Abstract

The simultaneous determination of amino acids in solution is important for food and nutrient industries. This study investigated the feasibility of potentiometric titration with synergy interval Partial Least Square (siPLS) for the simultaneous determination of glycine, glutamic acid and phenylalanine in aqueous solution. The methods used were compared with the traditional Partial Least Square (PLS) that based on full pH range. The performance was evaluated by the Root Mean Square Error of Cross-Validation (RMSECV), the Root Mean Square Error of Prediction (RMSEP) and the correlation coefficient (R). By optimizing the pH region with siPLS, a good linear model was produced for the calibration set with correlation coefficient R of 0.9947, 0.9956 and 0.9913 for glycine, glutamic acid and phenylalanine, respectively. A single set of synergy mixtures was tested independently and good results were obtained. The results show that the siPLS method can locate the informative region by using a graphically-oriented interface which is more easily to use and interpret. The study proves the feasibility of potential titration with chemometrics in the simultaneous determination of amino acid mixtures without preliminary separation.

Keywords:

Amino acids, chemometrics, partial least square, potentiometric titration,

References

1. Aktas, A.H. and S. Yasar, 2004. Potentiometric titration of some hydroxylated benzoic acids and cinnamic acids by artificial neural network calibration. Acta Chim. Slov., 51(2): 273-282.
   
2. Assefa, M.D., A.K. Chaubey, A. Taddess and A.Y. Hibstie, 2013. Relative determination of micronutrients of different species of Teff (Eragrestis) seeds of Ethiopia origin by calibration free laser induced breakdown spectroscopy techniques. Adv. J. Food Sci. Technol., 5(3): 332-338.
   CrossRef    
3. Cai, J.R., Q.S. Chen, X.M. Wan and J.W. Zhao, 2011. Determination of Total Volatile Basic Nitrogen (TVB-N) content and Warner-Bratzler Shear Force (WBSF) in pork using Fourier transform near infrared (FT-NIR) spectroscopy. Food Chem., 126(3): 1354-1360.
   CrossRef    
4. Cerdán, M., A. Sánchez-Sánchez, J.D. Jordá, M. Juárez and J. Sánchez-Andreu, 2013. Effect of commercial amino acids on iron nutrition of tomato plants grown under lime-induced iron deficiency. J. Plant Nutr. Soil Sc., 176(6): 859-866.
   
5. Chen, H.P., L. Chen, Y.M. Wei and Y.L. Zheng, 2005. Simultaneous determination of amino acids in wheat by reversed phase high performance liquid chromatography with precolumn derivatization. Chin. J. Anal. Chem., 33(12): 1689-1692.
   
6. Chen, Q.S., J. Ding, J.R. Cai and J.W. Zhao, 2012a. Rapid measurement of Total Acid Content (TAC) in vinegar using near infrared spectroscopy based on efficient variables selection algorithm and nonlinear regression tools. Food Chem., 135(2): 590-595.
   CrossRef    PMid:22868133    
7. Chen, Q.S., J. Ding, J.R. Cai, Z.B. Sun and J.W. Zhao, 2012b. Simultaneous measurement of total acid content and soluble salt-free solids content in Chinese vinegar using near-infrared spectroscopy. J. Food Sci., 77(2): 222-227.
   CrossRef    PMid:22250960    
8. Christensen, J., L. Nørgaard, R. Bro and S.B. Engelsen, 2006. Multivariate auto fluorescence of intact food systems. Chem. Rev., 106(6): 1979-1994.
   CrossRef    PMid:16771440    
9. Du, Y.P., Y.Z. Liang, J.H. Jiang, R.J. Berry and Y. Ozaki, 2004. Spectral regions selection to improve prediction ability of PLS models by changeable size moving window partial least squares and searching combination moving window partial least squares. Anal. Chim. Acta, 501(2): 183-191.
   CrossRef    
10. Fang, S., M.Q. Zhu and C.H. He, 2009. Moving window as a variable selection method in potentiometric titration multivariate calibration and its application to the simultaneous determination of ions in Raschig synthesis mixtures. J. Chemometr., 23(3): 117-123.
    CrossRef    
11. Ferrão, M.F., M.S. Viera, R.E.P. Pazos, D. Fachini, A.E. Gerbase and L. Marder, 2011. Simultaneous determination of quality parameters of biodiesel/diesel blends using HATR-FTIR spectra and PLS, iPLS or siPLS regressions. Fuel, 90(2): 701-706.
    CrossRef    
12. Ghorbani, R., J. Ghasemi and B. Abdollahi, 2006. Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares. J. Hazard. Mater., 131(1-3): 13-18.
    CrossRef    PMid:16236436    
13. Goicoechea, H.C. and A.C. Olivieri, 2003. A new family of genetic algorithms for wavelength interval selection in multivariate analytical spectroscopy. J. Chemometr., 17(6): 338-345.
    CrossRef    
14. Hemmateenejad, B. and S. Karimi, 2011. Construction of stable multivariate calibration models using unsupervised segmented principal component regression. J. Chemometr., 25(4): 139-150.
    CrossRef    
15. Hemmateenejad, B., S. Karimi and N. Mobaraki, 2013. Clustering of variables in regression analysis: A comparative study between different algorithms. J. Chemometr., 27(10): 306-317.
    CrossRef    
16. Henchoz, Y., J. Schappler, L. Geiser, J. Prat, P.A. Carrupt and J.L. Veuthey, 2007. Rapid determination of pKa values of 20 amino acids by CZE with UV and capacitively coupled contactless conductivity detections. Anal. Bioanal. Chem., 389(6): 1869-1878.
    CrossRef    PMid:17874082    
17. Jiang, J.H., R.J. Berry, H.W. Siesler and Y. Ozaki, 2002. Wavelength interval selection in multicomponent spectral analysis by moving window partial least-squares regression with applications to mid-infrared and near infrared spectroscopic data. Anal. Chem., 74(14): 3555-3565.
    CrossRef    PMid:12139068    
18. Leardi, R. and L. Nørgaard, 2004. Sequential application of backward interval PLS and genetic algorithms for the selection of relevant spectral regions. J. Chemometr., 18(11): 486-497.
    CrossRef    
19. Liebster, J., K. Kopoldová and M. Dobiáýová, 1961. A simplified method for separating amino-acid mixtures from protein hydrolysates on one ion-exchange column during preparation. Nature, 191: 1198.
    CrossRef    PMid:13762028    
20. Lindberg, W. and B. Kowalski, 1988. Evaluation of potentiometric acid-base titrations by partial-least-squares calibration. Anal. Chim. Acta, 206: 125-135.
    CrossRef    
21. Li, W., L. Lin and G. Li, 2014. Wavelength selection method based on test analysis of variance: application to oximetry. Anal. Method., 6: 1082-1089.
    CrossRef    
22. Michalowski, T., M. Toporek and M. Rymanowski, 2005. Overview on the Gran and other linearisation methods applied in titrimetric analysis. Talanta, 65: 1241-1253.
    CrossRef    PMid:18969938    
23. Mohabbat, T. and B. Drew, 2008. Simultaneous determination of 33 amino acids and dipeptides in spent cell culture media by gas chromatography-flame ionization detection following liquid and solid phase extraction. J. Chromatogr. B, 862(1-2): 86-92.
    CrossRef    PMid:18069078    
24. Moore, S. and W.H. Stein, 1949. Chromatography of amino acids on starch columns. Solvent mixtures for the fractionation of protein hydrolysates. J. Biol. Chem., 178(1): 53-77.
    PMid:18112090    
25. Mudiam, M.K.R., C. Ratnasekhar, R. Jain, P.N. Saxena, A. Chauhan and R.C. Murthy, 2012. Rapid and simultaneous determination of twenty amino acids in complex biological and food samples by solid-phase microextraction and gas chromatography-mass spectrometry with the aid of experimental design after ethyl chloroformate derivatization. J. Chromatogr. B, 907: 56-64.
    CrossRef    PMid:22998980    
26. Munck, L., L. Nørgaard, S.B. Engelsen, R. Bro and C.A. Andersson, 1998. Chemometrics in food science-a demonstration of the feasibility of a highly exploratory, inductive evaluation strategy of fundamental scientific significance. Chemometr. Intell. Lab., 44(1-2): 31-60.
    CrossRef    
27. Ni, Y.N., 1998. Simultaneous determination of mixtures of acids by potentiometric titration. Anal. Chim. Acta, 367(1-3): 145-152.
    CrossRef    
28. Ni, Y.N. and A.G. Wu, 1999. Simultaneous determination of halide and thiocyanate ions by potentiometric precipitation titration and multivariate calibration. Anal. Chim. Acta, 390(1-3): 117-123.
    CrossRef    
29. Ni, Y.N. and S. Kokot, 2008. Does chemometrics enhance the performance of electroanalysis? Anal. Chim. Acta, 626: 130-146.
    CrossRef    PMid:18790114    
30. Ni, Y.N. and Y.L. Wu, 1997. Simultaneous determination of mixed metal ions by complexometric titration and multivariate calibration. Anal. Chim. Acta, 354: 233-240.
    CrossRef    
31. Ni, Y.N. and Z.H. Peng, 1995. Determination of mixed metal ions by complex metric titration and nonlinear partial least squares calibration. Anal. Chim. Acta, 304: 217-222.
    CrossRef    
32. Norgaard, L., A. Saudland, J. Wagner, J.P. Nielsen, L. Munck and S.B. Engelsen, 2000. Interval Partial Least Squares Regression (iPLS): A comparative chemometric study with an example from near-infrared spectroscopy. Appl. Spectrosc., 54(3): 413-419.
    CrossRef    
33. Ohtani, M., M. Sugita and K. Maruyama, 2006. Amino acid mixture improves training efficiency in athletes. J. Nutr., 136(2): 538-543.
    CrossRef    
34. Ouyang, Q., J.W. Zhao, Q.S. Chen, H. Lin and Z.B. Sun, 2012. Rapid measurement of antioxidant activity in dark soy sauce by NIR spectroscopy combined with spectral intervals selection and nonlinear regression tools. Anal. Method., 4(4): 940-946.
    CrossRef    
35. Redruello, B., V. Ladero, I. Cuesta, J.R. Álvarez-Buylla, M.C. Martín, M. Fernández and M.A. Alvarez, 2013. A fast, reliable, ultra high performance liquid chromatography method for the simultaneous determination of amino acids, biogenic amines and ammonium ions in cheese, using diethyl ethoxymethylenemalonate as a derivatising agent. Food Chem., 139(1-4): 1029-1035.
    CrossRef    PMid:23561206    
36. Savitzky, A. and M.J.E. Golay, 1964. Smoothing and differentiation of data by simplified least squares procedures. Anal. Chem., 36(8): 1627-1639.
    CrossRef    
37. Shamsipur, M., B. Hemmateenejad and M. Akhond, 2002. Multicomponent acid base titration by principal component-artificial neural network calibration. Anal. Chim. Acta, 461(1): 147-153.
    CrossRef    
38. Smith, J.T., 1997. Developments in amino acid analysis using capillary electrophoresis. Electrophoresis, 18(12-13): 2377-2392.
    CrossRef    PMid:9456052    
39. Song, X.H., J. Xu and R.Q. Yu, 1993. Artificial neural networks applied to potentiometric titration of multi-component polybasic acid mixtures. Microchim. Acta, 111(4-6): 199-206.
    CrossRef    
40. Wakayama, M., N. Aoki, H. Sasaki and R. Ohsugi, 2010. Simultaneous analysis of amino acids and carboxylic acids by capillary electrophoresis-mass spectrometry using an acidic electrolyte and uncoated fused-silica capillary. Anal. Chem., 82(24): 9967-9976.
    CrossRef    PMid:21080676    
41. Wei, X., N. Xu, D. Wu and Y. He, 2014. Determination of branched-amino acid content in fermented cordyceps sinensis mycelium by using FT-NIR Spectroscopy technique. Food Bioprocess Tech., 7(1): 184-190.
    CrossRef    
42. Xu, L., Z.H. Ye, H.F. Cui, X.P. Yu, C.B. Cai and H.W. Yang, 2012. Calibrating the shelf-life of Chinese flavored dry Tofu by FTIR spectroscopy and Chemometrics: Effects of data preprocessing and nonlinear transformation on multivariate calibration accuracy. Food Anal. Method., 5(6): 1328-1334.
    CrossRef    
43. Zhang, Y., J. Sun, X.T. Yu and T.H. Li, 2005. Simultaneous determination of iron and aluminum with constant potential complexometric titration under non-equilibrium state. Chin. J. Anal. Chem., 33(12): 1764-1766.
    
44. Zhao, M., Y. Ma, L.L. Dai, D.L. Zhang, J.H. Li, W.X. Yuan, Y.L. Li and H.J. Zhou, 2013. A high-performance liquid chromatographic method for simultaneous determination of 21 free amino acids in tea. Food Anal. Method., 6(1): 69-75.
    CrossRef    

Competing interests

The authors have no competing interests.

Open Access Policy

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Copyright

The authors have no competing interests.