Biomimetic sensor based on a novel copper complex for the determination of hydroquinone in cosmetics

Abstract A new dinuclear copper(II) complex [Cu 2 (HL)(OAc)](ClO 4 ) 2 containing a novel ligand, N,N′,N′ -[tris-(2-pyridylmethyl)]- N -(2-hydroxy-3,5-di- tert -butylbenzyl)-1,3-propanediamine-2-ol (H 2 L) as a catechol oxidase catalyst, was synthesized, characterized and used in the construction of a biomimetic sensor for determining hydroquinone in cosmetics by square wave voltammetry. The hydroquinone is oxidized to quinone and the electrochemical reduction back to hydroquinone was obtained at −0.2 V versus Ag/AgCl. Several parameters were investigated to evaluate the performance of the biomimetic sensor obtained after the incorporation of the copper(II) complex in a carbon paste. The responses under optimized conditions were obtained in a 0.1 mol L −1 phosphate buffer solution (pH 7.5), 10:15:75% (w/w/w) of the copper(II) complex:nujol:graphite powder and the calibration curve was linear for hydroquinone concentrations from 6.0 × 10 −5 to 2.5 × 10 −3  mol L −1 ( r  = 0.9995). The detection and quantification limit was 3.0 × 10 −7  mol L −1 and 1.0 × 10 −6  mol L −1 , respectively. The recovery of hydroquinone from two samples ranged from 94.2 to 103.5% and the relative standard deviation was less than 1.0% for a solution containing 1.0 × 10 −3  mol L −1 hydroquinone ( n  = 8). The lifetime of this biosensor was 7 months (at least 750 determinations). Results obtained for hydroquinone in cosmetics using the proposed biomimetic sensor and those obtained by the official method are in agreement at the 95% confidence level.

[1]  O. Fatibello‐Filho,et al.  Jack Fruit‐Capric Acid Biosensor for Total Phenols Determination in Wastewaters , 2004 .

[2]  I. Vieira,et al.  Development of a biosensor based on gilo peroxidase immobilized on chitosan chemically crosslinked with epichlorohydrin for determination of rutin. , 2006, Journal of pharmaceutical and biomedical analysis.

[3]  J. Firth,et al.  Determination of hydroquinone in skin-toning creams using high-performance liquid chromatography. , 1986, The Analyst.

[4]  E. Camera,et al.  Chemical and instrumental approaches to treat hyperpigmentation. , 2003, Pigment cell research.

[5]  M. Giorgi,et al.  Catechol oxidase activity of dicopper complexes with N-donor ligands , 2003 .

[6]  E. Solomon,et al.  Multicopper Oxidases and Oxygenases. , 1996, Chemical reviews.

[7]  Jean-Michel Kauffmann,et al.  Sensors based on carbon paste in electrochemical analysis: A review with particular emphasis on the period 1990–1993 , 1995 .

[8]  R. Adams.  Carbon Paste Electrodes , 1958 .

[9]  B. Krebs,et al.  Structural and functional studies on model compounds of purple acid phosphatases and catechol oxidases , 1999 .

[10]  Fortunato Sevilla,et al.  Biomimetic properties and surface studies of a piezoelectric caffeine sensor based on electrosynthesized polypyrrole. , 2005, Talanta.

[11]  Lai-Hao Wang.  Simultaneous determination of hydroquinone ethers in cosmetics after preconcentration at a carbon paste electrode , 1995 .

[12]  O. Fatibello‐Filho,et al.  Chronoamperometric determination of paracetamol using an avocado tissue (Persea americana) biosensor. , 2001, Talanta.

[13]  L. Kubota,et al.  Development of an amperometric sensor for phenol compounds using a Nafion † membrane doped with copper dipyridyl complex as a biomimetic catalyst , 2002 .

[14]  L. Goeyens,et al.  Experimental and statistical validation of HPLC analysis of hydroquinone and its 4-methoxyphenol, 4-ethoxyphenol and 4-benzyloxyphenol ethers in cosmetic products , 1999 .

[15]  A. Mangrich,et al.  A new dinuclear unsymmetric copper(II) complex as model for the active site of catechol oxidase , 2001 .

[16]  C. Belle,et al.  Asymmetry in Bridged Binuclear Metalloenzymes: Lessons for the Chemist , 2003 .

[17]  L. Rossi,et al.  Synthesis, Structure, Physicochemical Properties and Catecholase-like Activity of a New Dicopper(II) Complex , 2001 .

[18]  L. Rossi,et al.  Catecholase activity of a series of dicopper(II) complexes with variable Cu-OH(phenol) moieties. , 2002, Inorganic chemistry.

[19]  Lauro T. Kubota,et al.  Tris (2,2′-bipyridil) copper (II) chloride complex: a biomimetic tyrosinase catalyst in the amperometric sensor construction , 2003 .

[20]  I. Vieira,et al.  Immobilization procedures for the development of a biosensor for determination of hydroquinone using chitosan and gilo (Solanum gilo) , 2006 .

[21]  J. Sacchettini,et al.  Catechol oxidase - structure and activity. , 1999, Current opinion in structural biology.

[22]  W. Haase,et al.  A new N,O-donor binucleating ligand and its first iron(III) complex as a model for the purple acid phosphatases , 1992 .

[23]  O. Fatibello‐Filho,et al.  L-ascorbic acid determination in pharmaceutical formulations using a biosensor based on carbon paste modified with crude extract of zucchini (Cucurbita pepo) , 2000 .

[24]  O. Fatibello‐Filho,et al.  Biosensor based on paraffin/graphite modified with sweet potato tissue for the determination of hydroquinone in cosmetic cream in organic phase. , 2000, Talanta.

[25]  M. Laranjeira,et al.  Biosensor Based on Chitosan Biopolymer and Crude Extract of Ginger (Zingiber officinales Rosc.) for the Determination of Hydroquinone in Wastewater of Photographic Process , 2004 .

[26]  A. Mangrich,et al.  Synthesis, characterization and structure of a new zinc(II) complex containing the hexadentate N,N′,N,N′-bis[(2-hydroxy-3,5-di-tert-butylbenzyl)(2-pyridylmethyl)]-ethylenediamine ligand: Generation of phenoxyl radical species , 2005 .

[27]  N. A. M. Eskin,et al.  Oxidative enzymes in foods. , 1991 .