromatograms. The good quality-control data were obtained through the precision and accuracy test and the recovery range of them was 48.6 ~ 101.2 %. The Korean reference values of urinary polyamines were established and significant differences were found in cancer patients compared with normal subjects. Also, to eliminate subject variations, precursors to product concentration ratios were compared between cancer patients and control group. The ratios of both putrescine to spermidine and total (free plus acetylated) putrescine to total spermidine were significantly greater in cancer patients than in normal subjects.

• Journal of Environmental Science International
• /
• v.15 no.3
• /
• pp.229-236
• /
• 2006

Organophosphorus pesticides (OPPs) contents in the sewage sludge derived from the residential and industrial areas were determined in order to characterize contemporary organic contamination levels as a part of the ongoing development of the environmentally sound sewage sludge management strategy in Korea. OPPs were extracted from freeze-dried sludges in a ultrasonic extractor. The extracts were cleaned-up by florisil column and subsequently fed into gas chromatograph/nitrogen phosphorus detector (GC/NPD) for determining OPP contents. Diazinon, dimethoate, disulfoton, EPN, malathion, methyl parathion, parathion, phorate and sulfotep were present in the appreciable amount in the domestic sewage sludges. The sum of the 9 OPPs in the sewage sludge varied from 534.8 to 15552.1 ${\mu}g/kg$, dry wt..

• Food Science and Biotechnology
• /
• v.18 no.2
• /
• pp.471-474
• /
• 2009

Formaldehyde (FA) is a carcinogenic compound present in cigarette smoke. In this study, the amount of formaldehyde was analyzed in 5 kinds of cigarettes and the inhibitory effect of plant volatile extracts on the formation of FA was investigated. After extraction of the cigarette sample, FA was converted into its thiazolidine derivatives by reaction with cysteamine, and then measured using a gas chromatography-nitrogen phosphorus detector (GC-NPD). The concentrations of FA in cigarette smoke were found between 138.24 and $217.82{\mu}mol/g$ cigarette smoke. Extracts isolated from Welsh onion (Allium cepa L.), garlic (Allium sativum L.), crown daisy (Chrylsanthemum coronarium L.), green pepper (Capsicum annuum L.), and sesame dropwort (Oenanthe javanica DC) were used for analyzing their inhibitory effects on the formation of FA. The inhibitory effects of extracts of Welsh onion, garlic, crown daisy, green pepper, and sesame dropwort on the formation of FA were 64, 47, 38, 47, and 19%, respectively.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.5
• /
• pp.524-526
• /
• 1998

A sensitive and specific method is described for the determination of midazolam in human plasma. The drug was extracted from 1 mL of carbonate buffered plasma (pH 9.6) with 8 mL of diethyl ether. Famprofazone was used as internal standard. The organic phase was evaporated to dryness. The residue was dissolved in methanol for the direct analysis by gas chromatograph-nitrogen phosphorus detector system. In the concentration range of 1-5000 ng/mL, the calibration curve was linear. The coefficients of variation from the precision test were <6% at the range of the concentration of 0.10-2.00 μg/mL and the detection limit for midazolam in 1 mL of plasma was o.5 ng. This assay is more sensitive, selective, simple and rapid than earlier methods. Plasma midazolam concentrations were determined by this method after administration of midazolam.

• Environmental Analysis Health and Toxicology
• /
• v.16 no.4
• /
• pp.181-188
• /
• 2001

A gas chromatographic method was established for the simultaneous determination of urinary nicotine and cotinine. The analytes in basified urine containing a sufficient amount of Na$_2$S0$_4$were extracted into dichloromethane by vigorous shaking. Into the transferred organic phase was added a small amount of acidified methanol (0.5 N HCI in methanol), followed by concentrating the mixture to dryness using a mild stream of nitrogen gas. The concentrate was reconstituted with methanol and the final solution analyzed using the gas chromatograph equipped with the nitrogen-phosphorus detector. The reproducibility tests showed coefficients of variation less than 11％ for both compounds. The percent recovery for both analytes ranged from 88 to 103％. The estimated method detection limits for nicotine and cotinine were 0.60 and 5.1 ng/mL, respectively. Extraction efficiencies for both nicotine and cotinine apparently declined without the addition of Na$_2$S0$_4$into the urine. Moreover, the absence of methanolic HCI in the extract resulted in almost complete evaporation of nicotine and partial loss of cotinine during the concentration process, indicating that the formation of nicotine-HCI and cotinine-HCI species is prerequisite to the suppression of the loss of both compounds.