Use of ultrasound in gradient elution of Polycyclic Aromatic Hydrocarbon mixtures by HPLC

Stainless steel (SS) and polyether ether ketone (PEEK) C18 columns were submerged in an ultrasonic bath operating at a frequency of 36 kHz to separate a mixture of polycyclic aromatic hydrocarbons (PAHs), including naphthalene, anthracene, and pyrene, using high-performance liquid chromatography (HPLC) with ultrasound radiation applied at intensities ranging from 0% to 100% of the 900 W output power. Sono-gradient elution was used to ultrasonically irradiate the mixture at specific points during the elution to improve the separation factor by increasing the interval between the target peaks and shorten the analysis time by reducing the retention time of the desired PAH peak.