Determination of creatine in biological fluids

Determination of creatine, creatinine, arginine, guanidinoacetic acid, guanidine, and methylguanidine in biological fluids.

The non-specific analytical methods for the guanidinium compounds in biological fluids have been unsatisfactory for many years. The methods presented in this paper have a greatly improved specificity and are not too complex for use in the clinical laboratory. A modified Sakaguchi color reaction for substituted guanidines is used in each procedure. Guanidinoacetic acid is measured by developing ...

The Determination of Thiocyanate in Biological Fluids

Rapid determination of salicylate in biological fluids.

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Determination of Methotrexate in Biological Fluids and a Parenteral Injection Using Terbium-Sensitized Method

A new sensitive, simple and rapid method for determination of methotrexate (MTX) was developed based on quenching effects of MTX on the fluorescence intensity of Tb3+-1,10-phenanthroline complex. The fluorescence intensity was measured with excitation wavelength of 300 nm and emission wavelength of 545 nm and the quenched fluorescence intensity is proportional to the concentration of MTX in Tris...

Determination of Methotrexate in Biological Fluids and a Parenteral Injection Using Terbium-Sensitized Method

A new sensitive, simple and rapid method for determination of methotrexate (MTX) was developed based on quenching effects of MTX on the fluorescence intensity of Tb3+-1,10-phenanthroline complex. The fluorescence intensity was measured with excitation wavelength of 300 nm and emission wavelength of 545 nm and the quenched fluorescence intensity is proportional to the concentration of MTX in Tris...