Proteins, antibodies, research grade compounds, and Reference Materials (RMs) are supplied based on the weight and concentration of the bulk material, including impurities. Thus, if a compound is supplied at 100 mg/ml and is 95% pure, the solution is 95 mg/ml compound of interest. This 5% difference will not likely have significant impact on biological experiments in vitro or in vivo, as dose responses are not typically sharp thresholds. For quantitative instrumental analysis, this would have a 5% difference in the result. The confidence interval should be determined by the investigator. To eliminate this source of error, Certified Reference Materials (CRMs) and MaxSpec® products are supplied at the certified concentration stated on the Certificate of Analysis.