High-performance liquid chromatographic determination of m-iodobenzylguanidine in urine of cancer patients.

An accurate, sensitive, reproducible and selective HPLC assay is presented for the quantitative determination of m-iodobenzylguanidine (MIBG) in human urine. The sample pretreatment involves a solid-phase extraction on Bakerbond SPE cyano columns. The HPLC systems consists of a muBondapak C18 column and 25 mM ammonium phosphate (pH 3.0)-acetonitrile (75:25, v/v) as the mobile phase. Detection is performed by UV absorbance at 254 nm. Log y vs. log x is the response function that yielded the smallest sum of percent relative concentration residuals over the whole concentration range of the assay (0.2-100 micrograms/ml). The excretion profile of MIBG in urine of a three-year old patient is shown.