Direct intercalation of bis-2,2',2″,6-terpyridylcobalt(III) into zirconium phosphate layers for biosensing applications.
The direct intercalation reaction of [Co(tpy)(2)](2+) with the highly hydrated θ phase of layered zirconium phosphate (θ-ZrP) resulted in the formation of the oxidized [Co(tpy)(2)](3+) ion within the ZrP material. The X-ray powder diffraction patterns showed that the interlayer distance increases from 10.3 Å in θ-ZrP to 14.9 Å in the dry [Co(tpy)(2)](3+)-intercalated ZrP {[Co(tpy)(2)](3+):ZrP} phase. The complex remains electroactive within the layers of ZrP. The formal potential of a carbon paste electrode (CPE) modified with [Co(tpy)(2)](3+):ZrP (E°' = 40.8 mV versus Ag/AgCl, 3.5 M NaCl) is non-pH-dependent. However, the sensitivity of the [Co(tpy)(2)](3+):ZrP-modified CPE for the detection of reduced nicotinamide adenine dinucleotide (NADH) electrooxidation was lower than that of a previously reported CPE modified with [Ru(phend)(2)bpy](2+)-intercalated ZrP. (1)  To improve the characteristics of NADH electrooxidation of the [Co(tpy)(2)](3+):ZrP-modified CPE, we included the enzyme diaphorase in solution, which increased the electrocatalytic current for NADH oxidation. A bienzymatic lactate biosensor was constructed and used for lactate sensing.
School of Science and Technology, Universidad Metropolitana, San Juan, Puerto Rico (PR) 00928-1150, Puerto Rico.
Mitk'El B
MB
Santiago-Berríos
Chasterie
C
Declet-Flores
Amanda
A
David
Solmarie
S
Borrero
Meredith M
MM
Vélez
Agustín
A
Díaz-Díaz
Ana R
AR
Guadalupe
Jorge L
JL
Colón
D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D009243:NAD / Q000737:chemistry; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
D009243:NAD; C027006:zirconium phosphate; D003035:Cobalt; D015040:Zirconium