ESTIMATION OF THE SPIN-LATTICE RELAXATION-TIME CONSTANTS OF LOW-MOLECULAR-WEIGHT SOLUTES IN DILUTE COMPLEX AQUEOUS-SOLUTIONS - APPLICATION TO URINARY METABOLITES

Proton spin-lattice relaxation rate constants (T-1 values) of some sel ected urinary metabolites were analysed extensively by two different l east-squares minimization procedures, based on the simplex and the Mar quardt-Levenberg algorithms. Comparative multiplicate analysis under d ifferent experimental conditions using laboratory solutions of some of the urinary metabolites was employed in addition to direct measuremen ts on human urine samples. The T-1 values estimated for most of the me tabolites by the two methods agreed to within 10-15%. (C) 1998 John Wi ley & Sons, Ltd.