### Abstract

Temperature dependence of the Kováts retention index (I) was measured for some aliphatic ketones and aldehydes on a poly(dimethyl siloxane) (HP-1) stationary phase. An interesting minimum (non-linearity) was observed for the I versus isothermal column temperature (T) relationships. A novel empirical model is proposed: I=A+B/T+ClnT, where A, B and C are equation constants and B/C=T_{min}. A detailed statistical analysis clearly shows superiority of the extended model (i.e., of this containing the logarithm of the temperature (lnT) term) over the earlier established Antoine-type reciprocal equation. The minimum temperature (and the energy like quantity=RT_{min}, where R is the gas constant) changes in a systematic manner. The factors effecting the (RT_{min}) term are as follows: (i) this term decreases with the increase of the molecular mass of the respective oxo compounds; (ii) ketones have higher absolute values of (RT_{min}) than aldehydes; (iii) branching of the carbon chain lowers the mentioned (RT_{min}). This enthalpy term is unambiguously bound to the polarity of solutes.

Original language | English |
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Pages (from-to) | 135-142 |

Number of pages | 8 |

Journal | Journal of Chromatography A |

Volume | 973 |

Issue number | 1-2 |

DOIs | |

Publication status | Published - Oct 11 2002 |

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### Keywords

- Aldehydes
- Enthalpy of solution
- Ketones
- Retention indices
- Temperature dependence

### ASJC Scopus subject areas

- Analytical Chemistry
- Biochemistry
- Organic Chemistry

### Cite this

*Journal of Chromatography A*,

*973*(1-2), 135-142. https://doi.org/10.1016/S0021-9673(02)01198-6