title: Screen-printed carbon electrodes modified with cobalt phthalocyanine for selective sulfur detection in cosmetic products.
abstract: Cobalt phthalocyanine (CoPc) films were deposited on the surface of a screen-printed carbon electrode using a simple drop coating method. The cyclic voltammogram of the resulting CoPc modified screen-printed electrode (CoPc/SPE) prepared under optimum conditions shows a well-behaved redox couple due to the (Co(I)/Co(II)) system. The CoPc/SPE surface demonstrates excellent electrochemical activity towards the oxidation of sulfur in a 0.01 mol·L(-1) NaOH. A linear calibration curve with the detection limit (D(L), S/N = 3) of 0.325 mg·L(-1) was achieved by CoPc/SPE coupled with flow injection analysis of the sulfur concentration ranging from 4 to 1120 mg·L(-1). The precision of the system response was evaluated (3.60% and 3.52% RSD for 12 repeated injections), in the range of 64 and 480 mg·L(-1) sulfur. The applicability of the method was successfully demonstrated in a real sample analysis of sulfur in anti-acne creams, and good recovery was obtained. The CoPc/SPE displayed several advantages in sulfur determination including easy fabrication, high stability, and low cost.
authors: Department of Cosmetic Science, Providence University 200 Chungchi Rd., Taichung 43301, Taiwan; E-Mails: pychen2@pu.edu.tw (P.-Y.C.); s9624065@pu.edu.tw (M.-C.C.); tftsay@pu.edu.tw (F.-J.T.); nfchang@pu.edu.tw (N.-F.C.).
authors: Pei-Yen
authors: PY
authors: Chen
authors: Chin-Hsiang
authors: CH
authors: Luo
authors: Mei-Chin
authors: MC
authors: Chen
authors: Feng-Jie
authors: FJ
authors: Tsai
authors: Nai-Fang
authors: NF
authors: Chang
authors: Ying
authors: Y
authors: Shih
mesh_terms: D002244:Carbon / Q000737:chemistry; D003358:Cosmetics / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D017022:Flow Injection Analysis; D007211:Indoles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D013455:Sulfur / Q000032:analysis*
chemical_list: D003358:Cosmetics; D007211:Indoles; D009942:Organometallic Compounds; C063633:cobalt phthalocyanine; D013455:Sulfur; D002244:Carbon