Detection of 2,2′-Azobis(2-amidinopropane) Dihydrochloride in Polyvinylpyrrolidone by Capillary Electrophoresis with Field-Amplified Sample Injection

  • Chunli Lou
  • Mengmeng Zheng
  • Yao Xu
  • Yuting Shen
  • Jingwu KangEmail author
Short Communication


A sensitive method was developed for detecting 2,2′-azobis(2-amidinopropane) dihydrochloride in polyvinylpyrrolidone by capillary electrophoresis with indirect UV detection. The detection sensitivity was improved significantly using the field-amplified sample injection technique. The background electrolyte was composed of 25 mM imidazole-HCl solution (pH 4.0), in which imidazole acted as the cation probe for the indirect detection at UV 214 nm. Effects of the experimental parameters including pH, the concentration of imidazole as well as the sample injection time on sample preconcentration were investigated and optimized. Under the optimized conditions, baseline separation of 2,2′-azobis(2-amidinopropane) ion with other ions in the polyvinylpyrrolidone samples was achieved within 8 min. The RSD% for the repeatability of the migration time and the peak area were determined as 0.95% and 3.47%, respectively. The limit of detection (LOD, S/N = 3) and the limit of quantitation (LOQ, S/N = 10) were determined as 1.11 × 10−5 M and 2.77 × 10−5 M, respectively. The measured recovery at three concentration levels was in the range of 101–104%. This method was successfully applied to detect 2,2′-azobis(2-amidinopropane) in the commercial polyvinylpyrrolidone samples.


Capillary electrophoresis Field-amplified sample injection Polyvinylpyrrolidone 2,2′-Azobis(2-amidinopropane) dihydrochloride 



This work was financially supported by the National Natural Science Foundations of China (21775158, 21375140, 21175146) and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB20020200).

Compliance with Ethical Standards

Conflict of Interest

The authors have declared no conflict of interest.

Ethical Statement

This article does not contain any studies with human participants or animals performed by any of the authors.

Supplementary material

10337_2019_3765_MOESM1_ESM.docx (115 kb)
Supplementary material 1 This material is available free of charge via the Internet. (DOCX 114 kb)


  1. 1.
    Haaf F, Sanner A, Straub F (1985) Polymers of N-vinylpyrrolidone: synthesis, characterization and uses. Polym J 17:143CrossRefGoogle Scholar
  2. 2.
    Hiramoto K, Johkoh H, Sako K-I, Kikugawa K (1993) Dna breaking activity of the carbon-centered radical generated from 2,2′-azobis(2-amidinopropane) hydrochloride (AAPH). Free Radic Res Commun 19:323–332CrossRefGoogle Scholar
  3. 3.
    Werber J, Wang YJ, Milligan M, Li X, Ji JA (2011) Analysis of 2,2′-azobis (2-amidinopropane) dihydrochloride degradation and hydrolysis in aqueous solutions. J Pharm Sci 100:3307–3315CrossRefGoogle Scholar
  4. 4.
    Doble P, Haddad PR (1999) Indirect photometric detection of anions in capillary electrophoresis. J Chromatogr A 834:189–212CrossRefGoogle Scholar
  5. 5.
    Pacáková V, Štulı́k K, (1997) Capillary electrophoresis of inorganic anions and its comparison with ion chromatography. J Chromatogr A 789:169–180CrossRefGoogle Scholar
  6. 6.
    Weston A, Brown PR, Jandik P, Heckenberg AL, Jones WR (1992) Optimization of detection sensitivity in the analysis of inorganic cations by capillary ion electrophoresis using indirect photometric detection. J Chromatogr A 608:395–402CrossRefGoogle Scholar
  7. 7.
    Timerbaev AR, Buchberger W (1999) Prospects for detection and sensitivity enhancement of inorganic ions in capillary electrophoresis. J Chromatogr A 834:117–132CrossRefGoogle Scholar
  8. 8.
    Chien RL, Burgi DS (1992) Sample stacking of an extremely large injection volume in high-performance capillary electrophoresis. Anal Chem 64:1046–1050CrossRefGoogle Scholar
  9. 9.
    Chien R-L, Burgi DS (1991) Field amplified sample injection in high-performance capillary electrophoresis. J Chromatogr A 559:141–152CrossRefGoogle Scholar
  10. 10.
    Zhang C-X, Thormann W (1996) Head-column field-amplified sample stacking in binary system capillary electrophoresis: a robust approach providing over 1000-fold sensitivity enhancement. Anal Chem 68:2523–2532CrossRefGoogle Scholar
  11. 11.
    Kaniansky D, Marák J (1990) On-line coupling of capillary isotachophoresis with capillary zone electrophoresis. J Chromatogr A 498:191–204CrossRefGoogle Scholar
  12. 12.
    Britz-McKibbin P, Bebault GM, Chen DDY (2000) Velocity-difference induced focusing of nucleotides in capillary electrophoresis with a dynamic pH junction. Anal Chem 72:1023–1030CrossRefGoogle Scholar
  13. 13.
    Quirino J, Terabe S (1999) Sweeping of analyte zones in electrokinetic chromatography. Anal Chem 71:1638–1644CrossRefGoogle Scholar
  14. 14.
    Quirino J, Haddad P (2008) Online sample preconcentration in capillary electrophoresis using analyte focusing by micelle collapse. Anal Chem 80:6824–6829CrossRefGoogle Scholar
  15. 15.
    Ghiasvand A, Feng Z, Quirino J (2019) Enrichment and separation of cationic, neutral, and chiral analytes by micelle to cyclodextrin stacking-micellar electrokinetic chromatography. Anal Chem 91:1752–1757CrossRefGoogle Scholar
  16. 16.
    Simpson SL, Quirino JP, Terabe S (2008) On-line sample preconcentration in capillary electrophoresis: fundamentals and applications. J Chromatogr A 1184:504–541CrossRefGoogle Scholar
  17. 17.
    Zhang C-X, Meagher MM (2017) Sample stacking provides three orders of magnitude sensitivity enhancement in SDS capillary gel electrophoresis of adeno-associated virus capsid proteins. Anal Chem 89:3285–3292CrossRefGoogle Scholar
  18. 18.
    Quirino J, Terabe S (2000) Approaching a million-fold sensitivity increase in capillary electrophoresis with direct ultraviolet detection: cation-selective exhaustive injection and sweeping. Anal Chem 72:1023–1030CrossRefGoogle Scholar
  19. 19.
    Wang W-F, Yang J-L, Shi Y-P (2018) Quality evaluation of six bioactive constituents in goji berry based on capillary electrophoresis field amplified sample stacking. Electrophoresis 39:2117–2124CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Chunli Lou
    • 1
    • 2
    • 3
  • Mengmeng Zheng
    • 2
    • 3
  • Yao Xu
    • 2
    • 3
  • Yuting Shen
    • 2
    • 3
  • Jingwu Kang
    • 1
    • 2
    • 3
    Email author
  1. 1.School of Physical Science and TechnologyShanghaiTech UniversityShanghaiChina
  2. 2.State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
  3. 3.University of Chinese Academy of SciencesBeijingChina

Personalised recommendations