Summary III Summary This thesis includes four chapters: Chapter one is an introduction to Phytochemistry with a general literature survey about the natural pigments. It also deals with a survey for the sweet cherry (Prunus avium L.) fruit. Chapter two deals with the extraction of pigments (quercetin) and (cyanidin-3-glucoside) with ultrasound assistance (for 1 hour) from the Iraqi Kurdistan cherry fruit. Different solvents were used during 24 hours at room temperature, the best solvent was found to be 80% methanol which gave the highest extract yield (15.95%). The extracted pigments were purified using chemical and physical methods including different chromatographic techniques (TLC, PTLC, and column chromatography). The pure extracted pigments were identified using HPLC and different spectroscopic techniques such as infrared, ultraviolet-visible 1 13 spectrophotometry, H-NMR, C-NMR and elemental analysis. The purified pigments were hydrolyzed to identify attached sugar. The biological activity of the extracted pigments were determined against two common types of bacteria which were Staphylococcus aureus (gram +ve) and Escherichia coli (gram –ve), the results indicates that the anthocyanin compound (cyanidin-3-glucoside) has inhibited each types of bacteria. Chapter three describes the stability of the extracted pigment (cyanidin-3-glucoside) towards the solvents, temperature and pH effects and this pigment was applied as a very useful indicator in visual acid-base titration in aqueous medium. Double detection devices; spectrophotometer and potentiometer were simultaneously used in this titration. This indicator was accurate and precise for three types of neutralization titration: strong acid-strong base, strong acid-weak base and weak acid-weak base titration, Summary IV while for the titration of weak acid against strong base the value of relative error was more than 30%. Chapter four deals with a new and simple flow injection analysis with chemiluminescence (CL) system for determination of quercetin through the reverse flow injection technique. The method was based on the inhibition of the CL of H2O2–luminal-permanganate with quercetin which is systematically decreased the CL-intensity with increasing the concentration of quercetin. The reverse flow was used to avoid continuous monitors of CL which leads to unstable baseline. Various parameters associated with this flow system were studied and essential optimizations were carried out. Two calibration graphs were constructed for determination of quercetin in the range (6.0–12 μg/ml) with correlation coefficient (0.9994) for low concentration level and (20–190 μg/ml) with correlation coefficient (0.9962) for high concentration and a sampling frequency 80 samples/h. Possible interferences were studied and the results showed that the interferences caused less than 5% error. The method was applied successfully for the determination of quercetin in various natural products.