Dependence of chromatographic retention indices on a ratio of amounts of target and reference compounds

Зенкевич, И. Г.; Ukolova, E. S.

doi:10.1016/j.chroma.2012.09.076

Cited by 13 publications

(4 citation statements)

References 30 publications

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“…They are based on a normalisation of the RT based on n-alkanes (Kovats) or PAHs (Lee) eluting before and after a chemical compound. Retention indices in GC exhibit excellent precision of < 0.5% under reproducible measurement conditions [349].…”

Section: Retention Index Use In Gcmentioning

confidence: 99%

NORMAN guidance on suspect and non-target screening in environmental monitoring

Hollender,

Schymanski,

Ahrens

et al. 2023

Environ Sci Eur

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Increasing production and use of chemicals and awareness of their impact on ecosystems and humans has led to large interest for broadening the knowledge on the chemical status of the environment and human health by suspect and non-target screening (NTS). To facilitate effective implementation of NTS in scientific, commercial and governmental laboratories, as well as acceptance by managers, regulators and risk assessors, more harmonisation in NTS is required. To address this, NORMAN Association members involved in NTS activities have prepared this guidance document, based on the current state of knowledge. The document is intended to provide guidance on performing high quality NTS studies and data interpretation while increasing awareness of the promise but also pitfalls and challenges associated with these techniques. Guidance is provided for all steps; from sampling and sample preparation to analysis by chromatography (liquid and gas—LC and GC) coupled via various ionisation techniques to high-resolution tandem mass spectrometry (HRMS/MS), through to data evaluation and reporting in the context of NTS. Although most experience within the NORMAN network still involves water analysis of polar compounds using LC–HRMS/MS, other matrices (sediment, soil, biota, dust, air) and instrumentation (GC, ion mobility) are covered, reflecting the rapid development and extension of the field. Due to the ongoing developments, the different questions addressed with NTS and manifold techniques in use, NORMAN members feel that no standard operation process can be provided at this stage. However, appropriate analytical methods, data processing techniques and databases commonly compiled in NTS workflows are introduced, their limitations are discussed and recommendations for different cases are provided. Proper quality assurance, quantification without reference standards and reporting results with clear confidence of identification assignment complete the guidance together with a glossary of definitions. The NORMAN community greatly supports the sharing of experiences and data via open science and hopes that this guideline supports this effort.

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Section: Retention Index Use In Gcmentioning

confidence: 99%

NORMAN guidance on suspect and non-target screening in environmental monitoring

Hollender,

Schymanski,

Ahrens

et al. 2023

Environ Sci Eur

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“…It is confirmed by the dependence of RIs vs . ratios of amounts of target analytes and reference constituents ( n ‐alkanes) , which is observed even at high dilutions of analyzed samples. It is noticeable that dependences RI( m ) for different analytes indicate no interpretative or visible anomalies around the overloading limit for the column under characterization (17 ± 4 μg).…”

Section: Resultsmentioning

confidence: 99%

“…The necessity of experimental evaluation of the overloading limits of GC columns can be illustrated by some examples. One of the principal factors responsible for interlaboratory reproducibility of retention indices (RI) is their dependence on the ratio of amounts (measured as ratio of areas of their peaks) of target analytes ( S x ) and reference compounds (usually n ‐alkanes, S n + S n +1 ) :

RI = R {normalI}_{0} + k ln (γ)

where γ = S x / ( S n + S n +1 ), k is a dimensionless coefficient, RI 0 is RI value that corresponds to equal peak areas of analyte and the two neighboring reference compounds, i.e. γ = 1. k values depend on the absolute amounts of analytes, but they are increasingly significant when approaching the overloading limits.…”

Section: Introductionmentioning

confidence: 99%

Overloading control of gas chromatographic systems

Зенкевич

Pavlovskii

2015

J. Sep. Science

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Increasing the interlaboratory reproducibility of gas chromatographic retention indices requires avoiding measurements distorted by overloading effects. Several criteria of evaluating the limits of the mass overloading of gas chromatographic systems are compared and reconsidered. The criteria mostly appropriate for practical purposes are based on (i) the dependences of factors of peak broadening (ratio of peak height and its width) vs. amount of analyte injected into the chromatographic column and (ii) the dependence of parameters characterizing the peak distortion (asymmetry factor) vs. the amount of analyte. Both these criteria provide mutually comparable evaluations of the overloading limits for analytes of different polarity. At the same time, the dependence of retention indices vs. amounts of analyte injected in the chromatographic column cannot be recommended for overloading control, because the parameters of the corresponding linear regressions indicate temperature dependence. The interpretation of certain gas chromatographic anomalies requires the correct evaluation of overloading limits. For example, the unusual temperature dependence of retention indices of polar analytes on non-polar stationary phases and the dependence of retention indices on ratio of amounts of target analytes and reference compounds.

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“…An efficient approach is to apply an additive scheme for the pre-calculation of the RI data (Zenkevich and Ukolova, 2012). In the framework of this contribution, linear temperature-programmed retention indices (Van den Dool retention indices) were determined rather than the isothermal RI values as proposed by Zenkevich.…”

Section: Structural Assignment Of Individual Isomersmentioning

confidence: 99%