Column Extraction of Metal from Liquid Monomers

1 Column Extraction of Metal from Liquid Monomers 

A study of column extraction of metals was carried out using pre-packed columns available from Polymer Laboratories (now a part of Varian, Inc.) [6]. Trace metals in these monomers would have a detrimental effect on the stability of anaerobic adhesive products and must be absent prior to use. The columns used are specially coated macroporous polystyrene products that are compatible with polar, non-polar, protic and aprotic solvents. They are designed to remove metals from solvents and monomers. The metal removing SPE product is approximately 45 pm and based on a mono-dispersed macroporous polymeric material. 

Column 1 PL (Thiol MP SPE) Column 2, PL (Urea MP SPE) Column 3, PL (Thiorea MP SPE) -CH2NHSNHCH2CH3 -CH2NHCONHCH2CH2CH2CH3 -(SH)2 

Method. Three columns containing PL-Thiol MP SPE, PL-Urea MP SPE and PL-Thiourea MP SPE (available from Polymer Laboratories Ltd) are studied to test the efficiency of extraction of metals from ethylene glycol dimethacrylate dissolved in methanol. The spiked and non-spiked monomer are dissolved in ethanol at 5% concentration and a 10.0 ml solution of each monomer is passed through the columns using a vacuum suction water pump. The columns containing the metals are washed with 1.0 ml of 0.25 M HC1 and extracts made up to 25.0 ml in plastic volumetric flasks with deionised water. Extracts are analysed for metal content against standards of 0.0, 0.1, 0.25 and 0.5 ppm of Cu, Fe, Co and Ni prepared in 0.25 M HC1. 

Results. Column extraction offers a new method of sample preparation and can be applied to liquid raw materials and solids that are solvent soluble. The column extraction method is promising and offers an efficient alternative for a range of materials. Excellent extractions of Cu, Fe, Co and Ni are obtained with the PL-Thiourea, while only Cu and Fe are extracted with the PL-Thiol column for this monomer (Table 6.9). 

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