Determination of SCN- in urine and saliva of smokers and non-smokers by SCN(-)-selective polymeric membrane containing a nickel(II)-azamacrocycle complex coated on a graphite electrode.
The construction, performance characteristics, and application of a novel polymeric membrane coated on a graphite electrode with unique selectivity towards SCN- are reported. The electrode was prepared by incorporating Ni(II)-2,2,4,9,9,11-hexamethyltetraazacyclotetradecanediene perchlorate into a plasticized poly(vinyl chloride) membrane. The influences of membrane composition, pH and foreign ions were investigated. The electrode displays a near Nernstian slope (-57.8 mV decade-1) over a wide concentration range of 1 x 10(-7)-1 x 10(-1) M of SCN- ion. The electrode has a detection limit of 4.8 x 10(-8) M (2.8 ng/cm3) SCN- and shows response times of about 15 s and 120 s for low to high and high to low concentration sequences, respectively. The proposed sensor shows high selectivity towards SCN- over several common organic and inorganic anions. The electrode revealed a great enhancement in selectivity coefficients and detection limit for SCN-, in comparison with the previously reported electrodes. It was successfully applied to the direct determination of SCN- in milk and biological samples, and as an indicator electrode in titration of Ag+ ions with thiocyanate.
Ganjali
Mohammad Reza
MR
Department of Chemistry, Tehran University, Tehran, Iran. Ganjali@khayam.ut.ac.ir
Yousefi
Mohammad
M
Javanbakht
Mehran
M
Poursaberi
Tahereh
T
Salavati-Niasari
Masoud
M
Hajiagha-Babaei
Leila
L
Latifi
Elnaz
E
Shamsipur
Mojtaba
M
D001372:Aza Compounds / Q000737:chemistry*; D002138:Calibration; D004566:Electrodes / Q000592:standards; D006108:Graphite; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D011108:Polymers; D012463:Saliva / Q000737:chemistry*; D012907:Smoking / Q000378:metabolism* / Q000652:urine; D013861:Thiocyanates / Q000032:analysis* / Q000652:urine; D017186:Titrimetry
D001372:Aza Compounds; D008567:Membranes, Artificial; D009942:Organometallic Compounds; D011108:Polymers; D013861:Thiocyanates; D006108:Graphite; D009532:Nickel; C031760:thiocyanate