Análise química de sais de cobre fabricados entre 1877 e 1995

Samples of copper compounds covering all of the XXth century and the end of the XIXth century were submitted to classical and instrumental quantitative analysis. The amount of impurities greatly decreased with time, reaching a constant level since the 1960's. The gravimetric method was suitable for the determination of copper although other procedures also gave good or reasonable results. However, for metal contaminants, atomic absorption spectrometry was the best choice because of its lower detection limits, being able to determine several elements in the oldest samples. Ion chromatography detected several anions in copper salts manufactured before the 1950's. An increasing quality of raw materials and a better sensitivity of analytical methods led to quality improvement of copper compounds with time.