Quantitative NMR of quadrupolar nucleus as a novel analytical method: hydrolysis behaviour analysis of aluminum ion

Abstract

In this study, quantitative nuclear magnetic resonance (qNMR) spectroscopy of quadrupolar nuclei has been established. The complicated hydrolysis behavior of the Al ion, which causes fish poisoning and inhibits the growth of plants in environmental water, was clarified by Al qNMR spectroscopy. Highly accurate simultaneous multicomponent quantitative analysis of various hydrolyzed forms of the Al ion was achieved in a non-destructive manner. The calibration curve of the external standard aqueous Al(NO) solution showed excellent linearity over a very wide concentration range from 1 × 10 to 1 mol L (an increase in concentration of 10 000 times), with a simple experimental and analytical procedure. Furthermore, the weaknesses of the conventional Ferron assay and the advantages of Al qNMR spectroscopy were considered. The quantitative determination error for the free [Al(HO)] ion and the trinuclear complex, which has a high complexation rate, is higher in the Ferron assay than in the Al qNMR technique. The concentrations of four Al species were directly determined byAl qNMR, namely, free [Al(HO)], the trinuclear complex, Al(OH), and tridecameric hydrolyzed Al, which has a Keggin structure. The concentration of the tridecamer rapidly increased until 100 min after NaOH addition, and showed a local maximum after 1 week. In addition, the concentration of colloidal Al hydroxide, which cannot be detected by NMR spectroscopy, was determined by numerical analysis. This species was generated in the initial stage of reaction, and then the tridecamer formed very slowly.

Direct speciation methods to quantify catalytically active species of AlCl3in glucose isomerization

“…31 qNMR spectroscopy is non-destructive, quantitative, and uses a low-energy electromagnetic wave, causing an extremely small energy perturbation to the system. [32][33][34] In addition, the quantitative accuracy of NMR analysis has reached three signicant gures. [32][33][34] Following a similar approach to that of Maki et al, 32 we measured the concentration of Al 3+ by comparing the qNMR peak areas of experimental samples to an external standard, which consisted of 5 mM AlCl 3 and 100 mM HCl.…”

Quantification of Cathinone Analogues without Reference Standard Using 1H Quantitative NMR

“…The quantitative principle of 1 H qNMR spectroscopy is that the intensity of each signal in the spectrum (i.e., the integrated signal area) is directly proportional to the number of hydrogen atoms that generate the signal. The quantitative result of the seized sample was therefore calculated according to the following equation 21 :…”

Solvent molecule mobilities in propylene carbonate-based electrolyte solutions coexisting with fumed oxide nanoparticles

“…The values are defined as following equation; 1 H qNMR analysis was carried out using the integrated intensities of 1 H NMR signals due to PC molecules. 1 H qNMR is defined as following equation [33,34]; (4) where N is the concentration of the chemical species which give the NMR signal, Rg is the receiver gain in decibel unit of an NMR spectrometer (i.e., receiver gain), Ns is the number of FID scans, and I is the integrated intensity of the NMR signal. The subscripts "x" and "ref" indicate the sample solution and the external reference for NMR measurements, respectively.…”