A New, Rapid Gas Chromatography Method for the Detection of Basic Drugs in Postmortem Blood Using a Nitrogen Phosphorus Detector, Part II. Quantitative Analysis

Nicotine is a major addictive compound in cigarettes and is rapidly and extensively metabolized to several metabolites in humans, including urinary cotinine, considered a biomarker due to its high concentration compared to other metabolites. The aim of this study was to develop a single method for determination of urinary cotinine, in active and passive smokers, by gas chromatography with a nitrogen phosphorus detector (GC-NPD). Urine (5.0 mL) was extracted with 1.0 mL of sodium hydroxide 5 mol L-1, 5.0 mL of chloroform, and lidocaine used as the internal standard. Injection volume was 1 μL in GC-NPD. Limit of quantification was 10 ng mL-1. Linearity was evaluated in the ranges 10-1000 ng mL-1 and 500-6000 ng mL-1, with determination coefficients of 0.9986 and 0.9952, respectively. Intra- and inter-assay standard relative deviations were lower than 14.2 %, while inaccuracy (bias) was less than +11.9%. The efficiency of extraction was greater than 88.5%. Ruggedness was verified, according to Youden's test. Means of cotinine concentrations observed were 2,980 ng mL-1 for active smokers and 132 ng mL-1, for passive smokers. The results revealed that satisfactory chromatographic separation between the analyte and interferents was obtained with a ZB-1 column. This method is reliable, precise, linear and presented ruggedness in the range evaluated. The results suggest that it can be applied in routine analysis for passive and active smokers, since it is able to quantify a wide range of cotinine concentrations in urine.

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Screening and quantification of hypnotic sedatives in serum by capillary gas chromatography with a nitrogen-phosphorus detector, and confirmation by capillary gas chromatography-mass spectrometry.

Clinical Chemistry ◽

10.1093/clinchem/32.2.325 ◽

1986 ◽

Vol 32 (2) ◽

pp. 325-328 ◽

Cited By ~ 18

Author(s):

V A Soo ◽

R J Bergert ◽

D G Deutsch

Keyword(s):

Mass Spectrometry ◽

Gas Chromatography ◽

Capillary Gas Chromatography ◽

Gas Chromatography Mass Spectrometry ◽

Detector Response ◽

Capillary Gc ◽

Chromatography Mass Spectrometry ◽

Nitrogen Phosphorus Detector ◽

Sedative Drugs ◽

Nitrogen Phosphorus

Abstract We describe a quantitative screen for hypnotic-sedative drugs in which we use capillary gas chromatography with a nitrogen-phosphorus detector (GC/NPD) as the primary method and capillary gas chromatography-mass spectrometry (GC-MS) for confirmation. GC retention times of the acid-extracted underivatized drugs were stable (CVs less than 1%), and the detector response varied linearly over a 20-fold concentration range with a mean correlation coefficient for 11 drugs of 0.989. The limits of detection were satisfactory (0.5 mg/L in a 0.5-mL serum sample and 1-microL injection volume), as were precision (average CV 5.2% within day, 6.4% between day). The complementary use of capillary GC-MS not only unambiguously confirms presumptive peaks identified by GC, but also prevents reports of false positives and identifies compounds not included in the quantitative GC screen that may be listed in the GC-MS library.

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Nitrogen-containing aromatic compounds: quantitative analysis using gas chromatography with nitrogen phosphorus detector

Applied Petrochemical Research ◽

10.1007/s13203-021-00265-z ◽

2021 ◽

Author(s):

Yuan Rao ◽

Arno de Klerk

Keyword(s):

Gas Chromatography ◽

Quantitative Analysis ◽

Aromatic Compounds ◽

Process Development ◽

Complex Mixtures ◽

Response Factors ◽

Cyanide Anion ◽

Nitrogen Phosphorus Detector ◽

Assurance Process ◽

Nitrogen Containing Compounds

AbstractThe nitrogen-containing aromatic compounds found in the petrochemical industry are varied and extend beyond classes such as the anilines, pyrroles and pyridines. Quantification of these nitrogen-containing compounds that may occur in complex mixtures has practical application for quality assurance, process development and the evaluation of conversion processes. Selective detection of nitrogen-containing species in complex mixtures is possible by making use of gas chromatography coupled with a nitrogen phosphorous detector (GC-NPD), which is also called a thermionic detector. Despite the linearity of the NPD response to individual nitrogen-containing compounds, the response factor is different for different compounds and even isomers of the same species. Quantitative analysis using an NPD requires species-specific calibration. The reason for the sensitivity of the NPD to structure is related to the ease of forming the cyano-radical that is ionized to the cyanide anion, which is detected. The operation of the NPD was related to the processes of pyrolysis and subsequent ionization. It was possible to offer plausible explanations for differences in response factors for isomers based on pyrolysis chemistry. Due to this relationship, the NPD response can in the same way be used to provide information of practical relevance beyond its analytical value and a few possible applications were outlined.

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