The use of acetone as a substitute for acetonitrile in analysis of peptides by liquid chromatography/electrospray ionization mass spectrometry

Abstract

The recent worldwide shortage of acetonitrile has prompted interest in alternative solvents for liquid chromatography/mass spectrometry (LC/MS). In this work, acetone was substituted for acetonitrile in the separation of a peptide mixture by reversed-phase high-performance liquid chromatography (RP-HPLC) and in the positive electrospray ionization mass spectrometry (ESI-MS) of individual peptides. On both C12 and C18 stationary phases, the substitution of acetone for acetonitrile as the organic component of the mobile phase did not alter the gradient elution order of a five-peptide retention standard, but did increase peak width, shorten retention times, and increase peak tailing. Positive ESI mass spectra were obtained for angiotensin I, bradykinin, [Leu(5)]-enkephalin, and somatostatin 14 dissolved in both acetonitrile/water/formic acid (25%/75%/0.1%) and acetone/water/formic acid (25%/75%/0.1%). Under optimized ESI-MS conditions, the mass spectral response of [Leu(5)]-enkephalin was increased two-fold when the solvent contained acetone. The substitution of acetone for acetonitrile resulted in only slight changes in the responses of the remaining peptides. A higher capillary voltage was required for optimum response when acetone was used. Compared with acetonitrile/water/formic acid (50/50/0.1%), more interfering species below m/z = 140 were found in the ESI-MS spectra of acetone/water/formic acid (50/50/0.1%).

Ultra-high-performance liquid chromatography-tandem mass spectrometry for the analysis of free and conjugated natural estrogens in cow milk without deconjugation

“…Acetone is a totally water-miscible solvent, and in contrast to UV detection, it is compatible with ESI; however, it has been proposed as an alternative to acetonitrile only for peptide separation during shortage of acetonitrile [29,30]. The polarity of acetone is lower than that of acetonitrile, and they also differ in basicity; therefore, a different selectivity toward acidic compounds might be expected.…”

Systematic evaluation of acetone and acetonitrile for use in hydrophilic interaction liquid chromatography coupled with electrospray ionization mass spectrometry of basic small molecules

“…At high pH using acetone, the overall s/n values were much lower and suppression of the responses obtained for the strongly basic solutes was impaired dramatically compared with those determined using the same solvent under acidic conditions. This can perhaps be related to the reactivity of acetone which exists as an enolate in aqueous basic conditions which can then result in the formation of analyte adducts and or diacetone, triacetone and higher condensation products, as observed by Keppel et al [15] and Fountain et al [17] It is also known that in solution chemistry tertiary amines do not react with carbonyl groups suggesting that only weakly dissociative analyte-solvent interactions are taking place. Figure 2 shows the presence of high intensity diacetone and triacetone condensation products in the extracted ion spectra from an injection of cytosine.…”

Acetone as a greener alternative to acetonitrile in liquid chromatographic fingerprinting

“…Acetone could be an alternative to replace acetonitrile in many RPHPLC applications since both solvents share similar physical and chemical characteristics, e.g. they are fully miscible with water, hydrogen bond acceptor solvents and present some similar solvatochromic properties , and similar viscosities . Such replacement would fit principles number 11 and 12 of GCA .…”

“…Such replacement would fit principles number 11 and 12 of GCA . The main drawback of acetone compared to acetonitrile is that acetone's UV cut‐off extends out to 330 nm restricting its usage with UV absorbance‐based detectors, the most popular detectors in LC, to a narrow range of wavelengths . Nevertheless, the fast popularization of MS‐based detectors in LC and the new generation of aerosol‐based LC detectors open new opportunities for the usage of acetone instead of acetonitrile.…”

“…Nevertheless, the fast popularization of MS‐based detectors in LC and the new generation of aerosol‐based LC detectors open new opportunities for the usage of acetone instead of acetonitrile. There are some reports on satisfactory replacement of acetonitrile with acetone in RPLC employing mass spectrometer detectors in the analysis of peptides . Recently, Hutchinson et al.…”