Spectrophotometric determination of dithizone–mercury complex by solid phase microextraction in micropipette tip syringe packed with activated carbon xerogel

• Hg (II) is determined in water samples in the range 30–280 μg L− 1.
• The analytical method developed for Hg (II) has a detection limit of 7.8 μg L− 1.
• The sample volume is an important advantage of the developed method.

A new simple miniaturized solid phase microextraction system in a syringe was developed for mercury (Hg) preconcentration of in water samples based on the adsorption of its dithizone complex on a microcolumn. The syringe system contains a micropipette tip packed with activated carbon xerogel. The influence of acidity, eluting agents, amount of adsorbent, complex stability and interfering ions was studied in detail. The complex retained on activated carbon xerogel in the micropipette tip–syringe system could be eluted using ethanol and the concentration was determined by visible spectrophotometry.The method showed good linearity in the range of 30–280 μg L− 1, with a limit of detection of 7.6 μg L− 1. The relative standard deviation (RSD%) for six replicate measurements of 280 μg L− 1 of Hg2 + ion was 1.36%.The proposed method was successfully applied to quantitative determination of Hg2 + in ground water and mineral water with satisfactory results.