Development of a new passive sampler based on diffusive milligel beads for copper analysis in water

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Accurate determination of free copper ion (Cu(2+)) concentration is crucial for water quality assessment.
• Existing methods may have limitations in passive sampling for free metal ions.
• Development of novel passive samplers is needed for efficient water monitoring.

Purpose of the Study:

• To design and characterize a new passive sampler for free copper ion determination in aqueous solutions.
• To synthesize and optimize diffusive milligel (DMG) beads incorporating cation exchange resin (Chelex).
• To evaluate the performance of the developed DMG samplers for copper ion absorption and quantification.

Main Methods:

• Synthesis of Chelex-incorporated milligel beads using a droplet-based millifluidic process.
• Characterization of milligel composition, pore size, and bead morphology (prolate spheroids).
• Determination of mass-transfer coefficient (k0) and sampler-water partition coefficient (Ksw) via static exposure.
• Development of a DMG bead digestion method coupled with Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES) for copper quantification.

Main Results:

• Successfully synthesized DMG beads with 7.5% and 15% Chelex content and 6 nm pore size.
• Demonstrated copper accumulation in DMG beads following Fick's first law of diffusion.
• Achieved accurate copper quantification with a mean recovery of 99% and repeatability of 7%.

Conclusions:

• The developed DMG passive samplers are effective for absorbing free copper ions from aqueous solutions.
• The optimized analytical method allows for accurate and repeatable quantification of absorbed copper.
• These DMG devices represent a promising tool for environmental water monitoring of copper.