Lipid perturbations in human body are known to be related to various types of diseases, ranging from common adult diseases to more severe forms of cancer. Therefore, it is important to analyze and interpret lipid profiles and their changes systematically. However, since lipids are easily degraded at room temperature, if the sample is exposed to room temperature for a long time (due to mistakes during transportation, etc.), the lipids in biological sample can be destroyed. To prevent such a deterioration, the use of organic solvent for lipid sample storage would be efficient. Among the human samples used for lipidomics, solvent optimization of the saliva sample was first performed.

Prior to optimizing the storage solvent of the saliva sample, the extraction time of the saliva sample was optimized first. Saliva samples were divided by extraction period (1h, 2h, 4h, 8h), and qualitative, quantitative analysis were performed using nano flow ultrahigh pressure liquid chromatography-electrospray ionization-tandem mass spectrometry (nUHPLC-ESI-MS/MS). From statistical comparison of MS results using Intraclass Correlation Coefficient (ICC),  extraction period of saliva sample is selected with 1 hour. Saliva samples were treated with different solvent conditions and left at room temperature for different time periods (0 day, 1 day, 2 days, and 4 days) for the selection of the optimum solvent condition.