Quantitative determination of carboxylate by infrared spectroscopy: application to humic acids

Acid Liquefaction of Potato (Solanum tuberosum) and Sweet Potato (Ipomoea batatas) Cultivars Peels – Pre-Screening of Antioxidant Activity/Total Phenolic and Sugar Contents

“…Such compounds are highly prone to migrate to the water extract, and more so, if carboxylic acids are present in the carboxylate form. The centered peak at 1353 cm -1 was assigned to a carboxylate group (Hadžija and Špoljar 1995). Moreover, in acidic mediums, the reactions between the hydroxyl groups and phenolic molecules could occur.…”

Structural environments of carboxyl groups in natural organic molecules from terrestrial systems. Part 1: Infrared spectroscopy

“…Salicylate was proposed in part based on chemical studies suggesting that phenolic OH and the carboxylate anion simultaneously participate in metal chelation, while alcoholic OH does not (Schnitzer and Skinner, 1965). Since then, salicylate has been a particularly popular choice as a general humic substance analogue (for example, see Yost et al, 1990;Stevenson, 1994;Hadzija and Spoljar, 1995;Celi et al, 1997;Kubicki et al, 1997;and Dupuy and Douay, 2001). Aromatic carboxyl groups have also been implicated in the RANDOM modeling studies of Murray and Linder (1983;1984;Linder and Murray, 1987), in which molecular structures are assembled as random assortments of functional groups within a mixed aromatic/aliphatic polymer matrix.…”

“…In this study, we used attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to probe the structural environment of carboxyl groups in NOM directly without any chemical treatment. Many examples exist in the literature in which infrared spectroscopy has been used as a probe to detect the presence and relative abundance of carboxyl groups in NOM, while some authors have suggested ways in which infrared spectroscopy, with proper calibration, can be used as a method for determining absolute carboxylic concentrations (Cabaniss, 1991;Hadzija and Spoljar, 1995). Though examples exist where infrared spectroscopy was used to infer carboxyl structural types after chemical treatment (e.g., cyclic anhydride formation (Wood et al, 1961;Wagner and Stevenson, 1965)), to the authors' knowledge, direct inference of carboxyl group structural environments in NOM has not been made from their infrared spectra.…”

Preparation and characterization of crosslinked poly(methylmethacrylate‐acrylic acid sodium salt)‐modified bone cement

“…Rufino and Monteiro show that the wavenumber of asymmetric stretching vibration for sodium salts of poly(methacrylic acid) is 1566 cm −1 18. Hadzija and Spoljar determined the infrared spectroscopy of COO − antisymmetric stretch vibration at 1580 cm –1 19. In this study, the wavenumbers of the asymmetrical and symmetrical stretching vibrations for carboxylate anion of crosslinked poly(MMA‐AAS‐AMA) were 1586 and 1407 cm −1 (Peaks 2 and 3 in Fig.…”