Synthesis of a Pb(II) Photoresponsive Probe and Its Application to the Rapid Determination of Pb(II) in Mustard Samples

Lead ions in food can accumulate in the human body, leading to various diseases, so it is necessary to detect the content of lead ions in food. In this paper, a new Schiff base was prepared using derivatives of isophthalic acid and salicylaldehyde as a photoresponsive probe for Pb(II) ions. The Schiff base probe had an absorption peak at 505 nm after the addition of Pb(II) ions to an acetonitrile solution. However, other inorganic ions caused only slight absorbance changes at 505 nm. Based on this, a visible light analysis method for Pb(II) ions was established. The equilibrium time of the Schiff base probe with Pb(II) ions was 5 min, with a linear range of 2.5–25 ppm. The Schiff base probe was used to detect Pb(II) ion content in mustard samples, and the recoveries were over 90%. The detection results were not significantly different from those of the standard method, indicating that the Schiff base probe can be used for the rapid determination of Pb(II) ion content in real samples.