4. Analysis of real samplesWe analyzed 15 milk samples of brands commonly found inthe supermarkets of Rome. Ten were fresh pasteurized milk (fourwhole milk, three semi-skimmed milk, one lactose-free milk, two high-quality milk), and five UHT milk. All of them were analyzed induplicate. Though our method had lower MQLs than other recentlypublished methods [5,15], none of them was found contaminatedover our MQL, for any of the compounds analyzed. For 4 out 15samples we found amount of one or more compounds betweenMDL and MQL, but this was not confirmed in the duplicate sample.This fact was probably due to the difficult in maintaining constant,low blank values in conditions of reproducibility.