Yoonsun Mo | PubMed Health

PubMed2003

A simple HPLC method with pulsed EC detection for the analysis of creatine.

The objective of this study was to develop a simple and sensitive LC method for the determination of creatine in aqueous solutions as well as in rat plasma using electrochemical detection. The chromatographic system consisted of a GP50 gradient pump, an ED40 pulsed electrochemical detector, and an AI-450 chromatography automation system (Dionex). The mobile phase consisted of a mixture of water, acetonitrile, 0.01 M sodium acetate, and 1.0 M sodium hydroxide (2.5:2.5:90:5, V/V/V/V) at a flow rate of 1.0 ml/min. The chromatographic separation was achieved at 45 degrees C on a column with a polyhydroxylated glucose and sulfonated stationary phase. The retention times of creatine and creatinine was 3.50 and 4.73 min, respectively, with creatine fully resolved from its major degradation product, creatinine. The standard curves were linear over the concentration range of 0-20 microg/ml. Within-day and day-to-day relative standard deviations (R.S.D.) were less than 10%. This method was used to study dissolution characteristics of various creatine salts in water.

Animals↗

PubMed2002

Solid-state properties of creatine monohydrate.

Creatine monohydrate (CM) is a nutritional supplement and an ergogenic aid for athletes. It appears to increase lean body mass, high-intensity power output and strength in healthy humans. The crystal structure of creatine monohydrate has previously been reported. However, little information is available on its solid-state properties. In this investigation, creatine monohydrate was subjected to Thermal Analyses, Karl-Fisccher Titrimetry (KFT), Scanning Electron Microscopy (SEM), and Variable Temperature X-ray Powder Diffractometry (VTXRD) to characterize its solid-state properties. The results of this study suggested that commercially available creatine monohydrate dehydrates at about 97-125 degrees C. A phase transition after dehydration was confirmed by X-ray diffraction studies. This dehydrated phase at a temperature above 230 degrees C undergoes intramolecular cyclization with a loss of an additional mole of water to form creatinine. Creatinine finally melts with decomposition at about 290 degrees C. VTXRD, confirmed that the above solid-state thermal transformation was kinetically driven, and occurred within a narrow temperature range. Mass Spectrometric (MS) studies further indicated a possible dimerization of creatinine formed during the solid-state transformation.

Chemical Phenomena↗