فهرست نشریات علمی دسترسی آزاد ایران

The problem of heavy metal pollution of safe drinking water in Iraq is becoming an issue, especially by industrial and agricultural discharges, which are not regulated. This paper presents the logical conception, preparation, and complete analytical validation of a novel electrochemical sensor composed of a graphene oxide-gold nanocomposite (GOAuNC) to determine the presence of lead (Pb2+) and cadmium (Cd2+) in real water matrices with a combination of ultrasensitivity. SEM, XRD, and FTIR were used to determine the characteristics of the nanocomposite, which proved that gold nanoparticles (2030nm) were successfully integrated onto the sheets of graphene oxide. The sensor was made by drop-casting GO AuNC on screen-printed carbon electrodes (SPCES) to allow well-separated Pb2+ and Cd2+ differential pulse voltammetry (DPV) responses at voltages of -0.58 V and -0.82 V respectively. The process showed linearity between 0.1 and 50 0g/L of both metals, and the detection limits (0.032 0g/L of Pb2+ and 0.041 0g/L of Cd2+) were very low, far below WHO standards. The sensor was highly selective (against common interferents Ca2+, Mg2+, Zn2+, Cu2+), sensitive (96.3-103.7 percent spike recoveries), and reproducible (RSD 4.2 per cent). The sensor observed Pb2+ and Cd2+ in 73 and 64 samples of 42 water samples of Baghdad Governorate, respectively, with the highest contamination levels being observed at industrial sites. The outcomes were found to be very close to inductively coupled plasma mass spectrometry (ICP-MS) (r 2 = 0.994). Its portability, low cost (< $5/test), real-time analysis (less than 10 min) and strong performance in the field conditions makes this sensor an effective, field-deployable system to monitor water quality in Iraq and other low-resource locations at decentralized levels, which is directly related to Sustainable Development Goal 3 (Good Health and Well-being).