3. N-acetyl aspartate(NAA) C 6 H 9 NO 5 EX OF N-Acetyl Amino acids

4. Decreased levels of NAA 1- Alzheimer’s disease 2- AIDS 3- schizophrenia 4- Huntington’s disease 5- amyotrophic lateral or multiple sclerosis 6- traumatic brain injury high levels of NAA : causes Canavan’s disease The interest in N-acetylaspartate determination is due to it present in high concentration in the brain and their possible direct impact on the human as :

5. 1-Magnetic resonance spectroscopy The major advantage of 'H NMR spectroscopy is that this technique can be applied to in vivo studies of brain The major disadvantage of NMR is its low sensitivity, allowing only metabolites present at relatively high concentration to be measured.

6. Advantages of HPLC Sensitivity Accuracy Automation Disadvantages of HPLC Complexity The analysis time is long A further principal drawback of these methods is the requirement of (sometimes harmful) organic solvents of HPLC grade quality, whereby the costs for their purchase and disposal has to be taken into consideration 2-Chromatographic techniques HPLC, Gas and Liquid chromatography High resolution

7. Luminescence is a highly sensitive analytical method nowadays, its interest for medical analysis and diagnosis. One of the most convenient and simplest detection method is based on the change in absorption or luminescence in the presence of an analyte. The lanthanide complexes, with characteristically narrow excitation and emission bands, intense luminescence, and long excited-state lifetimes, have drawn considerable interest for their potential application as luminescence imaging agents and sensors.