[en] Gas-liquid chromatography (GLC) and thin-layer chromatographic (TLC) procedures have been developed for the estimation of monobutyl phosphoric acid (H₂MBP) and dibutyl phosphoric acid (HDBP) present in tributyl phosphate (TBP). Less than one microgram of H₂MBP and HDBP is visually detected on TLC plate made of silicagel-cellulose (1:1). HDBP as separated by TLC has been quantitatively estimated in the range of 40-260 μg using an indirect spectrophotometric method. GLC method using 10 percent (W/W) XE-60 column can be effectively used for the simultaneous determination of 0.25 percent W/V H₂MBP and HDBP present in 30 percent TBP-n-dodecane. The sensitivity may be enhanced 100 fold by careful column conditioning and judicious control of operational parameters. (author)