Quantitative gas chromatography using peak heights and relative response factors. An undergraduate student experiment

Представлены формулы для расчета коэффициентов относительной чувствительности RRF (relative response factors) и поправочных коэффициентов F (correction factors) примесей, а также формулы, необходимые для понимания сущности коэффициентов RRF и F. Рассмотрены основные способы определения поправочных коэффициентов и их ограничения (условия, выполнение которых необходимо для корректного определения RRF и F). Эти ограничения не отражены в Европейской фармакопее и в Фармакопее США, но от их учета зависит правильность определения значений поправочных коэффициентов. Приведены примеры и даны рекомендации для надежного определения и правильного использования поправочных коэффициентов.

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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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