Preconcentration and Determination of Metal Ions Using Fluorescein-Modified Silica Gel and Inductively Coupled Plasma-Optical Emission Spectrometry

ABSTRACT

A new fluorescein modified silica gel was utilized for solid-phase extraction for the simultaneous and selective preconcentrations of Ba²⁺, Cd²⁺, Co²⁺, Cu²⁺, Mn²⁺, Ni²⁺, Pb²⁺, and Sr²⁺ prior to determination by inductively coupled plasma-optical emission spectrometry. The sorbent was characterized using X-ray diffraction and scanning electron microscopy. The optimum conditions were 25.0 mL of sample at pH 5.0 and a 3.0 mL min⁻¹ flow rate. The ions were desorbed with 3.0 mL of 0.5 mol L⁻¹ HNO₃ at 3.0 mL min⁻¹. The relative standard deviations were below 5%, and the limits of detection were between 11.5 and 152.0 ng L⁻¹. The preconcentration factor was 8.3 for Sr²⁺ and 333.3 for Ba²⁺, Cd²⁺, Co²⁺, Cu²⁺, Mn²⁺, Ni²⁺, and Pb²⁺. The uptake capacity of the sorbent was between 0.29 and 1.25 mg g⁻¹. The accuracy was assessed by analyzing water certified reference materials. The recoveries for the standard reference materials were between 92.5 and 102.9% except for Sr²⁺. The method was used for the analysis of natural water samples.

KEYWORDS:

• Fluorescein
• inductively coupled plasma-optical emission spectrometry (ICP-OES)
• preconcentration
• solid-phase extraction
• water analysis

Acknowledgment

The authors wish to express their deep thanks to Science and Technology Research and Application Center of Balıkesir University for technical support.