Response to comment on `Empirical versus modelling approaches to the estimation of measurement uncertainty caused by primary sampling'

A binomial model is used in the analysis of our original data by Geelhoed (Analyst, 2009, DOI: 10.1039/b812422a). However, in assessing the standard uncertainty of sampling pistachio nuts for aflatoxins, the real sampling target will be much more realistically described by a continuous distribution of analyte concentration amongst the batch of nuts rather than being made up of just `contaminated and `uncontaminated nuts. The binomial assumption is therefore unlikely to be realistic enough to describe the analyte concentration distribution within a real sample population. Doing so can lead to a substantial overestimate of both the uncertainty and its confidence interval and is therefore ineffective for explaining the discrepancy between the empirical and modelling estimates in our case.