Quantification analysis of polymeric Al species in solutions with electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS)

Abstract

With the help of Ferron colorimetric method and 27Al NMR spectroscopy, quantification analysis method of electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) on Al speciation was developed and thus Al species in polymeric Al solutions were quantitatively analyzed. Based on the speciation results of mononuclear Al solution and purified Al 13 solution, Al species obtained with ESI-TOF-MS in polymeric Al solutions were classified into three categories as low polymers (i.e., Al 1–Al 10), mid polymers (i.e., Al 13–Al 20), and high polymers (i.e., Al 21–Al 31). Among these polymers, only a certain number of Al species have relative high content and constitute the dominant component of polymeric Al solutions. The quantification analysis results of ESI-TOF-MS agree well with those obtained by the other two traditional methods, which proves the feasibility of the novel method on Al species analysis. Additionally, ESI-TOF-MS can provide more information on Al speciation than 27Al NMR spectroscopy and Ferron colorimetric method, and the quantification analysis results can clearly explain the difference between the two traditional methods.