Abstract
Purity evaluation of amino acids using nuclear magnetic resonance spectroscopy is reported. Three amino acids (aspartic acid, valine, and arginine) and certified reference materials (CRMs), such as acidic, neutral, and basic amino acids, as well as a low pure sample of valine were used as the analytes. DCl solution, D2O, and NaOD solution were used as the preparation solvents. The quantitative values were obtained from all observed signals and compared with the certified values of the CRMs. When an amino acid was dissolved in water, a strong HOD signal due to proton exchange was observed. When the signal adjoining the HOD signal was considered in the evaluation, the accurate quantitative value could not be obtained. Therefore, under optimized conditions, the analyte signals separated from the HOD signal were chosen for purity determination of amino acids. As a result, the quantitative values were in agreement with the certified values of CRMs. An expanded uncertainty was estimated to be approximately 0.002 kg kg−1. We also discuss the effect of impurities on purity determination based on all signals and conclude that agreement of quantitative values determined from different signals in a molecule is a good indication of the accuracy of the results.
References
Bharti SK, Roy R (2012) Quantitative 1H NMR spectroscopy. Trends Anal Chem 35:5–26
Saito T, Nakaie S, Kinoshita M, Ihara T, Kinugasa S, Nomura A, Maeda T (2004) Practical guide for accurate quantitative solution state NMR analysis. Metrologia 41:213–218
Saito T, Ihara T, Sato H, Jancke H, Kinugasa S (2003) International comparison on the determination of an ethanol aqueous solution by 1H nuclear magnetic resonance. Bunseki Kagaku 52:1029–1036
Saito T, Ihara T, Miura T, Yamada Y, Chiba K (2011) Efficient production of reference materials of hazardous organics using smart calibration by nuclear magnetic resonance. Accred Qual Assur 16:421–428
Saito T, Ihara T, Koike M, Kinugasa S, Fujimine Y, Nose K, Hirai T (2009) A new traceability scheme for the development of international system-traceable persistent organic pollutant reference materials by quantitative nuclear magnetic resonance. Accred Qual Assur 14:79–86
Al-Deen TS, Hibbert DB, Hook JM, Wells RJ (2004) An uncertainty budget for the determination of the purity of glyphosate by quantitative nuclear magnetic resonance (QNMR) spectroscopy. Accred Qual Assur 9:55–63
Schoenberger T (2012) Determination of standard sample purity using the high-precision 1H-NMR process. Anal Bioanal Chem 403:247–254
Wells RJ, Cheung J, Hook JM (2004) Dimethylsulfone as a universal standard for analysis of organics by QNMR. Accred Qual Assur 9:450–456
Michael W, Christine H, Alex R, Robert S, Jurg W (2013) Using high-performance quantitative NMR(HP-qNMR) for certifying traceable and highly accurate purity values of organic reference materials with uncertainties < 0.1%. Accred Qual Assur 18(2):91–98
Beyer T, Schollmayer C, Holzgrabe U (2010) The role of solvents in the signal separation for quantitative 1H NMR spectroscopy. J Pharm Biomed Anal 52:51–58
Kinumi T, Goto M, Eyama S, Kato M, Kasama T, Takatsu A (2012) Development of SI-traceable C-peptide certified reference material NMIJ CRM 6901-a using isotope-dilution mass spectroscopy-based amino acid analysis. Anal Bioanal Chem 404:12–21
Burkitt IW, Pritchard C, Arsene C, Henrion A, Bunk D, O’Connor G (2008) Toward System International d’Unite-traceable protein quantification: from amino acids to proteins. Anal Biochem 376:242–251
Gautier AE, Roberti JM, Gettar TR, Rebagliati JR, Batistoni AD (2007) Assessment of chemical purity of 10B-enriched p-boronophenylalanine by high-performance liquid chromatography coupled on-line with inductively coupled plasma optical emission spectrometry. Anal Bioanal Chem 388:499–503
Takaya T, Kishida Y, Sakakibara S (1981) Determination of the optical purity of amino acids by high-performance liquid chromatography. J Chromatogr 215:279–287
Coggins RJ, Benoiton LN (1970) Determination of N-methylamino acids and their optical purity with an amino acid analyzer. J Chromatogr 52:251–256
Hardy JM (1974) Radiochemical determination of the optical purity of l-amino acid. Anal Biochem 57:529–533
Bolinder EA (1970) Purity of amino acid. Anal Biochem 35:212–226
Dunn SM, Murphy AE (1960) Chromatographic purity of amino acids: arginine. Anal Chem 32:461–463
Dunn SM, Murphy AE (1961) Chromatographic purity of amino acids: alanine, aspartic acid, cystine, histidine, hydroxyproline and proline. Anal Chem 33:997–998
Yamazaki T, Eyama S, Takatsu A (2012) Accurate purity analysis of l-lysine hydrochloride by using neutralization titration and uncertainty evaluation. Bunseki Kagaku 61:959–962
Holzgrabe U, Nap JA, Beyer T, Almeling S (2010) Alternatives to amino acid analysis for the purity control of pharmaceutical grade l-alanine. J Sep Sci 33:2402–2410
Yamazaki T, Saito T, Miura T, Ihara T (2012) Investigation of analysis conditions for accurate quantitative NMR analysis. Bunseki Kagaku 61:963–967
Shao G, Kautz R, Peng S, Cui G, Giese WR (2007) Calibration by NMR for quantitative analysis: p-toluenesulfonic acid as a reference substance. J Chromatogr A 1138:305–308
Malz F, Jancke H (2006) Purity assessment problem in quantitative NMR-impurity resonance overlaps with monitor signal multiplets from stereoisomers. Anal Bioanal Chem 385:760–765
Malz F, Jancke H (2005) Validation of quantitative NMR. J Pharmaceut Biomed 38:813–823
Wells RJ, Hook JM, Al-deen TS, Hibbert DB (2002) Quantitative nuclear magnetic resonance (QNMR) spectroscopy for assessing the purity of technical grade agrochemicals: 2,4-dichloropropionate acid (2,4-D) and sodium 2,2-dichloropropionate (dalapon sodium). J Agric Food Chem 50:3366–3374
Liu YS, Hu QC (2007) A comparative uncertainty study of the calibration of macrolide antibiotic reference standards using quantitative nuclear magnetic resonance and mass balance methods. Anal Chem Acta 602:114–121
Al-Deen TS, Hibbert DB, Hook JM, Wells RJ (2002) Quantitative nuclear magnetic resonance spectrometry. Purity of phosphorus-based agrochemicals glyphosate (N-(phosphonomethyl) O-ethyl S-propyl phosphorothioate) measured by 1H and 31P QNMR spectrometry. Anal Chem Acta 474:125–135
Claridge WDT, Davies GS, Polywka CEM, Roberts MP, Russell JA, Savory DE, Smith DA (2008) Pure by NMR? Org Lett 10:5433–5436
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Yamazaki, T., Takatsu, A. Quantitative NMR spectroscopy for accurate purity determination of amino acids, and uncertainty evaluation for different signals. Accred Qual Assur 19, 275–282 (2014). https://doi.org/10.1007/s00769-014-1067-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00769-014-1067-2