Effect of natural phosphate to remove silver interference in the detection of mercury(II) in aquatic algae and seawater samples

•The silver was impregnated onto natural phosphate (Ag/NP) using solid reaction.•The Ag/NP was used to determine mercury(II) without silver interferences.•The effect of experimental variables was investigated using square wave voltammetry.•The Ag/NP-CPE was investigated to determine mercury in aquatic algae and seawater samples.

A silver particles impregnated onto natural phosphate (Ag/NP) was synthesized using reaction in solid state. The obtained powder was characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The (Ag/NP) was used as modifier of carbon paste electrode (CPE) to determine mercury by square wave voltammetry. The calibration graph obtained is linear from 1.0 × 10− 8 mol·L− 1 to 1.0 × 10− 5 mol·L− 1 at preconcentration time of 5 min, percentage loading of 7%, with correlation coefficient of 0.993. The limits of detection (DL,3σ) and quantification (QL,10σ) were 5.8 × 10− 9 mol·L− 1 and 19.56 × 10− 9 mol·L− 1 respectively. The repeatability of the method expressed as relative standard deviation (R.S.D.) is 2.1% (n = 8). The proposed method was successfully applied to determine mercury(II) in aquatic algae and seawater samples.