scholarly journals Effects of terminal group and chain length on temperature-responsive chromatography utilizing poly(N-isopropylacrylamide) synthesized via RAFT polymerization

RSC Advances ◽  
2015 ◽  
Vol 5 (89) ◽  
pp. 73217-73224 ◽  
Author(s):  
Yuki Hiruta ◽  
Yuhei Nagumo ◽  
Atsushi Miki ◽  
Teruo Okano ◽  
Hideko Kanazawa
Keyword(s):  
Chain Length ◽  
Functional Group ◽  
Raft Polymerization ◽  
Stationary Phases ◽  
Terminal Group ◽  
Temperature Dependent ◽  
Temperature Responsive ◽  
Silica Beads ◽  
Elution Behavior ◽  
Terminal Functional Group

Even using the same homo poly(N-isopropylacrylamide) immobilized silica beads as stationary phases, terminal functional group and chain length significantly affected temperature-dependent elution behavior of steroids.

scholarly journals Influence of the nature of the alkanethiol terminal group on the electrochemical stability and blocking ability of self-assembled nanofilms on Au electrode

2021 ◽  
Vol 340 ◽  
pp. 01013
Author(s):  
Svetlana Ovchinnikova ◽  
Tatyana Aleksandrova
Keyword(s):  
Functional Group ◽  
Energy State ◽  
Terminal Group ◽  
Electrochemical Stability ◽  
Self Assembled Monolayers ◽  
Oh Groups ◽  
End Groups ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Terminal Functional Group

We studied the effect of the nature of the terminal group of thiols with the same chain length HS (CH2)8 – R (R: -CH3, -CH2OH, -NH2) on the electrodesorption behaviour of well-formed SAMs (the self-assembled monolayers), their stability and blocking ability using voltammetry and chronoamperometry. The nature of the terminal functional group determines the surface properties of SAM and provides the basis for subsequent interactions (for example, with peptides, proteins, DNA) in order to create sensors and bioagents. For the studied thiols, the hydrophilicity of the end groups increases in the series -CH3<< -NH2 ≤ -CH2OH; they also differ in polarity and the possibility of protonation of the amino group. For thiols with -CH3 and -CH2OH groups, an increase in the hydrophilicity of the terminal group leads to the formation of less stable and less ordered films. The replacement of carbon by nitrogen with approximately the same hydrophilicity of the groups (-CH2OH and -NH2) leads to the formation of a more stable film consisting of molecules in the same energy state, butwith poorer insulatingproperties.

scholarly journals Temperature responsive chromatography for therapeutic drug monitoring with an aqueous mobile phase

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenichi Nagase ◽  
Teruno Nishiyama ◽  
Masakazu Inoue ◽  
Hideko Kanazawa
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Organic Solvents ◽  
Drug Monitoring ◽  
Mobile Phase ◽  
Therapeutic Drug ◽  
Modified Silica ◽  
Chromatography Column ◽  
Temperature Responsive ◽  
Silica Beads ◽  
Elution Behavior

AbstractTherapeutic drug monitoring is a key technology for effective pharmacological treatment. In the present study, a temperature-responsive chromatography column was developed for safe and simple therapeutic drug monitoring without the use of organic solvents. Poly(N-isopropylacrylamide) (PNIPAAm) hydrogel-modified silica beads were prepared via a condensation reaction and radical polymerization. The temperature-dependent elution behavior of the drugs was observed using a PNIPAAm-modified silica-bead packed column and an all-aqueous mobile phase. Sharp peaks with reproducible retention times were observed at temperatures of 30 °C or 40 °C because the PNIPAAm hydrogel on the silica beads shrinks at these temperatures, limiting drug diffusion into the PNIPAAm hydrogel layer. The elution behavior of the sample from the prepared column was examined using a mixture of serum and model drugs. The serum and drugs were separated on the column at 30 °C or 40 °C, and the concentration of the eluted drug was obtained using the calibration curve. The results show that the prepared chromatography column would be useful for therapeutic drug monitoring because the drug concentration in serum can be measured without using organic solvents in the mobile phase and without any need for sample preparation.

Temperature-modulated cell-separation column using temperature-responsive cationic copolymer hydrogel-modified silica beads

2019 ◽  
Vol 178 ◽  
pp. 253-262 ◽  
Author(s):  
Kenichi Nagase ◽  
Daimu Inanaga ◽  
Daiju Ichikawa ◽  
Aya Mizutani Akimoto ◽  
Yutaka Hattori ◽  
...  
Keyword(s):  
Cell Separation ◽  
Modified Silica ◽  
Copolymer Hydrogel ◽  
Temperature Responsive ◽  
Separation Column ◽  
Silica Beads

scholarly journals Effect of pore diameter on the elution behavior of analytes from thermoresponsive polymer grafted beads packed columns

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenichi Nagase ◽  
Yuta Umemoto ◽  
Hideko Kanazawa
Keyword(s):  
Pore Diameter ◽  
Packed Column ◽  
Packed Columns ◽  
Butyl Methacrylate ◽  
Thermoresponsive Polymer ◽  
Thermoresponsive Polymers ◽  
Column Temperature ◽  
Pore Sizes ◽  
Temperature Responsive ◽  
Elution Behavior

AbstractTemperature-responsive chromatography using thermoresponsive polymers is innovative and can control analyte retention via column temperature. Analyte elution behavior in this type of chromatography depends on the modified thermoresponsive polymer and the structure of the base materials. In the present study, we examine the effect of the pore diameter of silica beads on analyte elution behavior in temperature-responsive chromatography. Poly(N-isopropylacrylamide-co-n-butyl methacrylate) hydrogel was applied to beads of various pore sizes: 7, 12, and 30 nm. Almost the same amount of copolymer hydrogel was applied to all beads, indicating that the efficiency of copolymer modification was independent of pore size. Analyte retention on prepared beads in a packed column was observed using steroids, benzodiazepines, and barbiturates as analytes. Analyte retention times increased with temperature on packed columns of 12- and 30-nm beads, whereas the column packed with 7-nm beads exhibited decreased retention times with increasing temperature. The difference in analyte elution behavior among the various pore sizes was attributed to analyte diffusion into the bead pores. These results demonstrate that bead pore diameter determines temperature-dependent elution behavior.

Molecular motions of a tetraphenylethylene-derived AIEgen directly monitored through in situ variable temperature single crystal X-ray diffraction

CrystEngComm ◽  
2021 ◽  
Author(s):  
Wei Meng ◽  
Lin Du ◽  
Lin Sun ◽  
Lian Zhou ◽  
Xiaopeng Xuan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Phenyl Ring ◽  
Functional Group ◽  
Variable Temperature ◽  
Molecular Motions ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Conformation Changes

One organic functional group was introduced to distinguish the four phenyl ring of tetraphenylethylene, and the In situ temperature-dependent crystal structures were determined to exhibit the conformation changes of tert-butyl...

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