EDTA

EDTA (Ethylenediaminetetraacetic acid)

EDTA Nedir?

EDTA bileşiği Etilendiamin tetraasetik asit'in kısaltmasidir. EDTA polyamino karboksilik asid bileşiğidir.

Genel formülü ise [CH₂N(CH₂COOH)₂]₂ şeklindedir.

Yapısal formülü için;

http://upload.wikimedia.org/wikipedia/commons/thumb/8/85/Ethylenediaminetetraacetic.png/200px-Ethylenediaminetetraacetic.png

EDTA'nın Kimyasal Özellikleri

CAS No: 60-00-4

Molekül Formülü: C₁₀H₁₆N₂O₈

Molekül Ağırlığı: 292.24 g.mol⁻¹

Yoğunluğu: 0,86 g/cm³

Erime noktası: 240 °C

Asidite;

pK1=0.0 (CO2H) (µ=1.0)

pK2=1.5 (CO2H) (µ=0.1)

pK3=2.00 (CO2H) (µ=0.1)

pK4=2.69 (CO2H) (µ=0.1)

pK5=6.13 (NH+) (µ=0.1)

pK6=10.37 (NH+) (µ=0.1)

EDTA'nın Keşfi

EDTA ilk olarak Ferdinand Munz tarafından tanımlanmıştır. Munz, EDTA'nın keşfini etilendiamin ve klorasetik asit çözeltilerinden elde etmiştir.

H₂NCH₂CH₂NH₂ + 4 CH₂O + 4 NaCN + 4 H₂O → (NaO₂CCH₂)₂NCH₂CH₂N(CH₂CO₂Na)₂ + 4 NH₃

(NaO₂CCH₂)₂NCH₂CH₂N(CH₂CO₂Na)₂ + 4 HCl → (HO₂CCH₂)₂NCH₂CH₂N(CH₂CO₂H)₂ + 4 NaCl

Poliamino karboksilik asid grubundan olan EDTA’nın kimyasal yapısına bakıldığında 2 amino 4 karboksil ligandı vardır. EDTA metal iyonlarına karşı yüksek afinite gösterir.

[Fe(H₂O)₆]³⁺ + H₄EDTA ${\displaystyle \rightleftharpoons }$ [Fe(EDTA)]⁻+ 6 H₂O + 4 H⁺ (K_eq = 10^25.1)

EDTA’nın Laboratuvarda Kullanımı

EDTA laboratuvarda metal iyonlarını tutmak için kullanılır. Biyokimya ve moleküler biyoloji iyon tüketici olarak enzimlere karşı kullanılır. Analitik kimya da kompleksometrik titrasyon, Su sertliği maskeleyici ajanlar analizelerinde kullanılır.

Kaynaklar

1 ^ Harris, D.C. "Quantitative Chemical Analysis", 7th ed., W. H. Freeman and Compagny, New York, 2007 2 ^ F. Munz "Polyamino carboxylic acids to I. G. Farbenindustrie, DE 718 981, 1935; US 2 130 505, 1938. 3 ^ Synthesis of EDTA 4 ^ a b c J. Roger Hart "Ethylenediaminetetraacetic Acid and Related Chelating Agents" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. 5 ^ Kirchner, S. Barium (Ethylenediaminetetracetato) Cobalt(III) 4-Hydrate" Inorganic Syntheses, 1957, Volume 5, pages 186-188. 6 ^ Edta - Motm 7 ^ Holleman, A. F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 0-12-352651-5. 8 ^ Furia T (1964). "EDTA in Foods — A technical review". Food Technology 18 (12): 1874–1882. 9 ^ a b c Lanigan RS and Yamarik TA (2002). "Final report on the safety assessment of EDTA, calcium disodium EDTA, diammonium EDTA, dipotassium EDTA, disodium EDTA, TEA-EDTA, tetrasodium EDTA, tripotassium EDTA, trisodium EDTA, HEDTA, and trisodium HEDTA". Int J Toxicol. 21 Suppl 2: 95–142. http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=12396676&dopt=AbstractPlus. Retrieved 2008-01-28. 10 ^ US Food and Drug Administration: Center for Food Safety and Applied Nutrition Questions and Answers on the Occurrence of Benzene in Soft Drinks and Other Beverages 11 ^ Ruth DeBusk et al. (2002). "Ethylenediaminetetraacetic acid (EDTA)". http://www.umm.edu/altmed/articles/ethylenediaminetetraacetic-acid-000302.htm. Retrieved 2007-07-25. 12 ^ "Home > Medical Reference > Complementary Medicine > EDTA overview". University of Maryland Medical Center. http://www.umm.edu/altmed/articles/ethylenediaminetetraacetic-acid-000302.htm. Retrieved 16 December 2009. 13 ^ Loren, Karl (1996). "I/V Chelation Using EDTA Life Flow One The Solution For Heart Disease". The Thinking Person's Guide to Perfect Health. Vibrant Life. http://www.oralchelation.net/data/EDTA/data14e.htm. Retrieved 16 December 2009. 14 ^ See "les conservateurs en opthalmologie" Doctors Patrice Vo Tan & Yves lachkar, Librarie Médicale Théa. 15 ^ Green, Saul; Wallace Sampson (December 14, 2002). "EDTA Chelation Therapy for Atherosclerosis And Degenerative Diseases: Implausibility and Paradoxical Oxidant Effects". Quackwatch. http://www.quackwatch.org/01QuackeryRelatedTopics/chelationimp.html. Retrieved 16 December 2009. 16 ^ http://www.clinicaltrials.gov/ct/show/NCT00044213?order=2 17 ^ Margolock, David (July 26, 1995). "F.B.I. Disputes Simpson Defense on Tainted Blood". The New York Times: pp. A12. http://query.nytimes.com/gst/fullpage.html?sec=health&res=990CE4DD1F3DF935A15754C0A963958260. Retrieved 16 December 2009. 18 ^ Zhiwen Yuan, Jeanne M. VanBriesen "The Formation of Intermediates in EDTA and NTA Biodegradation" Environmental Engineering Science 2006, volume 23, pp. 533–544. doi:10.1089/ees.2006.23.533 19 ^ a b Robin L. Sheppard, and Jack Henion (1997). "Determining EDTA in Blood" ([dead link] – Scholar search). Analytical Chemistry 69: 477A–480A. http://pubs.acs.org/hotartcl/ac/97/aug/det.html. Retrieved 2007-07-25. 20 ^ S. Loyaux-Lawniczak, J. Douch, and P. Behra (1999). "Optimisation of the analytical detection of EDTA by HPLC in natural waters". Fresenius' J. Anal. Chem. 364 (8): 727–731. doi:10.1007/s002160051422. http://cat.inist.fr/?aModele=afficheN&cpsidt=1898737. Retrieved 2007-07-25. 21 ^ Carolina E. Cagnassoa, Laura B. López, Viviana G. Rodríguez and Mirta E. Valencia (May 2006). "Development and validation of a method for the determination of EDTA in non-alcoholic drinks by HPLC". Journal of Food Composition and Analysis 20 (3-4): 248. doi:10.1016/j.jfca.2006.05.008 22-Ege üniversitesi Deri müh. bölümü.(G.E) www.ege.edu.tr