Paper Strip and Ceramic Potentiometric Platforms Modified with Nano-Sized Polyaniline (PANi) for Static and Hydrodynamic Monitoring of Chromium in Industrial Samples

Abstract

Screen-printed membrane sensors based on the use of paper and ceramic substrates are fabricated, characterized, and used for rapid batch and continuous monitoring of CrIII in the form of CrO42− in some industrial products and wastewater samples. Strips of paper and ceramic platforms (15 × 5 mm) were covered with conductive carbon paint and then modified with polyaniline (PANI) film, to act as an ion-to-electron transducer, followed by a drop casting of plasticized poly (vinyl chloride) (PVC) Rhodamine-B chromate membrane as a recognition sensing material. In a 5.0 mmol L−1 Trizma buffer solution of pH ~8, the fabricated paper and ceramic based membrane sensors exhibited a near Nernstian response for CrVI ion with slopes of −29.7 ± 0.5 and −28.6 ± 0.3 mV decade−1, limit of detection 2.5 × 10−5 and 2.4 × 10−6 mol L−1 (1.3–0.12 µg mL−1), and linear concentration range 7.5 × 10−3–5.0 × 10−5 and 7.5 × 10−3–1.0 × 10−5 mol L−1 (390-0.5 µg mL−1), respectively. Both sensors exhibited fast and stable potentiometric response, excellent reproducibility, and good selectivity with respect to a number of common foreign inorganic species. Impedance spectroscopy and chronopotentiometry data revealed a small resistance and a larger double layer capacitance due to the presence of the intermediate polyaniline (PAN) conductive layer. Furthermore, the formation of a water layer between the ion selective membrane (ISM) and the underlying conductor polymer and between the conducting polymer and the carbon conducting surface was greatly reduced. The developed disposable solid-contact potentiometric sensors offer the advantages of simple design, long term potential stability, flexibility, miniaturization ability, short conditioning time, and cost effectiveness that enable mass production. The sensors were successfully used for static and hydrodynamic measurements of total chromium in some leather tanning wastewater and nickel-chrome alloy samples. The results compare favorably with data obtained by atomic absorption spectrometry.

Heavy Metals Detection with Paper-Based Electrochemical Sensors

“…95 In Hassan et al's research, polyaniline with high hydrophobicity was deposited between carbon printed paper strips and the ISM. 96 Both works demonstrated successful prevention of water layer formation due to the lipophilic conducting polymers. In addition to hydrophobic solid contacts, paper-strip ISEs with LDL of 1.2 nM for Cd 2+ were reported when an ISM with a lower coefficient of diffusion (MMA-DMA) than the conventional plasticized polyvinyl chloride was used.…”

“…Subsequently, highly lipophilic conducting polymer poly­(3-octylthiophene) was inserted between the gold layer and ISM . In Hassan et al’s research, polyaniline with high hydrophobicity was deposited between carbon printed paper strips and the ISM . Both works demonstrated successful prevention of water layer formation due to the lipophilic conducting polymers.…”

Chromium measurement in pharmaceutical samples: a comparative study of three new membrane electrodes with different electron-ion exchangers

“…Potentiometric membrane electrodes are suitable for analysis of different species as a result of their simplicity. [1][2][3][4][5][6][7][8] Considering the method for immobilizing the polymeric membrane over the electrode, various kinds of electrodes can be created such as coated wire ion selective electrodes (CW-ISEs), ion selective electrodes with liquid internal electrolyte (LIE-ISEs), and solidstate ion selective electrodes (SS-ISEs). An internal reference electrode is required in an LIE-ISE along with internal lling solution.…”

“…10 Thus, various analytical approaches have been established for chromium detection like inductively coupled plasma-atomic emission spectroscopy, Xray uorescence, atomic absorption spectroscopy, spectrophotometry, voltammetry [11][12][13][14][15][16][17] and potentiometric measurements based on ion-selective electrodes. 5,9,[18][19][20][21][22][23][24][25][26][27] Although these approaches have good sensitivity, they have disadvantages such as the high cost of routine analysis as well as tedious and time-consuming sample preparation procedure. However, several advantages are presented by the potentiometric measurements with the selective sensor including easy sampling conditions, simplicity of equipment, low cost, low limit of detection, and the relatively wide linearity range of concentration in different solutions.…”

Paper-based solution sampling coupled with potentiometric ion sensors

“…In an all-integrating paper-based potentiometric setup, paper serves not only as a microfluidic sampling substrate, but also as a mechanical support for deposition of electrodes as well as the formation of sampling/detection and other functional zones depending on its design, thereby is further denoted as a paper platform. Paper-based micro electrodes are either designed as individual ISEs [115][116][117][118][119] and REs [120,121] or integrated in miniaturised potentiometric paper-based platforms [88,95,98,[122][123][124][125][126][127][128][129][130]. The development of all-integrating paper-based sensors are as portable and disposable tools for on-site ion determination of clinical/health [95,98,[128][129][130], environmental [95,124,131] and foodstuff [124,126] samples.…”