Determination of superabsorbent polyacrylate dust in workplace atmospheresafter derivatization with ethanol and using HPLC with pulsed electrochemical detection

Superabsorbent polyacrylates (SAPs) have been used in the hygiene industry for many years. A derivatization and analytical method was developed for ro utine analysis of trace levels of SAP dust in workplace atmospheres. In com parison with existing methods, which are based on the sodium content or the ion exchange properties of the polymer, this method is more specific. It h as the advantage of not being influenced by any sodium containing contamina nts. Air samples are collected on Teflon filters using air monitoring sampl ing cassettes. The filters are subsequently placed in quartz vials and a re action mixture containing hydrochloric acid in ethanol is added. The hydroc hloric acid-ethanol solution, when heated, converts the carboxylic acid gro ups on the backbone of the insoluble polyacrylate into ethyl esters. After reaction, the excess of ethanol and hydrochloric acid is completely removed under vacuum. The sample is then treated with aqueous sodium hydroxide at 80 degrees C to release the bound ethanol. The solution is analyzed by HPLC on an anion exclusion stationary phase using dilute perchloric acid as mob ile phase. Ethanol is identified and quantified with a pulsed electrochemic al detector. Several environmental samples in addition to laboratory spiked samples were successfully analyzed with this technique. Recoveries average d > 85% for spiked blank filters at levels from 5 to 50 mu g per filter wit h relative standard deviations up to 7%. The instrument's limit of detectio n (LOD) for ethanol was 0.1 mg l(-1). The LOD for derivatization and analys is corresponds to 3 mu g of SAP per filter (assuming an esterification fact or of 0.30 mu g of ethanol per mu g of SAP).