Quantifying crystal form content in physical mixtures of (±)-tartaric acid and (+)-tartaric acid using near infrared reflectance spectroscopy

Abstract

The objective of this study was to use diffuse reflectance near infrared spectroscopy (NIRS) to determine racemic compound content in physical mixtures composed primarily of the enantiomorph and to assess the error, instrument reproducibility and limits of detection (LOD) and quantification (LOQ) of the method. Physical mixtures ranging from 0 to 25% (±)−tartaric acid in (+)−tartaric acid were prepared and spectra of the powder samples contained in glass vials were obtained using a Foss NIRSystems Model 5000 monochrometer equipped with a Rapid Content Analyzer scanning from 1100 to 2500 nm. A calibration curve was constructed by plotting (±)−tartaric acid weight percent against the 2 nd derivative values of log (1/R) vs λ at a single wavelength, normalized with a denominator wavelength (1480 nm/1280 nm). Excellent linearity was observed (R 2 =0.9999). The standard error of calibration (SEC) was 0.07 and the standard error of prediction (SEP) for the validation set was 0.11. Instrument and method errors for samples in the 2% composition range ((±) −tartaric acid in (+)−tartaric acid) were less than 1% RSD and 3% RSD, respectively. The practical LOD and LOQ were 0.1% and 0.5%, respectively, and comparable to the calculated LOD and LOQ. These studies show that NIRS can be used as a rapid and sensitive quantitative method for determining racemate content in the presence of the enatiomerically pure crystal in the solid-state.

Characterization and recovery of tartaric acid from wastes of wine and grape juice industries

“…Luner et al [10] investigated that the effect of grinding on the crystal structure of natural tartaric acid. They concluded that there was no major difference between the crystallinity of powder and natural tartaric acid sample and also they observed the natural pattern of tartaric acid.…”

A Tamarind Local Variety from Garoua, Cameroon: Physicochemical Characterization, Fruit Pulp Fermentation and Extraction of Tartaric Acid from the Fruit Pulp Winery Waste

“…The crystallinity of the sample under investigation was comparable with that of a standard XRD profile, although the sample under investigation was more powdery. Literature reports on the effect of grinding on the crystal structure of natural Tartaric acid concluded that particle size of Tartaric acid does not affect the crystallinity of the sample [30] . The XRD profiles observed in literature for the pattern of Tartaric acid were similar to those in this study.…”

Green Multi-Platform Solution for the Quantification of Levodopa Enantiomeric Excess in Solid-State Mixtures for Pharmacological Formulations

“…Despite the number of advantages that a green and fast procedure for the enantiomeric excess quantification has, in the literature, the possibility of using NIR or MIR for the quantification of enantiomers in mixture has been described only for a reduced number of compounds of pharmacological interest. In particular, this has been accomplished by means of MIR for mandelic acid and ketoprofen [ 14 ], and by NIR for ibuprofen, epinephrine [ 15 ], and tartaric acid [ 16 ]. In the former case, mandelic acid and ketoprofen were quantified by means of a chemometric regression strategy based on partial least squares (PLS) [ 17 , 18 ] and by exploiting a multivariate curve resolution (MCR).…”