Programmed temperature gas chromatography for identification of ester plasticizers

Krishen, Anoop.

doi:10.1021/ac60303a047

Cited by 16 publications

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“…Although the most common method is methanolysis with potassium or sodium methylate in methanol (9, IO), saponification followed by esterification is also frequently used (11)(12)(13). Transesterification of these polyester materials with methylate is also limited to samples with relatively low acid numbers.…”

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Rapid preparation of methyl esters from lipids, alkyd paint resins, polyester resins, and ester plasticizers

West¹

1975

Anal. Chem.

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The preparation of methyl esters from lipids has been achieved by alkali or acid transesterification, or by saponification followed by methylation of the fatty acids. Methanolysis with potassium or sodium methylate in anhydrous methanol is a simple and convenient method for the quantitative preparation of methyl esters of glyceride fats ( I , 2). Methanolic HC1 ( 3 ) or HzS04 ( 4 ) can also be used to convert lipids directly to fatty acid methyl esters. Mason and Waller ( 5 ) used dimethoxypropane to improve the methanolic HC1 method.Alkaline transesterification is mild and rapid but is limited to samples with low acid values, whereas acid catalyzed methanolysis is often a lengthy process. Therefore, saponification followed by methylation is most popular. Metcalfe et al. (6) published a quick method in which lipids are saponified with methanolic sodium hydroxide followed by refluxing with BF3 in methanol. Catalysts such as BC13 and HC1 in methanol can be used in place of BF3. Subsequently, Hartman and Lago ( 7 ) reported a readily prepared catalyst system which employs a solution of ammonium chloride and sulfuric acid in methanol, wherein HC1 is formed as primary esterification reagent. In another method ( 8 ) , tetramethylammonium hydroxide was used to saponify fats and the methyl esters were formed by pyrolysis in the injector of the gas chromatograph.Similar methods have been used to determine the acid components in alkyd paint resins, plasticizers, and polyester resins. Although the most common method is methanolysis with potassium or sodium methylate in methanol (9, IO), saponification followed by esterification is also frequently used (11-13). Transesterification of these polyester materials with methylate is also limited to samples with relatively low acid numbers. Recently, Greeley (14) reported an extremely mild method for preparing alkyl esters of acidic substances by reaction with alkyl iodides in the presence of tetramethylammonium hydroxide and N,N-dimethylacetamide/methanol solvent.This paper describes a rapid and quantitative method for preparing methyl esters from glycerides and alkyd resins and the method can be used with ester plasticizers and polyester resins. The method employs a methanolic solution of tetramethylammonium hydroxide for saponification and methyl iodide as esterification reagent. N,N-Dimethylformamide is used to provide a polar solvent for esterification. EXPERIMENTALChemicals. Tetramethylammonium hydroxide 24% in methanol was from Analabs, methyl iodide from Ajax Chemicals, and N,Ndimethylformamide was from May and Baker.Procedure. Approximately 100 to 200 mg of fatty material, alkyd resin, plasticizer, or polyester resin is added to a test tube (18 X 150 mm). If desired an internal standard such as pentadecanoic acid (approximately 30 mg per 100 mg of ester material) can be added a t this stage. Tetramethylammonium hydroxide 24% in methanol (0.5 ml) and methanol (0.5 ml) are added to the mixture which is heated in a steam bath for 10 minutes. Fat globules normally go into sol...

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Rapid preparation of methyl esters from lipids, alkyd paint resins, polyester resins, and ester plasticizers

West¹

1975

Anal. Chem.

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“…The gel permeation technique was also applied to analysis of various plasticizers. Although gas chromatography is directly applicable to lower molecular weight materials, the higher molecular weight compounds require hydrolysis and esterification for analysis (23). A mixture of phthalate esters along with dibutyl adipate and epoxidized soybean oil was separated by GPC (Figure 4).…”

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Gel permeation chromatography of low molecular weight materials with high efficiency columns

Krishen¹,

Tucker²

1977

Anal. Chem.

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“…Common coatings for such columns are listed in Table 7. Krishen [136] investigated the behavior of plasticizers in programmed temperature GC using FID detection and separation with a 10% UCW-98 on 60/80 mesh Diatoport S column. Both phthalate and nonphthalate plasticizers were included; PAEs examined include DBP, BzBP, DEHP, and DDcP.…”

Section: Characterizationmentioning

confidence: 99%

Phthalic Acid Esters

Giam

Atlas

Powers

et al. 1984

The Handbook of Environmental Chemistry

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Programmed temperature gas chromatography for identification of ester plasticizers

Cited by 16 publications

References 1 publication

Rapid preparation of methyl esters from lipids, alkyd paint resins, polyester resins, and ester plasticizers

Rapid preparation of methyl esters from lipids, alkyd paint resins, polyester resins, and ester plasticizers

Gel permeation chromatography of low molecular weight materials with high efficiency columns

Phthalic Acid Esters

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