Sequential extraction--spectrofluorometric determination of lead and cadmium using cryptands

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Accurate determination of ultratrace heavy metals like lead and cadmium is crucial for environmental monitoring and public health.
• Existing methods may lack sensitivity or require complex sample preparation for ultratrace analysis.

Purpose of the Study:

• To develop and validate a sensitive spectrofluorimetric method for the simultaneous determination of ultratrace lead and cadmium.
• To apply the developed method for analyzing lead and cadmium in real-world samples such as zinc metals and soft drinks.

Main Methods:

• Sequential extraction of ternary ion-association complexes formed between metal cations (lead, cadmium), a cryptand ligand, and eosin as a counter ion.
• Spectrofluorimetric detection of the extracted complexes.
• Method validation including linearity, detection limits, and relative standard deviation.

Main Results:

• A linear working range was established from 0.5 ng/mL to 250 ng/mL for lead and 0.5 ng/mL to 150 ng/mL for cadmium.
• The relative standard deviation for the method was found to be 2-4%.
• Successful application of the method for determining lead and cadmium in zinc metals and soft drinks.

Conclusions:

• The proposed spectrofluorimetric method is highly sensitive and accurate for determining ultratrace amounts of lead and cadmium.
• The method's applicability to real samples demonstrates its practical value in environmental and food safety analysis.