PMID- 28988485
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20180731
LR  - 20180731
IS  - 1520-5827 (Electronic)
IS  - 0743-7463 (Linking)
VI  - 33
IP  - 43
DP  - 2017 Oct 31
TI  - Purification, Selection, and Partition Coefficient of Highly Oxidized Carbon Dots 
      in Aqueous Two-Phase Systems Based on Polymer-Salt Pairs.
PG  - 12235-12243
LID - 10.1021/acs.langmuir.7b02361 [doi]
AB  - In general, the methodologies for the preparation of carbon dots (CDs) lead to 
      the formation of nanostructures with size and surface chemistry heterogeneity. 
      Because the electronic and optical properties of these nanoparticles are directly 
      associated with these properties, the development of purification and selection 
      strategies is essential. Herein, we report a systematic study of the spontaneous 
      partition and separation of highly oxidized carbon dots (OCDs) prepared by the 
      dehydration and oxidation reactions of cotton cellulose in aqueous two-phase 
      systems (ATPSs) based on polymer-salt pairs. The partition of the CDs was 
      investigated in different ATPSs in which the effects of the cations and anions of 
      the salts, molecular mass and nature of the polymer, tie-line length, initial pH, 
      and surface modification of the nanoparticles on the partition coefficient (K) 
      were evaluated. The results showed that the best separation occurred with a 
      system consisting of PEO1500 + lithium sulfate + water using reduced CDs with 
      hydrazine. Alternatively, the lowest value of K, 0.79, was obtained for a 
      poly(ethylene oxide) PEO1500 + sodium tartrate + water system with pH = 6 using 
      OCDs. The detailed analyses of the top and bottom phases of the systems with 
      fluorescence and ultraviolet-visible spectroscopy showed that ATPSs are capable, 
      in addition to partitioning, of separating the nanoparticles with different 
      optical properties, which are directly associated with the surface properties and 
      particle sizes. We believe that the presented methodology is an alternative, 
      practical, fast, and potentially scalable technique for the separation of carbon 
      nanostructures with different optical properties.
FAU - Delgado, Edgard R
AU  - Delgado ER
AD  - Department of Chemistry, Federal University of the Jequitinhonha and Mucuri 
      Valleys , Rodovia MGT 367-Km 583, No. 5000, Alto da Jacuba CEP, 39100-000 
      Diamantina, Minas Gerais, Brazil.
FAU - Alves, Larissa A
AU  - Alves LA
AD  - Department of Chemistry, Federal University of the Jequitinhonha and Mucuri 
      Valleys , Rodovia MGT 367-Km 583, No. 5000, Alto da Jacuba CEP, 39100-000 
      Diamantina, Minas Gerais, Brazil.
FAU - Verly, Rodrigo M
AU  - Verly RM
AUID- ORCID: 0000-0003-0356-6862
AD  - Department of Chemistry, Federal University of the Jequitinhonha and Mucuri 
      Valleys , Rodovia MGT 367-Km 583, No. 5000, Alto da Jacuba CEP, 39100-000 
      Diamantina, Minas Gerais, Brazil.
FAU - De Lemos, Leandro R
AU  - De Lemos LR
AD  - Department of Chemistry, Federal University of the Jequitinhonha and Mucuri 
      Valleys , Rodovia MGT 367-Km 583, No. 5000, Alto da Jacuba CEP, 39100-000 
      Diamantina, Minas Gerais, Brazil.
FAU - de Mesquita, Joao P
AU  - de Mesquita JP
AUID- ORCID: 0000-0002-7089-1246
AD  - Department of Chemistry, Federal University of the Jequitinhonha and Mucuri 
      Valleys , Rodovia MGT 367-Km 583, No. 5000, Alto da Jacuba CEP, 39100-000 
      Diamantina, Minas Gerais, Brazil.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20171019
PL  - United States
TA  - Langmuir
JT  - Langmuir : the ACS journal of surfaces and colloids
JID - 9882736
EDAT- 2017/10/11 06:00
MHDA- 2017/10/11 06:01
CRDT- 2017/10/10 06:00
PHST- 2017/10/11 06:00 [pubmed]
PHST- 2017/10/11 06:01 [medline]
PHST- 2017/10/10 06:00 [entrez]
AID - 10.1021/acs.langmuir.7b02361 [doi]
PST - ppublish
SO  - Langmuir. 2017 Oct 31;33(43):12235-12243. doi: 10.1021/acs.langmuir.7b02361. Epub 
      2017 Oct 19.