Kidney Stones: Their Synthesis, Destruction, And Prevention

1. Team Members: Johnathon Cribb Michelle Pryce Shaina Stewart Marlee Stokes Kidney Stones: Their Synthesis, Destruction, And Prevention Introduction The purpose of this project was to synthesize kidney stones similar to those found in the human body due to infection. Also, after synthesis, we hoped to find different solutions or chemicals that would possibly dissolve or prevent kidney stones from forming in the first place. Kidney stones form in the urinary tract when byproducts of the urine get stuck to the inner surface of the kidney. The stones are usually formed by calcium in combination with another chemical, either oxalate or phosphate1. Most kidney stones can be passed out through the urinary tract without the aid of a doctor or physician, but other more serious stones could lead to long-term effects and may require more extensive medical attention. When stones occur in the urinary tract (ureter), doctors refer to the condition as urolithiasis. In lab, we had to develop five different solutions that would possibly precipitate to form stones. Only four of the five actually produced a precipitate, so those were the only useful ones in synthesizing our kidney stones. Once the stones were formed, we let them dry for a week and then tested different solutions to see if they would dissolve in them. Also, we used these solutions to see if kidney stones would be able to form in their presents. The results can be seen in the Results section below. Results • juice, orange juice, EDTA, and HCL acid were effective at dissolving the stones while celery seed tea and olive oil were not. As it is clear to see, the stones synthesized from reactions 2 and 3 dissolved readily during most of the tests while the stone synthesized from reaction 1 failed to do so. This result is explained by noting the poor solubility of the Oxalate ion in water. • In addition to running tests on how to dissolve the stones, tests were also carried out to investigate how to inhibit stone formation. The results from these tests can be seen in table 4. For the acids, the results that were achieved were expected. Since acids disassociate into H+ and a negatively charged ion, they prevent the stone formation from occurring by preventing the anions and cations of the insoluble salts from coming into contact with each other. The results obtained from celery seed tea and EDTA were unexpected. The EDTA should have behaved in a similar manner as the acids did, since it is a chelating agent. The results obtained from celery seed tea are currently inexplicable. • Conclusions • It was concluded that kidney stones synthesized from calcium oxalate made the best kidney stones based on physical properties, chemical properties, and actual yield as compared to theoretical yield. In order to dissolve the stones, several methods were tried. 6M HCl and 1M HCl were used successfully to dissolve each type of kidney stone. EDTA was used to successfully dissolve the stones synthesized from calcium oxalate and calcium phosphate. The remaining dissolving agents, lemon juice, celery seed tea, and orange juice only had limited success in dissolving the synthesized stones. • Lemon juice was judged to be the most promising, safest agent that could be ingested in order to dissolve kidney stones. However, with its limited effectiveness, the best method would be prevention of formation of stones. One could do this by limiting soda consumption (contains carbonate that is used to form solid stones), coffee, tea, and increasing consumption of citric fruits (could work like HCl in dissolving or preventing stone formation). • References • http://www.webmd.com/kidney-stones/kidney-stones-adults (accessed March 2007) Table 3: Results from dissolving experiments Table 4: Results from prevention tests Table 1: Initial Reactions (each row represents one reaction) + + → Reaction 1 Reaction 2 Reaction 3 Reaction 4 Equation 1: Stiochiometry Mprecipitate / MWprecipitate = Molsprecipitate Molsreactant= (Molsproduct * Coefficientreactant) _ Coefficientproduct Mreactant= Molsreactant* MWreactant Discussion During the initial planning phases, it was decided that four stone forming reactions would be analyzed. These reactions can be found in table 1. Going in order of appearance, these reactions produce the following precipitates CaC2O4 , Ca3(PO4 )2 , CaCO3 , and Mg3(PO4)2. After performing small scale tests, it was determined that the fourth reaction was not viable for purposes of this investigation as it yielded a very small amount of precipitate. Reactions, 1,2, and 3 were then synthesized. Equation 1 was utilized in determining the exact amount of reactants needed to synthesize 2.5 g of stone product. During synthesis, several differences arose between the three reactions. The most noticeable difference was see in their percent yields. As seen in table 2, reaction 1 had a percent yield of 92%, reaction 2 had a percent yield of 7%, and reaction 3 had a percent yield of 74%. The high percent yields of reaction 1 and 3 were expected, since reactions involving two insoluble ions normally go to completion. The reason for reaction 2’s low percent yield is not understood. The reaction was synthesized twice, and the second synthesis yielded similar results. This makes contamination a highly unlikely cause for these results. After a significant amount of stone was synthesized, the three types of stone were then subjected to various solvents in an attempt to dissolve them. The results results from this series of tests can be seen in table 3, and table 4. Table 3 shows the results from small scale tests carried out in a reaction well. These tests only involved approximately 0.1 g of synthesized stone; however, they showed that only lemon Table 2: Percent Yield of Reactions