TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: A solid acid catalyst is used in a liquid phase reaction during manufacture of biodiesel. The solid acid is a heteropolyacid that is connected with a support material. The support material is a solid support, preferably solgel. The support is a porous support. The heteropolyacid is a monovalent cation doped heteropolyacid. The monovalent cation salt is cesium salt containing cesium halide such as cesium chloride. The monovalent cation doped heteropolyacid is of formula: Y'xH(n-x)MX12O40, preferably CsxH(3-x)PW12O40 or CsxH(4-x)SiW12O40.M=phosphorus or silicon;Y'=ammonium ion, sodium ion, potassium ion or cesium ion;X=tungsten or molybdenum;n=3 or 4;andx=more than 0 to less than 3.When M is phosphorus x is less than 2.5, when M is silicon n is 4. Preferred Compound: The support comprises 1 or more inorganic oxides such as silica. The silica support is coated with 1 or more zirconium salt such as zirconium oxide, zirconium phosphate or zirconium sulfate. Preferred Property: The support has average pore diameter of 40-170 Angstrom , preferably 100-170 Angstrom , Brunauer-Emmett-Teller surface area of 250-1000 m2/g, preferably 250-600 m2/g, more preferably 350-400 m2/g . The support has hydroxyl content of 0.1-1.5 mmol/g. The support has Barret Joiner Halenda pore volume of 0.8-1.6 cm3/g, preferably 1-1.4 cm3/g.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The esterified or transesterified feedstock is supplied to a column containing a separation material and the ester content of the feedstock is separated. Thus, analysis of biodiesel is carried out. Preferred Compound: An organic acid such as fatty acid is used for esterfication. An organic ester such as fatty ester is used for transesterfication. The feedstock is selected from beef tallow, cow oil, palm oil, peanut oil, rapeseed oil, soybean oil, sunflower oil, jatropha oil, hungmai oil, mauha oil, nohr oil and/or sal oil. The feedstock further comprises used cooking oil. 1-8C alcohol is used during esterification or transesterification process. The alcohol is a primary or secondary monohydric aliphatic alcohol such as methanol, ethanol, propanol, butanol or amyl alcohol. Preferred Material: The support is hydrophobic. The support further comprises alkyl or aromatic compounds. The column is a high performance liquid chromatography column.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compound: The separation material contains a lipophilic polymer. The lipophilic polymer comprises a lipophilic 19C or more hydrocarbon chain, preferably 30C hydrocarbon chain. Preferred Definitions:    M=phosphorus;    X=tungsten;    x=0.9-2.35, preferably 1.95-2.35, more preferably 2-2.3 ;and    n=3.