Developments in Crosslinking of Stationary Phases for Capillary Gas Chromatography by Cobalt-60 Gamma Radiation

Hubball, J.; Dimauro, P.R.; Barry, Eugene F.; Lyons, Edward; George, W.A.

doi:10.1093/chromsci/22.5.185

Cited by 14 publications

(6 citation statements)

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“…In summary, the dimensional stability, viscosity, and solvent resistance of a polymer are increased as a result of crosslinking. The mechanism for crosslinking 100% dimethyl polysiloxane is described below where Rž and γ (gamma radiation) are free-radical initiators: The sequence of photographs presented in Figure 3.40 permits a helpful visualization of the crosslinking process for several stationary phases, 100% dimethylpolysiloxane (SE-30), and trifluoropropylmethylpolysiloxane, as a function of increasing degree of crosslinking by 60 Co gamma radiation (114). In Figures 3.40c,d the conversion of DC200 (a silicone oil) and OV-101 (a polysiloxane fluid) to crosslinked gel versions as a function of radiation dosage is illustrated.…”

Section: Crosslinking Of a Stationary Phasementioning

confidence: 99%

“…On the other hand, for freeradical initiators that are liquid at ambient temperature, the column is first coated with stationary phase, then saturated with vapors of the reagent (47,82). Gamma radiation from a 60 Co source has also been used (77,114,(132)(133)(134)(135) as an effective technique for crosslinking polysiloxanes. In a comparative study of gamma radiation with peroxides, Schomburg et al (77) noted that each approach immobilized polysiloxanes, but that the formation of polar decomposition products is avoided with radiation.…”

Section: Crosslinking Of a Stationary Phasementioning

confidence: 99%

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Columns: Packed and Capillary; Column Selection in Gas Chromatography

Barry

2004

Modern Practice of Gas Chromatography

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Section: Crosslinking Of a Stationary Phasementioning

confidence: 99%

Section: Crosslinking Of a Stationary Phasementioning

confidence: 99%

Columns: Packed and Capillary; Column Selection in Gas Chromatography

Barry

2004

Modern Practice of Gas Chromatography

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“…Immobilization of the stationary phase is generally achieved by bonding the polymer chain to the support. This immobilization process is initiated by free radicals which are produced by heat [1][2][3][4][5] , chemical initiators such as azocompounds [6][7][8] , peroxides [9][10][11][12][13] or ozone 14,15 , and ionizing radiation such as electrons 16 , gamma radiation 17,18 and low-temperature plasmas 19 . All these methods have been successfully applied to produce immobilized nonpolar silicone phases within capillary columns.…”

Section: Introductionmentioning

confidence: 99%

Preparation of thermostable poly(ethylene glycol) using thermal treatment in sealed system

Cardoso¹,

Copetti²,

Schwerz³

et al. 2000

J. Braz. Chem. Soc.

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O trabalho descreve um método rápido para a preparação de Carbowax 20M imobilizada sobre suporte, através do uso de tratamento térmico em forno convencional. O processo de extração com solventes remove a fase estacionária não imobilizada de poli(etileno glicol) (PEG) do suporte e a diferença de massa antes e após a extração fornece o percentual extraído e, consequentemente, o percentual total imobilizado. O tratamento térmico a 250 °C por 10 horas mostrou que a imobilização reduziu a atividade do material e aumentou o número de pratos (N) e a resolução (Rs), enquanto o fator de retenção (k) reduziu. Desta forma, a separação na coluna com material tratado é mais rápida e mais eficiente. A rapid method is described for preparation of support -bonded Carbowax 20M columns packing using a conventional furnace to heat the packing. Solvent extraction of the stationary phase removes the non-immobilized poly(ethylene glycol) (PEG) from the support and the difference between final and initial weight provides the total percent extracted and, consequently, the total percent immobilized. Treatment of the packing material at 250 °C for 10 h. reveals that the immobilization reduces the material activity and increases the plates number (N) and resolution (Rs) while the retention factor (k) is decreased. Thus, separations with this treated column are faster and display higher efficiency.

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“…Another way to improve stationary phase stability is by crosslinking reactions which increase the polymer molecular mass. These immobilization processes, which involve bonding between the chains with possible bonding to the support 2 , are usually initiated by free radicals produced by heat 3,4 , chemical initiators such as peroxides 5,6 , azo compounds 7,8 or ozone 9 , low temperature plasmas 10 , or by ionizing radiation from accelerated electrons 11 or from gamma irradiation [12][13][14][15][16][17] .…”

Section: Introductionmentioning

confidence: 99%

Gamma radiation effects on polydimethylsilane stationary phases for use in packed-column gas chromatographic analyses

Adaime¹,

Santos²,

Facchin³

et al. 1999

J. Braz. Chem. Soc.

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Este trabalho estudou os efeitos da radiação gama como indutora da imobilização de fases estacionárias líquidas de polidimetilsilicones usadas para separações cromatográficas em colunas recheadas. Testes de extração em solventes mostram que doses moderadas de radiação gama (80-140 kGy) produzem imobilização (90%) da maioria dos polidimetilsilicones testados em suportes do tipo Chromosorb, apesar do efeito da massa molecular ser importante. A estabilidade térmica também aumenta significativamente, possibilitando o uso de altas temperaturas sem perdas por volatilização. Espectros no infravermelho confirmam a presença de fase estacionária no suporte após testes de estabilidade térmica e após lavagem exaustiva com solventes em coluna cromatográfica. O comportamento cromatográfico das fases imobilizadas é igual ou melhor do que o das fases não-irradiadas, exceto no caso de altas doses (300 kGy) de radiação gama. As colunas preparadas com polimetilsilicones imobilizados por radiação gama podem ser usadas com sucesso em análises onde a contaminação da coluna por compostos de alto ponto de ebulição exigem frequente recuperação da mesma. Gamma radiation induced immobilization of several polydimethylsilane liquid stationary phases for use in packed-column gas chromatographic separations has been studied. Extraction tests show that moderate doses of gamma radiation (80-140 kGy) are sufficient to produce significant (90%) immobilization of most polydimethylsilanes onto Chromosorb supports, although a molecular mass effect is seen. Thermal stability also increases significantly with radiation dose, suggesting higher temperature use with smaller volatility losses. Infrared spectra confirm the continued presence of the stationary phase on the support after thermal stability tests and after exhaustive in-column washing. The column chromatographic behavior of the immobilized phases is equal to or better than that of the unirradiated phases, except for higher doses (300 kGy) of gamma-radiation. Columns prepared from gamma-immobilized polydimethylsilane have been used successfully in analyses where column contamination from high boiling materials requires frequent column recuperation.

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Developments in Crosslinking of Stationary Phases for Capillary Gas Chromatography by Cobalt-60 Gamma Radiation

Cited by 14 publications

References 0 publications

Columns: Packed and Capillary; Column Selection in Gas Chromatography

Columns: Packed and Capillary; Column Selection in Gas Chromatography

Preparation of thermostable poly(ethylene glycol) using thermal treatment in sealed system

Gamma radiation effects on polydimethylsilane stationary phases for use in packed-column gas chromatographic analyses

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