Simultaneous Voltammetric Determination of Uric Acid, Xanthine, and Hypoxanthine Using CoFe<sub>2</sub>O<sub>4</sub>/Reduced Graphene Oxide-Modified Electrode

<div>(a) DPV curves of UA, XA, and HX oxidations on the modified electrode at different pH. (b) Effects of pH on the anodic peak currents (<span class="nowrap"><svg height="14.0004pt" id="M22" style="vertical-align:-5.3645pt" version="1.1" viewbox="-0.0498162 -8.6359 10.1207 14.0004" width="10.1207pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M405 650H141L135 622C222 616 230 610 215 535L133 116C118 41 113 33 29 28L23 0H289L295 28C209 33 205 40 219 116L298 535C312 609 317 616 399 622L405 650Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.719,3.132)"><path d="M169 380V459C122 440 66 423 24 416V392C86 384 90 382 90 317V-135C90 -201 81 -207 17 -213V-240H253V-213C176 -207 169 -201 169 -125V6C182 -1 208 -11 238 -12C368 12 487 109 487 260C487 358 421 449 310 449C298 449 279 444 261 433L169 380ZM169 346C196 367 237 389 269 389C341 389 403 329 403 221C403 109 347 37 263 37C228 37 191 53 169 76V346Z"></path></g></svg>).</span> (c) The linear plot of anodic peak current (<span class="nowrap"><svg height="14.0004pt" id="M23" style="vertical-align:-5.3645pt" version="1.1" viewbox="-0.0498162 -8.6359 10.1207 14.0004" width="10.1207pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M405 650H141L135 622C222 616 230 610 215 535L133 116C118 41 113 33 29 28L23 0H289L295 28C209 33 205 40 219 116L298 535C312 609 317 616 399 622L405 650Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.719,3.132)"><path d="M169 380V459C122 440 66 423 24 416V392C86 384 90 382 90 317V-135C90 -201 81 -207 17 -213V-240H253V-213C176 -207 169 -201 169 -125V6C182 -1 208 -11 238 -12C368 12 487 109 487 260C487 358 421 449 310 449C298 449 279 444 261 433L169 380ZM169 346C196 367 237 389 269 389C341 389 403 329 403 221C403 109 347 37 263 37C228 37 191 53 169 76V346Z"></path></g></svg>)</span> vs. pH (<svg height="14.7455pt" id="M24" style="vertical-align:-3.3094pt" version="1.1" viewbox="-0.0498162 -11.4361 166.714 14.7455" width="166.714pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M645 631C614 643 545 666 457 666C215 666 23 519 23 283C23 90 158 -16 337 -16C412 -16 489 2 522 10C543 39 590 127 606 167L580 181C519 89 459 18 348 18C201 18 122 136 122 287C122 464 244 632 435 632C544 632 602 595 608 472L639 475C643 526 645 581 645 631Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.619,3.132)"><path d="M716 650H478V622C549 617 570 605 575 566C579 535 582 493 582 401V326C582 161 537 40 393 40C269 40 205 133 205 294V521C205 611 213 617 291 622V650H33V622C111 615 120 611 120 521V272C120 154 148 80 208 34C252 0 309 -14 368 -14C434 -14 501 7 548 55C605 116 623 201 623 319V401C623 493 626 536 629 563C633 605 656 618 716 622V650Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,14.604,3.132)"><path d="M673 0V28C608 34 594 43 563 129C499 303 432 494 370 665L339 656L132 132C98 43 84 37 20 28V0H238V28C162 35 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Other conditions are as in Figure <a href="../fig8/">8</a>.</div>

Journal of Nanomaterials

fig10

Figure 10

Figure 10: Simultaneous Voltammetric Determination of Uric Acid, Xanthine, and Hypoxanthine Using CoFe<sub>2</sub>O<sub>4</sub>/Reduced Graphene Oxide-Modified Electrode 

Journal of Nanomaterials

Simultaneous Voltammetric Determination of Uric Acid, Xanthine, and Hypoxanthine Using CoFe2O4/Reduced Graphene Oxide-Modified Electrode

Figure 10

Simultaneous Voltammetric Determination of Uric Acid, Xanthine, and Hypoxanthine Using CoFe₂O₄/Reduced Graphene Oxide-Modified Electrode