Succinate polyester

The GC separation of esters and the selection of the stationary phase represent problems of varying degrees of complexity in individual cases. An acceptable separation can usually be obtained on different polyester stationary phases (EGA, butanediol succinate polyester, EGS, etc.), Carbowax-type phases, OV-17, OV-225 and SE-30. Non-selective and non-specific stationary phases are preferred. The supports should not be acidic, and they are sometimes modified by silanization. In particular instances, when other groups are also derivatized prior to the analysis the selection of the stationary phase may be very difficult. These problems are discussed for individual types of compounds in Chapter 5. 

Enantiomers of carboxylic acids may sometimes be separated by GC as methyl esters, but special derivatives are mostly prepared for this purpose. Ackman et al. [188] resolved enantiomers of isoprenoid fatty acids after their conversion into L-menthyl esters. The acids under analysis were chlorinated by refluxing with distilled freshly prepared thionyl chloride and the chlorides produced were treated with L-menthol in the presence of pyridine under strictly anhydrous conditions. GC separation was carried out in a capillary column coated with butanediol succinate polyester. Annett and Stumpf [189] made use of L-menthyloxycarbonyl derivatives for the separation of enantiomers of methyl esters of hydroxy acids. The derivatization reagent, L-menthyl chloroformate, was prepared by the reaction of L-menthol with phosgene, with cooling with ice. Diastereoisomers of different hydroxy acids were thus separated on 1.5% OV-210. 

Dimethylpolysiloxane oil Dimethylpolysiloxane gum 50% Phenyl-50 /o methylpolysiloxane Diethylene glycol succinate polyester 3-Cyanopropylpolysiloxane Trifluoropropylmethylpolysiloxane 50 /o 3-Cyanopropyl-50% phenylmethyl-silicone... 

Methylvinylpolysiloxane Polyamide formed by reacting a Cye dicarboxylic acid with l,3-di-4-piperdyl-propane and piperidine in the respective mole ratios of 1.00 0.90 0.20 5is (2-ethylhexyl) sebacate polyester Phenyldiethanolamine succinate polyester Sorbitol... 

Column Glass-U-tubes, 6 foot X 4 mm i.d. Gas Chrom P 80-100 or 100-120 mesh, acid-washed, dichlorodimethylsilane treated. Liquid phases were (1) F-60-Z a mixture of 7% F-60 (a methyl-p-chlorophenylsiloxane polymer) and 1% EGSS-Z (a copolymer of ethylene glycol, succinic acid, and a methylphenylsiloxane monomer) and (2) 10% neopentyl glycol succinate polyester (NGS) (3) 1.25% SE-30 (4) 3% DC-710 (5) 0.6% JXR (methylsiloxane polymer) and 0.2% cyclohexanedimethanol succinate polyester (CHDMS). 

Column 6 foot X inch glass column packed with 15% ethyleneglycol succinate polyester (EGS) on Chromosorb W (80-100 mesh). 

Fig. 4.—Separation of Fully Methylated Methyl Glycosides of Sugars Present in Maple-sap Arabinogalactan. (Key (I) methyl 2,3,4-tri-O-methyl-a-L-rhamnopyrano-side (II and III) methyl 2,3,5-tri-0-methyl-a,/3-L-arabinofuranosides (IV) methyl 2,3,4-tri-0-methyl-a,j3-L-arabinopyranosides (V) methyl 2,3,5,6-tetra-0-methyl-o,/3-D-galactofuranosides (VI) methyl 2,3,4,6-tetra-0-methyl-a,/3-D-galactopyranosides. Conditions column (4 ft. x 4 mm.) of butanediol succinate polyester on Celite (2 8 w/w) 150° 150 ml. of argon/min. /3-ionization detector.)...

Fig. 5.—Separation of Fully Methylated Methyl o-Glucosides and Methyl n-Fructo-sides. (Key (1) methyl 2,3,4,6-tetra -methyl- D-glucopyranoside (2) methyl 1,3,4,6-tetra-O-methyl-o-D-fructofuranoside (3) methyl l,3,4,6-tetra-0-methyl- 3-D-fructo-furanoside (4) methyl 2,3,4,6-tetrarO-methyl-a-D-glucopyranoBide (5) methyl 1,3,4,5-tetra-O-methyl-a-D-fructopyranoside (6) methyl 2,3,5,6-tetra-0-methyl-( )-D-gluco-furanoside (7) methyl 2,3,5,6-tetra-0-methyl-( )-D-glucofuranoside (8) methyl 1,3,4,5-tetra-O-methyl-jS-D-fructopyranoaide. Conditions column (5 ft. x 2 mm.) of 5% diethyleneglycol succinate polyester on Chromosorb W 136° 16 ml. of helium/min. thermal-conductivity detector.)...

All packings were commercial products 1, 1,4-butanediol succinate polyester 2, diethylene glycol succinate polyester 3, diethylene glycol succinate polyester that had heen used extensively for analysis of fatty acid esters. 

The relative intenaitiea of peaka are indicated as strong (s), medium (m), weak (w), and very weak (vw). Incomplete resolution is indicated by shoulder (sh). Conditions Column (120 X 0.5 cm.), 15% by weight of 1,4-butanediol succinate polyester on acid-washed Celite (80-100 mesh) 175° 80-100 ml. of argon/min. /3-ionization detector. Conditions Column (120 X 0.5 cm.), 10% by weight of polyphenyl ether [w-bis-(m-phenoxyphenoxy)benzene] on acid-washed Celite (80-100 mesh) 200° 80-100 ml. of argon/min. ionization detector. As the methyl ester. 

A sensitive method for the detection and separation of micro quantities of cyclic acetals of sugars by means of gas-liquid, partition chromatography has been described by Jones and coworkers. The column packing consisted of an intimate mixture of Apiezon M grease on Cromosorb W and butanediol succinate polyester on Cromosorb W, which was packed on top of a column of SE-30 methylsilicone polymer and glass beads. The column temperatme was maintained at 200°. Some cyclic acetals of sugars have been fractionated by gas-liquid chromatography as their (trimethyl-silyl) ethers. These derivatives are conveniently prepared and the method is especially suited to the less volatile monoacetals. 

Preparative gas chromatography was used to separate the cyclodo-decene isomers. An Aerograph A-700 instrument with a 20-foot X 3/8 inch diethylene glycol succinate polyester column at 160 °C. was used. The crude fractions were rechromatographed to obtain samples of ca. 99.8% purity. 

Jones and coworkers were the first to report a separation of carbohydrate acetals by gas-liquid chromatography. They employed a column (117 x 0.5 cm inside diameter) packed with 40 cm of an intimate 1 1 (v/v) mixture of 20% (wt./wt.) Apiezon M grease on Chromosorb W and 20% (wt./wt.) of butanediol succinate polyester on Chromosorb W, on top of 77 cm of 1% (wt./wt.) of SE-30 medium on glass beads. The temperature of the column was kept at 206°. With... 

G34 Diethylene glycol succinate polyester stabilized with H3PO4 Rt-DEGS PS, DEGS-PS... 

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