Cost-effective synthesis of three-dimensional nitrogen-doped nanostructured carbons with hierarchical architectures from the biomass of sea-tangle for the amperometric determination of ascorbic acid

Highlights

• Cost-effective synthesis of nitrogen-doped nanostructured carbons from sea-tangle.

• A sensitive and selective amperometric sensor for ascorbic acid detection.

• Detect the content of ascorbic acid in real samples with satisfactory results.

Abstract

In this work, the three-dimensional nitrogen-doped nanostructured carbons with hierarchical architectures (3D-NNCsHAs) with high density of defective sites, high surface area and pluralities of pore size distributions was prepared through the pyrolysis of sea-tangle (Laminaria japonica), an inexpensive, eco-friendly and abundant precursor. Benefitting from their structural uniqueness, a selective and sensitive ascorbic acid (AA) sensor based on 3D-NNCsHAs was developed. Compared to the glassy carbon electrode (GCE) and the carbon nanotubes modified GCE (CNTs/GCE), the 3D-NNCsHAs modified GCE (3D-NNCsHAs/GCE) presents higher performance towards the electrocatalysis and detection of AA, such as lower detection limit (1 μM), wider linear range (10–4410 μM) and lower electrooxidation peak potential (−0.02 V vs. Ag/AgCl). In addition, 3D-NNCsHAs/GCE also exhibits high anti-interference and anti-fouling abilities for AA detection. Particularly, the fabricated 3D-NNCsHAs/GCE is able to determine AA in real samples and the results acquired are satisfactory. Therefore, the 3D-NNCsHAs can be considered as a kind of novel electrode nanomaterial for the fabrication of selective and sensitive AA sensor for the extensive practical applications ranging from food analysis, to pharmaceutical industry and clinical test.

Introduction

As a vital antioxidant, the ascorbic acid (AA) has been commonly used in pharmaceuticals, cosmetics and food [1,2]. Meanwhile, the AA also takes part in several human physiological processes and is closely related to human health [2,3]. The lack of AA could cause several diseases and disorders, including Parkinson's disease, rheumatoid arthritis, cardiovascular disease and even cancer occurrence [2,3]. And the excess AA intake may result in urinary stones, diarrhea and stomach convulsions [4]. Therefore, the accurate AA detection is important for both industry and the human lives. Up to now, different techniques including spectrophotometry [5], solid phase iodine [6], chromatography [7], chemiluminescence [8] and electrochemical techniques [9] have been applied to detect AA. Among of these techniques, the electrochemistry based one with the attractive features of high sensitivity and relatively easy operation was considered to be capable for AA detection [9,10]. However, a high overvoltage for AA electrooxidation on traditional bare electrodes often results in fouling on sensing interface due to the absorbance of AA oxydate at the surface of electrodes, which would lead to low sensitivity, low selectivity and poor reproducibility [3,11]. To decrease the overpotential for AA electrooxidation, noble metal based electrodes were applied for electrochemical AA sensors with wide linear range and low detection limit [9,12]. However, the limited word-wide supply and the high costs of noble metals hinder their large-scale application [13]. The development of cost-effective, eco-friendly and excellent electrocatalysts for the detection of AA is imperative.

Nanomaterials are the nanoscaled materials that have at least one dimension in the 1–100 nm range, and compared with the materials in the bulk, the nanomaterials often exhibit superior performance [9,12,[14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27]]. Carbon nanomaterials, owing to wide potential window, inert chemical property and high electroanalysis performance for different analytes have been applied for electrochemical analysis [14,[28], [29], [30], [31], [32], [33], [34], [35]]. Many researchers have synthesized many kinds of carbon nanomaterials such as graphene [36], mesoporous carbons [37,38] and carbon nanotubes [39] as electrode modifiers to construct electrochemical sensors. In particular, due to nontoxicity, low cost and excellent chemical stability, the carbon nanomaterials derived from biomass (such as the waste of agriculture, industry, and urban life) have attracted a lot of attention to the development of electrochemical sensors [40,41]. For example, dead mango leaves was used to prepare carbon nanomaterial which demonstrated a low detection limit in the tests for cadmium and lead ions [42]. Owing to their adjustable pore size, the oxygen-containing functional groups and large surface area, the pumpkin stem derived activated carbon exhibited excellent electrochemical activity for AA, dopamine and uric acid, which also detected biomolecules in hemolymph obtained from the snail and the serum acquired from human [41]. Therefore, the low-cost biomass-derived carbon nanomaterials are attractive for the electroanalysis.

Herein, we fabricated a selective and sensitive amperometric AA sensor based on three-dimensional nitrogen-doped nanostructured carbons with hierarchical architectures (3D-NNCsHAs) which is synthesized through the direct carbonation of sea-tangle. For AA electrooxidation, the 3D-NNCsHAs modified GCE (3D-NNCsHAs/GCE) exhibits much lower overpotential compared to glassy carbon electrode (GCE) or carbon nanotubes (CNTs) modified GCE (CNTs/GCE). On the basis of the improved electrochemical activity, the 3D-NNCsHAs/GCE exhibits higher sensitivity, lower detection limit, wider linear range and better stability than CNTs/GCE for AA detection. Especially, the levels of AA in commercial AA injection and commercial beverage can be successfully determined by 3D-NNCsHAs/GCE.