title: Application of ion-pair methods to drug extraction from biological fluids. I. Quantitative determination of biguanides in urine.
mesh_terms: D000818:Animals; D001645:Biguanides / Q000652:urine*; D002626:Chemistry, Pharmaceutical; D004396:Coloring Agents; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008433:Mathematics; D008687:Metformin / Q000652:urine; D010629:Phenformin / Q000652:urine; D013053:Spectrophotometry; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
chemical_list: D001645:Biguanides; D004396:Coloring Agents; D007477:Ions; D008687:Metformin; D010629:Phenformin