Determination of hydroxamic acids by direct
spectrophotometry of colored complex in acidic solution
Received: 22 January 2010 / Accepted: 21 May 2010 / Published online: 26 August 2010
Ó Springer Science+Business Media B.V. 2010
Abstract An improved spectrophotometry of hydroxamic acids was evaluated. A
synthetic aromatic hydroxamic acid for ﬂotation was directly determined without
any extraction in the solution of appropriate acidity. The introduction of ethanol
made the process more stable. The characteristic absorption peak of the soluble
complex at the wavelength of 525 nm was sensitive to being detected. The rela-
tionship between the absorbance and the concentration was in accordance with
Lambert–Beer’s law in the range 0–120 mg/L, with a related coefﬁcient of 0.9997.
Compared with other determinations, this method considerably reduces the period
and manipulation under the precondition of accuracy, so that it could be an available
determination for hydroxamic acids.
Keywords Hydroxamic acids Á Spectrophotometry Á Determination Á Acidity
Hydroxamic acids (R–C(=O)–NHOH), as proton donators for their special
molecular structure, can easily chelate with metallic ions to form a stable complex.
Hence, hydroxamic acids are widely used as collectors because of their high
selectivity on ﬂotation to the oxidized ores, such as rare earth, ilmenite, hematite,
and bastnaesite. Besides, they are extensively used in the realms of medical and
biochemistry pharmaceuticals, including matrix metalloproteinase (MMP) inhibi-
tors, antitumor drugs, anticancer drugs, bactericides, and herbicides.
B. Zhang Á H. Zhong (&)
College of Chemistry and Chemical Engineering, Central South University,
410083 Changsha, China
Res Chem Intermed (2010) 36:495–501