Section: Oil refining and petroleum chemistry

UOT: 665.6/.7

DOI: 10.37474/0365-8554/2020-2-55-59

New simple spectrophotometric method for the specification of silver (i) in oil-water samples

A simple, highly selective and non-extractive spectrophotometric method for the specification of trace amounts silver (I) has been developed. In the water media 2,2’-di (2,3,4-trihydroxy-phenylazo) biphenyl reacts with the silver to give a highly absorbent greenish-yellow chelate in a molar ratio 2:1 (Ag:R). The reaction is instantaneous, the maximum absorption was obtained at 540 nm and remains stable for 24 hours. The average molar absorptivity and Sandell’s sensitivity were 4.3×104 l mol-1 cm-1 and 5.0 mkg cm-2 of silver (I), respectively. Linear calibration graphs were obtained for 0.1–30 mkgml−1 of silver (I), respectively. A large excess of over 30 cations, anions and complex agents do not interfere in the specification. The method is highly selective for silver and was successfully appliedin a number of oilwater samples. It has high precision and accuracy (s = ± 0.01 for 0.5 mkgl-1). Therefore, it may be used for monitoring to establish trace level of silver (I) in difficult matrices of oilwater samples.