Comparison of aggregate exposure approaches in the risk assessment of parabens
2012; Elsevier BV; Volume: 211; Linguagem: Inglês
10.1016/j.toxlet.2012.03.154
ISSN1879-3169
AutoresIlse Gosens, Christiaan Delmaar, Wouter ter Burg, Jacqueline W.H. Biesterbos, Natalie von Goetz, Martine Bakker, Cees de Heer, Gerlienke Schuur,
Tópico(s)Radioactive Decay and Measurement Techniques
ResumoCertified reference materials (CRMs) of water content are widely used in the calibration and validation of Karl Fischer coulometry and volumetry. In this study, the water content of the water saturated 1-octanol (WSO) CRM was certified by Karl Fischer coulometry, volumetry and quantitative nuclear magnetic resonance (Q NMR). The water content recovery by coulometry was 99.76% with a diaphragm-less electrode and Coulomat AG anolyte. The relative bias between the coulometry and volumetry results was 0.06%. In Q NMR, the water content of WSO is traceable to the International System (SI) of units through the purity of internal standard. The relative bias of water content in WSO between Q NMR and volumetry was 0.50%. The consistency of results for these three independent methods improves the accuracy of the certification of the RM. The certified water content of the WSO CRM was 4.76% with an expanded uncertainty of 0.09%.
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