A preliminary study on the effect of time on apparent lead content of evaporated milk as determined by non-flame atomic-absorption spectrometry.
Analysis of several brands of canned evaporated milk at various times after opening showed increases in the lead content upon standing. Initially all samples had a lead content within the range 0.1-0.2 ppm. Upon standing, however, the lead concentration of anumber of samples doubled or tipled. Control samples obtained by pouring approximately half of the milk from a can into a polyethylene bottle immediately after opening showed no such increase. When atmospheric oxygen was ecluded by bubbling nitrogen through a sample, where was likewise no increase in lead for the sample. Bubbling oxygen through the samples produced an increase in the lead content of the milk left in the can but did not affect that of the milk in the polyethylene bottle.