Detail of "929-77-1"

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Narrow-bore wall-coated open-tubular columns for fast high-resolution gas chromatographic separations of toxicants of environmental concern

Narrow-bore wall-coated open-tubular columns for fast high-resolution gas chromatographic separations of toxicants of environmental concern. Onuska, Francis I. (Anal. Methods Div., Natl. Water Res. Inst., Burlington, ON L7R 4A6, Can. 929-77-1 and 40581-91-7 are also occured in this study.). J. Chromatogr., 289, 207-21 (English) 1984. CODEN: JOCRAM. ISSN: 0021-9673. DOCUMENT TYPE: Journal CA Section: 80 (Organic Analytical Chemistry) High-resoln. gas chromatog. columns with 100 mm I.D. can achieve better sepns. than presently used 250-mm I.D. wall-coated open-tubular (WCOT) columns in about half the total time. However, these columns also produce narrower solute peaks that require low dead vol. gas chromatog. systems. A new technique is described for static coating of such columns and their adoption for cold on-column injections and interfacing with mass spectrometer and electron-capture detectors. They can be used with present gas chromatog. equipment, usually without any system modifications. A no. of questions relating to the use of these new columns were examd. exptl. The results show no compromise in the gas chromatog. performance. A no. of applications of narrow-bore WCOT columns are presented, including comparisons of sepns. with corresponding 250 or 320-mm I.D. columns. Many difficult environmental sepns. can be resolved using narrow-bore WCOT columns. .

Quantitative Determination of Molecular Chain Tilt Angles in Monolayer Films at the Air/Water Interface: Infrared Reflection/Absorption Spectroscopy of Behenic Acid Methyl Ester

Quantitative Determination of Molecular Chain Tilt Angles in Monolayer Films at the Air/Water Interface: Infrared Reflection/Absorption Spectroscopy of Behenic Acid Methyl Ester. Flach, Carol R.; Gericke, Arne; Mendelsohn, Richard (Department of Chemistry, Rutgers University, Newark, NJ 07102, USA). Journal of Physical Chemistry B, 101(1), 58-65 (English) 1997 American Chemical Society. CODEN: JPCBFK. ISSN: 1089-5647. DOCUMENT TYPE: Journal CA Section: 66 (Surface Chemistry and Colloids) Section cross-reference(s): 36, 73 Monolayers of behenic acid Me ester at the air-water and air/D2O interfaces provide a convenient test for quant. anal.Some commonly used reagents like 929-77-1 is used in this experiment. of IR reflection-absorption spectroscopy (IRRAS) intensities. Spectra were acquired for both s- and p-polarized radiation at angles of incidence of 35, 40, 45, and 50°. The obsd. ~ 10 cm-1 splitting (at a surface pressure of 14 mN/m) for both the methylene scissoring and rocking modes provides direct evidence for the occurrence of a perpendicular orthorhombic subcell structure and for the existence of all-trans acyl chains. Anal. of the IRRAS intensities of the methylene and carbonyl stretching vibrations reveals that, of the limited set of chain tilt angles possible with respect to the surface normal, a chain tilt angle of 0° provides by far the best fit to the data. For each vibration, data for both polarizations at all 4 angles were fitted with a single set of 3 parameters, chain tilt angle, effective extinction coeff. (kmax), and overall degree of polarization (detd. by the efficiency of the polarizer and the error in its optical alignment). This last parameter is important in accounting for obsd. IRRAS intensities, esp. for p-polarized radiation close to the Brewster angle. Finally, the feasibility of by using the obsd. unequal intensities in the components of the split methylene scissoring bands to det. the angle that the orthorhombic subcell makes in the x,y (water surface) plane is demonstrated. .