Refractive index gradient detection of femtomole quantities of polymers by microbore size-exclusion chromatography

Hancock, Darrell O.; Synovec, Robert E.

doi:10.1021/ac00169a015

Cited by 27 publications

(25 citation statements)

References 31 publications

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“…The refractive index change for aqueous solutions of most proteins is (1-2) X 10~4 RI unit per 1% (w/v) of protein (19). Laser beam deflection should ultimately be capable of detecting angular deviation of about 1 x 10~9 rad, about 1-2 orders of magnitude below current detection limits (14)(15)(16)(17)(18).…”

Section: Introductionmentioning

confidence: 88%

“…In that context they have usually been considered to be insensitive and drift-prone. However, Dovichi and co-workers (14)(15)(16) and Synovec (17,18) have proposed laser beam deflection as a refractive index detection principle for microbore and capillary separations. In small-diameter columns and capillaries, these detectors perform much better than in large-bore systems.…”

Section: Introductionmentioning

confidence: 99%

“…Synovec (18) shows that sensitivity of about 1 mrad/0.001 refractive index (RI) unit is usually obtained in aqueous solutions. The refractive index change for aqueous solutions of most proteins is (1-2) X 10~4 RI unit per 1% (w/v) of protein (19).…”

Section: Introductionmentioning

confidence: 99%

“…These devices produce a first-derivative response. A recent variant on this design by Synovec (18,24) and a dual differential design by Pawliszyn (23) can measure refractive index differences of (2-5) X 8 RI unit. While these devices perform well, they are inherently limited to refractive index detection, or where a second laser at a suitable wavelength is available for absorbance detection via photothermal beam deflection (25).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Capillary zone electrophoresis with analyte velocity modulation. Application to refractive index detection

Chen¹,

Demana²,

Huang³

et al. 1989

Anal. Chem.

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Section: Introductionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Capillary zone electrophoresis with analyte velocity modulation. Application to refractive index detection

Chen¹,

Demana²,

Huang³

et al. 1989

Anal. Chem.

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“…An issue recently addressed by Synovec (19) and McGuffin (20) is the effect of refractive index on aperture-limited absorbance measurements. The effect is commonly manifested as an "injection disturbance" for sharp refractive index profiles (21,22) or baseline drift for MPG-LC (2). The implication of RI aberrations to absorbance measurements with TG-LC is also manifested in a drifting baseline.…”

Section: Introductionmentioning

confidence: 99%

Thermal gradient microbore liquid chromatography with dual-wavelength absorbance detection

Renn¹,

Synovec²

1991

Anal. Chem.

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and consequently that this process (which may involve the formation of carbon-carbon double bonds or of cross-linking between the polymer chains) or a similar one might be more common in the case of ion bombardment than in the case of atom bombardment. The exaggerated difference in time dependence behavior for ion beams, as compared to atom beams, observed for PTFE, as compared to PET, certainly suggests that particle-surface electronic interactions are a major contributor to this preferential sputtering of fluorine. CONCLUSIONSComparison of spectral time-dependence behavior for PET and PTFE has provided data concerning the nature of polymer degradation during particle bombardment. In particular, electronic particle-surface interactions have been shown to be a key contributing factor to degradation. In PET, this degradation is by straightforward physical degradation (random segmentation of polymer chains), which is accelerated by the use of charged primary particles. For PTFE, in addition to this process, an additional chemical degradation mechanism operates, which is, to a large extent, the consequence of electronic particle-surface interactions. This involves the preferential sputtering of fluorine and is manifested by the observation of a rise in peaks with a low fluorine to carbon ratio. At doses less than 1013 particles cmV2, this degradation mechanism may be nearly eliminated by the use of primary neutral particles rather than charged particles.Theoretical relationships are derived relating changes in the refractive index of the mobile phase in liquid chromatography to aperture limited absorbance measurements as applled to a single fiber-optic two-wavelength detector. The detection system was designed for remote sensing in thermal gradient microbore liquid chromatography (TG-pLC). TG-pLC was demonstrated with a reversed-phase separation of an unleaded gasoline sample for a temperature gradient of 25-150 OC over 30 min. The unique two-wavelength difference detection method, along with the single fiber-optic construction, virtually eliminated baseline drift associated with thermal Induced refractlve index ( R I ) aberrations. The detector provides a solution to R I aberrations not only for TEMLC but also for mobile-phase gradient liquid chromatography (MPG-LC) and other flow methods such as flow injection analyds (FIA). The advantages of TG-pLC are presented, including gradient separation capability for MLC, effective control of retention tlme comparable to MPG-LC, and separation efflclency over 72 000 theoretical plates/m using 5-pm packing material.

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Fluorometric Studies of Pyrene Adsorption on Porous Crystalline Cellulose

Tozuka

Yonemochi

Oguchi

et al. 1998

Journal of Colloid and Interface Science

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Refractive index gradient detection of femtomole quantities of polymers by microbore size-exclusion chromatography

Cited by 27 publications

References 31 publications

Capillary zone electrophoresis with analyte velocity modulation. Application to refractive index detection

Capillary zone electrophoresis with analyte velocity modulation. Application to refractive index detection

Thermal gradient microbore liquid chromatography with dual-wavelength absorbance detection

Fluorometric Studies of Pyrene Adsorption on Porous Crystalline Cellulose

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