Application of Gas Chromatographic Retention Indices to GC and GC-MS Identification with Variable Limits for...

Area of Science:

• Analytical Chemistry
• Chromatography

Background:

• Gas chromatography relies on retention indices (RIs) for compound identification.
• Current methods for comparing experimental and reference RIs have limitations due to fixed deviation values.
• Uncertainty in RI comparisons can arise from variations in chromatographic conditions and reference data.

Purpose of the Study:

• To introduce a novel algorithm for comparing experimental and reference gas chromatographic retention indices.
• To address and minimize uncertainties associated with fixed deviation limits in RI comparisons.
• To enable more accurate and flexible data analysis in gas chromatography.

Main Methods:

• Developed an algorithm that calculates deviations (ΔRI) for identified analytes with known reference RIs.
• Employed regression analysis (ΔRI = aRI_exp + b) to establish data-dependent adaptive thresholds.
• Recalculated experimental RIs to corrected values (RI_corr = RI_exp + ΔRI).

Main Results:

• The algorithm replaces fixed, global deviation limits with adaptive thresholds tailored to specific analytes and chromatogram regions.
• Enables reliable comparison of RIs across different nonpolar polydimethylsiloxane stationary phases (e.g., standard vs. semi-standard).
• Minimizes the impact of potential errors in reference RI data and is applicable to both statistical and single-measurement reference data.

Conclusions:

• The proposed algorithm offers a more robust and accurate method for comparing gas chromatographic retention indices.
• It enhances the reliability of compound identification in complex mixtures by adapting to data-specific uncertainties.
• The algorithm is compatible with existing RI databases and measurement practices.