Magnetic Ionic Liquids as Solvents for RNA Extraction and Preservation

Ribonucleic acid (RNA) is particularly sensitive to enzymatic degradation by endonucleases prior to sample analysis. In-field preservation has been a challenge for RNA sample preparation. Very recently, hydrophobic magnetic ionic liquids (MIL) have shown significant promise in the area of RNA extraction. In this study, MILs were synthesized and employed as solvents for the extraction and preservation of RNA in aqueous solution. RNA samples obtained from yeast cells were extracted and preserved by the trihexyl(tetradecyl) phosphonium tris(hexafluoroacetylaceto)cobaltate(II) ([P₆₆₆₁₄ ⁺][Co(hfacac)₃ ^-]) and trihexyl(tetradecyl) phosphonium tris(phenyltrifluoroacetylaceto)cobaltate(II) ([P₆₆₆₁₄ ⁺][Co(Phtfacac)₃ ^-]) MIL with a dispersion of the supporting media, polypropylene glycol, at room temperature for up to a 7 and 15 day period, respectively. High-quality RNA treated with ribonuclease A (RNase A) was recovered from the tetra(1-octylimidazole)cobaltate(II) di(l-glutamate) ([Co(OIM)₄ ²⁺][Glu^-]₂) and tetra(1-octylimidazole)cobaltate(II) di(l-aspartate) ([Co(OIM)₄ ²⁺][Asp^-]₂) MILs after a 24 h period at room temperature. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and agarose gel electrophoresis were used to determine the effect of RNA preservation. Furthermore, the preservation mechanism was investigated by exploring the partitioning of RNase A into the MIL using high-performance liquid chromatography.