Preparation of an intra-laboratory reference material--determination of the aluminum content of a pooled 5% albumin (human) solution by ETAAS, MFS and ICP-AES.

Human albumin solutions as well as other biological products intended for human use may contain aluminum as a result of intentional addition due to manufacturing protocol or through inadvertent contamination occurring during the manufacturing process. Because of the implication of aluminum in human disease, it is desirable that aluminum levels in these products be monitored. To satisfy the need for a reference material that is representative of albumin products that are intended for therapeutic use, a pooled 5% human albumin solution was prepared in bulk to serve as a reference for aluminum during analytical procedures. Aliquots of the albumin pool were analyzed for their aluminum content by three independent analytical methods, namely, electrothermal atomic absorption, molecular fluorescence and inductively coupled plasma-atomic emission spectrometry. Measured values for aluminum in the albumin solution showed good agreement between the different analytical methods. The concentration of aluminum was determined to be 0.512 microgram Al/ml by the atomic absorption method, 0.502 microgram Al/ml by molecular fluorescence, and 0.498 microgram Al/ml by the inductively coupled plasma-atomic emission method. The overall average concentration was calculated to be 0.507 microgram/ml +/- 0.009 micrograms Al/ml. The preparation of the albumin reference and its subsequent aluminum analysis is described.