P1170 ALCOHOL WIPES ARE A SOURCE OF ZINC CONTAMINATION: IMPLICATIONS FOR STUDIES ASSESSING ZINC STATUS

Abstract

Introduction: The assessment of zinc status is not straightforward and may be influenced by contamination during the pre-analytical phase. Potential sources are hair, sweat, and blood collection tubes. Although not the best indicator of whole-body zinc status, serum/plasma zinc is used most often to determine the zinc status of populations. The aim of this study was to determine whether commercial alcohol wipes or cotton wool used to prepare the skin for venepuncture could be a source of zinc contamination. Methods: The alcohol from thirty commercial alcohol wipes each, from a local (LA) and international (IA) manufacturer (same batches), was analysed for zinc content via atomic absorption spectrometry. The isopropynol from three wipes was pipetted into a test tube. Ten test tubes each were thus prepared for LA and IA. Cotton wool balls from five different manufacturers were also analysed for their zinc content. The cotton wool was immersed in 70% ethanol, and isopropynol. Results: The mean (SD) zinc concentration was 1.86 (0.11) ppm and 5.96 (0.14) ppm in 70% isopropynol for LA and IA, respectively; the CVs were 5.9% and 2.3%. The zinc content of all five the cotton wool sources was <0.1 ppm, for ethanol and isopropynol. Price of the cotton wool was not associated with zinc content. Conclusion: The results show that commercially available alcohol wipes are a source of zinc contamination. The South African product had lower zinc content, possibly because of the greater volume of alcohol per sachet. Whether this could lead to elevated serum/plasma zinc levels needs to be determined. Nonetheless, alcohol wipes should be avoided when preparing the skin for venepuncture, where serum/plasma zinc concentrations are to be determined, e.g. studies of zinc and morbidity.