Work

Thermal Lens Vibrational Overtone Spectroscopy for Detection of Impurities in Liquid Alkanes

Year: 2026

Type: article

Abstract: In this investigation, the local mode model for C-H overtone transitions in hydrocarbons and the thermal lens (TL) technique are used to obtain vibrational overtone spectra and subsequent analysis of hydrocarbon impurities in liquid solutions. The experimental thermal lens design enables the detection of hydrocarbon solutes in trace amounts within a hydrocarbon solvent by exciting two distinct vibrational overtones. To exemplify the method, we present the thermal lens signal corresponding to the (Δυ = 6) overtone of benzene or naphthalene as impurities in solvents such as n-hexane or iso-octane. The lowest composition recorded for benzene in n-hexane was 0.005%, while for naphthalene in n-hexane it was 0.001%. Additionally, we explore more sensitive experiments where the (Δυ = 5) transition of the impurity is detected concurrently with the (Δυ = 6) transition of the solvent. This analytical method can also be adapted for use with saturated alcohols in solution contaminating hydrocarbon solvents.

Source: Chemosensors

DOI: 10.3390/chemosensors14020047

Authors: David Camejo, Miguel Rodriguez-Escalante, Parashu Nyaupane, Helena Diez-y-Riega, Carlos E. Manzanares

Institutions: Baylor University, Lone Star College

Language: English

Topic: Spectroscopy Techniques in Biomedical and Chemical Research

Subfield: Biophysics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: gold

Estimated APC paid: $2,413

Funder: Baylor University