Determination of superabsorbent polyacrylate dust in workplace atmospheresafter derivatization with ethanol and using HPLC with pulsed electrochemical detection
O. Wink et F. Schack, Determination of superabsorbent polyacrylate dust in workplace atmospheresafter derivatization with ethanol and using HPLC with pulsed electrochemical detection, ANALYST, 125(10), 2000, pp. 1745-1750
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).