PMID- 35243839
OWN - NLM
STAT- MEDLINE
DCOM- 20220307
LR  - 20220915
IS  - 1872-2059 (Electronic)
IS  - 1000-8713 (Print)
IS  - 1000-8713 (Linking)
VI  - 40
IP  - 3
DP  - 2022 Mar 8
TI  - [Field-amplified sample injection and graphene quantum dot dual preconcentration 
      in the analysis of melamine and dicyandiamide by capillary electrophoresis].
PG  - 289-295
LID - 10.3724/SP.J.1123.2021.08017 [doi]
AB  - Sulfur-doped graphene quantum dots (S-GQDs) were prepared by the pyrolysis of 
      citric acid and mercaptopropionic acid. Compared with graphene quantum dots 
      (GQDs), the S-GQDs have improved surface state and chemical reactivity, and thus, 
      exhibited stronger interaction with cations. Based on its excellent affinity for 
      cations, a dual preconcentration technique combining field-amplified sample 
      injection (FASI) and S-GQDs as multianalyte carriers was developed for the 
      determination of melamine and dicyandiamide by capillary electrophoresis (CE). 
      During the FASI process, a large quantity of analytes was introduced into the 
      capillary and accumulated at the capillary inlet. Concurrently, the S-GQDs 
      migrated to the anode and captured the analytes on its surface at the boundary of 
      the sample and buffer solution. The use of S-GQDs allows the capture of abundant 
      analytes, which can amplify the detection signal. This new protocol was evaluated 
      by the quantitative determination of melamine and dicyandiamide in metformin 
      hydrochloride preparations. The effect of volume fraction of the S-GQDs in the 
      buffer solution, the composition and pH of the buffer, and the sample injection 
      time on the preconcentration and separation were investigated. By controlling the 
      pH at 4.6, the sample injection time was prolonged to 450 s. A very large amount 
      of melamine and dicyandiamide, bearing positive electric charges, were injected 
      into the capillary and were captured by S-GQDs. The assay using FASI 
      preconcentration and S-GQDs as enhancer resulted in a 1.6x10(5)-fold improved 
      sensitivity compared with that obtained with traditional 10-kV electrokinetic 
      injection for 10 s. The calibration curves of melamine and dicyandiamide were 
      obtained in the concentration range from 1.0x10(-14) to 1.0x10(-8)mol/L, with 
      correlation coefficients (r(2)) >0.999. The detection limits (S/N=3) were 
      2.6x10(-15)mol/L for melamine and 5.7x10(-15)mol/L for dicyandiamide. The 
      recoveries of the two analytes were 95.9%-102.4% and 92.0%-106.0%, respectively, 
      with relative standard deviations (RSDs) of no more than 5%. The RSD values of 
      peak height, peak area, and migration time were all less than 5.6%. This method 
      is reliable, easy, and exhibits a good separation effect. This proves that the 
      S-GQD-enhanced CE method could be developed into a new and sensitive technique 
      for the determination of melamine and dicyandiamide in different preparations of 
      metformin hydrochloride.
FAU - Li, Chao
AU  - Li C
AD  - Key Laboratory of Optic rectangleelectric Sensing and Analytical Chemistry for Life 
      Science, Ministry of Education; College of Chemistry and Molecular Engineering, 
      Qingdao University of Science and Technology, Qingdao 266042, China.
FAU - Wang, Qi
AU  - Wang Q
AD  - Key Laboratory of Optic rectangleelectric Sensing and Analytical Chemistry for Life 
      Science, Ministry of Education; College of Chemistry and Molecular Engineering, 
      Qingdao University of Science and Technology, Qingdao 266042, China.
FAU - Zhang, Zhaoxiang
AU  - Zhang Z
AD  - Key Laboratory of Optic rectangleelectric Sensing and Analytical Chemistry for Life 
      Science, Ministry of Education; College of Chemistry and Molecular Engineering, 
      Qingdao University of Science and Technology, Qingdao 266042, China.
LA  - chi
PT  - Journal Article
PL  - China
TA  - Se Pu
JT  - Se pu = Chinese journal of chromatography
JID - 9424804
RN  - 0 (Guanidines)
RN  - 0 (Triazines)
RN  - 7782-42-5 (Graphite)
RN  - M9B1R0C16H (dicyandiamido)
RN  - N3GP2YSD88 (melamine)
SB  - IM
MH  - Electrophoresis, Capillary/methods
MH  - *Graphite/chemistry
MH  - Guanidines
MH  - *Quantum Dots/chemistry
MH  - Triazines
PMC - PMC9404063
OTO - NOTNLM
OT  - capillary electrophoresis (CE)
OT  - dicyandiamide
OT  - melamine
OT  - sulfur-doped graphene quantum dots (S-GQDs)
EDAT- 2022/03/05 06:00
MHDA- 2022/03/08 06:00
PMCR- 2022/03/08
CRDT- 2022/03/04 05:48
PHST- 2022/03/04 05:48 [entrez]
PHST- 2022/03/05 06:00 [pubmed]
PHST- 2022/03/08 06:00 [medline]
PHST- 2022/03/08 00:00 [pmc-release]
AID - 1000-8713-40-3-289 [pii]
AID - 10.3724/SP.J.1123.2021.08017 [doi]
PST - ppublish
SO  - Se Pu. 2022 Mar 8;40(3):289-295. doi: 10.3724/SP.J.1123.2021.08017.