scholarly journals The Nature of Rest Silanol Groups on the Surfaces of Silica Based Solid Phase Extraction Materials

2013 ◽  
Vol 650 ◽  
pp. 66-71 ◽  
Author(s):  
Alfred A. Christy
Keyword(s):  
Infrared Spectroscopy ◽  
Solid Phase Extraction ◽  
Silica Gel ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Solid Phase ◽  
Water Molecules ◽  
Phase Extraction ◽  
Modified Silica Gel ◽  
Silanol Groups

Chemically bonded solid phase materials are very important in separation chemistry. The chemically modified silica gel contains rest silanol groups that can affect the retention properties when they are used for separation of compounds. Some commercially available solid phase extraction (SPE) materials based on silica gel were analysed for rest silanol groups by near infrared spectroscopy. The combination frequency of the water molecules in the 5500- 5000 cm -1 region was used in identifying the nature of water molecules on the surface and the information was used to identify the types of silanol groups on the surface. Second derivative technique was employed in the detailed analysis. Nine different SPE materials including C18, C8, C6H5, NH2, OH, CN, SiOH, SA (SCX) and SB (SAX) were examined by near infrared spectroscopy for rest silanol groups. The results show that the non-polar and polar stationary phases contain vicinal silanol groups and the ion exchange solid phase materials contain free, vicinal and geminal silanol groups.

Effective phospholipid removal from plasma samples by solid phase extraction with the use of copper (II) modified silica gel cartridges

2017 ◽  
Vol 1070 ◽  
pp. 1-6 ◽  
Author(s):  
Jolanta Flieger ◽  
Małgorzata Tatarczak-Michalewska ◽  
Anna Kowalska ◽  
Anna Madejska ◽  
Tomasz Śniegocki ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Silica Gel ◽  
Solid Phase ◽  
Phase Extraction ◽  
Plasma Samples ◽  
Modified Silica ◽  
Modified Silica Gel

scholarly journals The Nature of Silanol Groups on the Surfaces of Silica, Modified Silica and Some Silica Based Materials

2014 ◽  
Vol 998-999 ◽  
pp. 3-10 ◽  
Author(s):  
Alfred A. Christy
Keyword(s):  
Silica Gel ◽  
Near Infrared ◽  
Water Molecules ◽  
Modified Silica ◽  
Near Infrared Reflectance ◽  
Modified Silica Gel ◽  
Silanol Groups ◽  
Near Infrared Spectra ◽  
Chemically Modified Silica ◽  
Adsorption Of Water

Silica gel, a material that is produced from the condensation polymerisation of silicic acid, contains surface silanol groups formed during the condensation. The silanol groups on the surface are mostly of free and vicinal silanol groups. These silanol groups can be modified in several different ways. Thermal treatment and hydrothermal treatment can be carried out to alter the concentration proportions between free and hydrogen bonded silanol groups on the surface. They can also be chemically treated with suitable chlorosilanes to modify the silanol groups into polar or non polar materials that can be used in separation science.This article explores the chemical nature of silanol groups on the surfaces of different materials. Near infrared reflectance spectroscopy was used as the instrumental technique in this study. The silanol groups classifications were made by analyzing the near infrared spectra obtained during the adsorption of water molecules. Absorption of the combination frequencies of water molecules in the region 5500- 5000 cm-1were used in characterizing the silanol groups on the surfaces. Second derivative technique was employed in the resolution and detailed analysis of these absorptions.The study reveals that the materials contain free, vicinal and gem silanol groups. Silica gel contains free and vicinal silanol groups, thermally treated silica gel contains fewer vicinal silanol groups compared to the base silica gel, and hydrothermally treated silica gel contains higher concentrations of vicinal silanol groups compared to the base silica gel. Furthermore, the chemically modified silica gel contains vicinal or geminal silanol groups depending on the type of functionality introduced.

Solid-phase extraction with injection of modified silica gel slurries into ETAAS for determination of Cu(II), Hg(II), Pd(II)

2018 ◽  
Vol 16 (7) ◽  
pp. 2885-2894 ◽  
Author(s):  
D. N. Konshina ◽  
M. Yu. Burylin ◽  
R. Anashkin ◽  
V. V. Konshin
Keyword(s):  
Solid Phase Extraction ◽  
Silica Gel ◽  
Solid Phase ◽  
Phase Extraction ◽  
Modified Silica ◽  
Modified Silica Gel

Solid-phase extraction and preconcentration of trace Pb(II) from water samples with folic acid modified silica gel

2012 ◽  
Vol 92 (11) ◽  
pp. 1289-1301 ◽  
Author(s):  
Qihui Wang ◽  
Xijun Chang ◽  
Zheng Hu ◽  
Dandan Li ◽  
Zhifeng Tu
Keyword(s):  
Folic Acid ◽  
Solid Phase Extraction ◽  
Silica Gel ◽  
Water Samples ◽  
Solid Phase ◽  
Phase Extraction ◽  
Modified Silica ◽  
Modified Silica Gel

Nitro-substituted 3,3′-bis(indolyl)methane-modified silica gel as a sorbent for solid-phase extraction of flavonoids

RSC Advances ◽  
2015 ◽  
Vol 5 (20) ◽  
pp. 15500-15506 ◽  
Author(s):  
Na Wang ◽  
Xiaojing Liang ◽  
Qian Li ◽  
Yuan Liao ◽  
Shijun Shao
Keyword(s):  
Solid Phase Extraction ◽  
Silica Gel ◽  
Solid Phase ◽  
Phase Extraction ◽  
Modified Silica ◽  
Modified Silica Gel

An Nbim-modified silica sorbent was synthesized and characterized for extraction of flavonoids.

Determination of trace sulfonamides in foodstuffs by HPLC using a novel mixed-mode functionalized ferrocene sorbent for solid-phase extraction cleanup

2016 ◽  
Vol 8 (31) ◽  
pp. 6099-6106 ◽  
Author(s):  
Lijun Qiao ◽  
Xiaohua Zhou ◽  
Yanhao Zhang ◽  
Ajuan Yu ◽  
Shusheng Zhang ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Silica Gel ◽  
Mixed Mode ◽  
Solid Phase ◽  
Hplc Method ◽  
Phase Extraction ◽  
Modified Silica ◽  
Modified Silica Gel

In this paper, a rapid and effective HPLC method, using a new 4-chloro-6-pyrimidinylferrocene-modified silica gel (NFcSi) as a solid-phase extraction (SPE) sorbent, was developed for the purification and determination of trace sulfonamides in foodstuffs.

Preconcentration and determination of Cu(II) in a fresh water sample using modified silica gel as a solid-phase extraction adsorbent

2010 ◽  
Vol 175 (1-3) ◽  
pp. 399-403 ◽  
Author(s):  
A.S. Pereira ◽  
G. Ferreira ◽  
L. Caetano ◽  
M.A.U. Martines ◽  
P.M. Padilha ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Water Sample ◽  
Fresh Water ◽  
Silica Gel ◽  
Solid Phase ◽  
Phase Extraction ◽  
Modified Silica ◽  
Modified Silica Gel
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