A novel and simple method for petroleum emulsion breaking and desalting is described and applied to crude oil. Such complex samples consist of stable water oil emulsions. The oil phase is comprised of petroleum whereas the aqueous. phase is composed of brine, including seawater, with varying salt content. Herein, crude oil dewatering was performed by applying a small aliquot of sample to a supported-liquid extraction cartridge. Multiphasic equilibration allowed the aqueous phase to adsorb onto the surface of porous diatomaceous earth (e.g., Celite). Organic solvents such as n-heptane, methylene chloride, and toluene easily desorbed the remaining oil phase. Potentiometric Karl Fisher titration and conductivity analysis confirmed near exhaustive (>98%) water and salt removal alongside particulate matter. This phenomenon was strikingly observed in both mild and harsh salt content conditions with concentrations ranging from zero to 200 000 ppm; the latter is found in Brazilian presalt crude oil samples. Quantitative petroleum recoveries (>98% of maltenes and >82% of asphaltenes), were also observed. Original composition of maltenes, including three important biomarker classes such as C-10 demethylated terpanes, tri, tetra-, and pentacyclic terpanes, and alpha alpha alpha-steranes were preserved. Minor asphaltene adsorption (<18%), led to significant alterations of polar asphaltenes. These data were ascertained by gravimetty, multidimensional gas chromatography, sod spectroscopy-based measurements, including nuclear magnetic resonance and Mass spectrometry experiments. Lastly, the deployed method was successfully applied to online crude oil dewatering and desalting, alongside saturate, aromatic, resin, and asphaltene heavy oil analysis. Results portrayed herein are fundamental in the development of powerful point-of-use technologies for petrochemistry field.