An exploratory study to evaluate the potential of nanohydroxyapatite as a powerful sorbent for efficient extraction of volatile organic metabolites, potential biomarkers of cancer

Abstract

Developing early-stage diagnostic methods which are specific, highly sensitive and non-invasive for cancer has received much attention. In this paper, nanohydroxyapatite (NHA) was for the first time used as a sorbent to extract volatile organic metabolites (VOMs) which are considered as potential biomarkers of cancer, such as hexanal, heptanal, decanal, benzaldehyde, 4-heptanone, phenol, undecane, and 5-methyl-2-furfural. The extraction process was performed by simply dispersing nanohydroxyapatite into working solution containing targeted VOMs and then eluting the centrifuged sorbent with an organic solvent. Batch techniques were performed to optimize the experimental variables affecting the extraction of targeted VOMs such as the sorbent amount, adsorption time, elution time and types of elution solvent. The eluent was collected, concentrated and analyzed by gas chromatography-mass spectrometry (GC-qMS). Under optimized conditions, the results obtained demonstrated a good linearity (r² ≥ 0.993), over the linear dynamic range, for all urinary volatile metabolites investigated. The proposed strategy provided limits of detection (LODs) ranging from 9.8 ng L⁻¹ to 69.5 ng L⁻¹ and limits of quantification (LOQs) from 32.5 ng L⁻¹ to 231.6 ng L⁻¹. The method also afforded satisfactory results in terms of the matrix effect (72.8–96.1%) and recoveries (accuracy) higher than 70% for most of the studied VOMs. The intra-day and inter-day precision was lower than 3% and 13%, respectively. The established method has been successfully applied to the determination of the target urinary VOMs, from cancer patients, described as potential cancer biomarkers.