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4-Methoxy-Ortho -Phthalaldehyde: a Promising Derivatizing Agent for the Fluorimetric Evaluation of Histamine in Seafood

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4-Methoxy-Ortho -Phthalaldehyde: a Promising Derivatizing Agent for the Fluorimetric Evaluation of Histamine in Seafood 4-Methoxy-ortho -phthalaldehyde: a promising derivatizing agent for the fluorimetric evaluation of histamine in seafood Clémence Moitessier, Khémesse Kital, Pierre-Edouard Danjou, Francine Cazier-Dennin To cite this version: Clémence Moitessier, Khémesse Kital, Pierre-Edouard Danjou, Francine Cazier-Dennin. 4-Methoxy- ortho -phthalaldehyde: a promising derivatizing agent for the fluorimetric evaluation of histamine in seafood. Talanta Open, 2020, 2, 10.1016/j.talo.2020.100014. hal-02942358 HAL Id: hal-02942358 https://hal.archives-ouvertes.fr/hal-02942358 Submitted on 17 Sep 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Talanta Open 2 (2020) 100014 Contents lists available at ScienceDirect Talanta Open journal homepage: www.elsevier.com/locate/talo Full Length Article 4-Methoxy- ortho -phthalaldehyde: a promising derivatizing agent for the fluorimetric evaluation of histamine in seafood Clémence Moitessier a, Khémesse Kital a,b, Pierre-Edouard Danjou a,∗, Francine Cazier-Dennin a,∗ a Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV) - Université du Littoral Côte d’Opale, 145 Avenue Maurice Schumann, MREI 1, 59140 Dunkerque, France b Laboratoire de Photochimie et d’Analyse (LPA), Faculté des Sciences et Techniques, Université Cheikh Anta Diop, BP 5005 Dakar- Sénégal a r t i c l e i n f o a b s t r a c t Keywords: Histamine, the molecule associated with food poisoning, is nowadays considered as a reliable marker of seafood Biogenic amines freshness and therefore its rapid and easy quantification appears critical. Existing method like HPLC or direct Histamine fluorimetric analysis fluorimetric analysis employing ortho -phthalaldehyde (OPA) can be time-consuming and tedious. To overcome Molecular fluorescence spectroscopy this problem, we propose in this paper to evaluate the application potential of 4-methoxy- ortho -phthalaldehyde 4-methoxy- ortho -phthalaldehyde (MO-OPA) for the rapid and easy evaluation of histamine in seafood samples. For this purpose, the histamine com- plexation conditions were studied by molecular fluorescence spectroscopy using MO-OPA as derivatization agent and then compared with the reference compounds: OPA. MOPA proved to be superior to OPA for histamine detec- tion in terms of linearity range (1.10 −6–1.10 −4 mol.L −1, R 2> 0.99, n = 10) and detection limit (9.5.10 −7 mol.L −1). The optimal conditions were next applied to the analysis of histamine in a mixture of biogenic amines standards and finally on real samples of yellowfin tuna of known histamine concentration. Introduction analysis is also a commonly employed technique [26–28] especially the one developed by the AOAC which is currently approved by the Food safety and quality are increasingly at the center of preoccupa- FDA [7 , 29 , 30] . Since HA does not contain any fluorophore moiety, tion for consumers as well as health agencies. Consequently, a perma- a derivatization procedure is crucial in order to allow an analysis by nent evaluation of the freshness and toxicity index of foods is required molecular fluorescence spectroscopy. Several derivatizing agents have and involves in particular the characterization of spoilage markers such been employed and the most commonly used ones are dansyl chlo- as biogenic amines (BAs). In food, these non-volatile nitrogenous or- ride, [31 , 32] fluorescamine, [33 , 34] 2,3-naphthalenedicarboxaldehyde ganic bases result from the decarboxylation of their amino acids pre- [35 , 36] and ortho -phthalaldehyde (OPA). [29 , 37–39 ] Employed since cursors generated by pathogenic microorganisms as well as by matu- 1959, [40] the OPA takes the lead over other reagents since it enables ration and fermentation processes. [1 , 2] While BAs are essential com- the detection of BA at low concentrations and without HPLC separation. ponents in the process aiming to regulate physiological functions in The selectivity over other aminated compounds is achieved through the human body, they can also pose a serious risk to the consumers the specific excitation and emission wavelengths of each BA/OPA com- health due to their relatively low toxic threshold. [3–5] Detection and plexes. [41] Nevertheless, OPA derivatization leads to poorly stable quantification studies of BAs are extensively illustrated in the litera- compounds. The addition of thiol reagents such as 2-mercaptoethanol, ture, particularly those addressing histamine (HA). Indeed, the pres- [42] 3-mercaptopropionic acid [42 , 43] or N-acetylcysteine [42 , 43] was ence of HA in seafood is regulated by health authorities like the Euro- proposed in order to create less unstable OPA/thiol/HA complexes, to pean Commission [6] or the U.S. Food and Drug Administration (FDA) extend the pH range required for the formation of compounds as well [7] since it is responsible for histamine intoxication. Currently, other as to facilitate its applicability. With a similar aim, we propose here BAs such as putrescine and cadaverine are also studied considering that to study the behavior of HA fluorescent analysis of a new derivatization they can potentiate the toxic effect of HA. [8] As a result of its tox- agent possessing a methoxy group directly linked to the aromatic core of icity and regulation, HA analysis techniques are widely documented, the OPA: 4-methoxy- ortho -phthalaldehyde (MO-OPA) ( Fig. 1 ). As far as including colorimetric, [9–11] enzymatic [12 , 13] , electrochemical [14– literature is concerned, derivatives based on an OPA core have scarcely 16] and chromatographic methods [17–25]. Fluorescence spectroscopy been used as derivatization agents and were never applied to BAs ∗ Corresponding authors. E-mail addresses: [email protected] (P.-E. Danjou), [email protected] (F. Cazier-Dennin). https://doi.org/10.1016/j.talo.2020.100014 Received 29 June 2020; Received in revised form 4 September 2020; Accepted 4 September 2020 2666-8319/© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) C. Moitessier, K. Kital and P.-E. Danjou et al. Talanta Open 2 (2020) 100014 Fig. 1. The chemical structures of ortho -phthalaldehyde and 4-methoxy- ortho -phthalaldehyde (left) and biogenic amines (right) used in this study. analysis. In a recent report, Zhang et all. [44 , 45] proposed a synthetic Procedures route to MO-OPA and 4,5-dimethoxy- ortho -phthalaldehyde to achieve a fluorescence probe for ammonium traces detection with the successful Solution preparation development of a hand-held portable fluorometer. They report that the Stock solutions of HA (1.10 −2 mol.L −1 ) and derivatization agent addition of an electron-donating group allows to increase the electron (OPA or MO-OPA; 1.10 −2 mol.L −1 ) were prepared by dissolving the density of the aromatic core leading to an enhancement of the fluores- compounds in water. Serial dilutions were performed to obtain working cence intensity. Moreover, it enables faster reaction with analytes at standard solutions. All solutions were protected against light and stored room temperature. [44] In this paper, we take advantage of our prece- at 4°C prior to use unless specified. The shelf-life of the solutions must dent expertise on MO-OPA synthesis [46] to evaluate its efficiency on not exceed one week. [29] BAs and derivatization agent were mixed HA fluorescent analysis. To fulfill this goal, the complexation condi- during the final dilutions prior to fluorimetric analysis. The solutions tions of HA with MO-OPA as well as the molecular fluorescent param- were degassed in an ultrasonic bath during their preparation and before eters were investigated and then properties of MO-OPA as derivatiza- the recording of molecular fluorescence spectra. tion agent were compared with standard OPA. These optimal conditions were next applied to the fluorimetric analysis of HA with MO-OPA in Analytical measurements a mixture of BAs standards and finally on real yellowfin tuna ( Thunnus For the fluorimetric method, the fluorescence intensity was moni- albacares ) samples. tored at the fixed analytical excitation ( ex ) and emission ( em ) wave- lengths of the complexes. Linear calibration curves were obtained at Experimental section these ex and em values by measuring the spectra height signal. All flu- orescence measurements were corrected for the solvent signal with the Reagents appropriate blank. All the chemicals were purchased from Acros Organic or Sigma- Aldrich and were used as received without further purification unless Fish samples preparation specified. Biogenic amines were purchased as: Agmatine sulfate salt Two tuna cans of known level of HA (15.79 ± 2.53 mg/kg and ( ≥ 97%), cadaverine dihydrochloride ( ≥ 99%), histamine dihydrochlo- 148.64 ± 7.99 mg/kg) were processed according to a modified proce- ride ( ≥ 99%), putrescine dihydrochloride ( ≥ 99%), spermidine trihy- dure based on Bjornsdottir–Butter et al. [30] work. Briefly, methanol drochloride ( ≥ 99%), ortho -phthalaldehyde ( ≥ 99%; recrystallized from (75% v/v; 50 mL) was added to 10 g of tuna and the mixture was vig- n-hexane). 4-methoxy- ortho -phthalaldehyde (MO-OPA) was synthesized orously stirred during 30 min. The sample was then filtered over fritted according to the procedure of Moitessier et al. [46] glass, evaporated and put back in solution in HPLC grade water. The HPLC grade water was used throughout the study for the preparation aqueous sample was transferred into a 50 mL volumetric flask and com- of analytical solutions. The pH was adjusted using sodium hydroxide 1M pleted with water. 1 mL of the resulting solution was diluted with wa- or hydrochloric acid 1% aqueous solutions.
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