Abstract:

Copper colloids were synthesized in ethylene glycol by using ascorbic acid(VC) as the reducing agent and polyvinyl pyrrolidone(PVP) as the dispersant. The as-prepared copper colloids were characterized by XRD, UV-Vis and resonance light scattering（RLS）. Face-centered cubic Cu(0) particles were formed, which displayed resonance light scattering(RLS) spectra with a typical plasma resonance absorption within the range of 592~602 nm and the maximum scattering wavelength at 468 nm. The RLS results show that the favorable reaction conditions are in the addition order of VC, CuSO4 and PVP under n(VC)/n(Cu2+)=15, n(PVP-K30)/n(Cu2+)=1.4, temperature=60 ℃, and incubating for 1 h. The obtained copper colloids are stable for 24 h. Under such reaction conditions, the scattering intensity(ΔIRLS) is proportional to Cu2+ content in the range of 5.12~12.8 mg/L with the detection limit of 0.63 μg/L(3σ), and the regression equation is ΔI=7.4202ρ-631.8(r=0.9962). When the concentration of Cu2+ solution is 10 mg/L, the colloidal system is stable for 24 h. Foreign substances such as 0.64 mg/L MnSO4, CdSO4 and ZnSO4, 1.28 mg/L of KI, 64 mg/L of Na2CO3 and Ca(OH)2, 960 mg/L CH3CH2OH, 640 mg/L CH3OH and 320 mg/L CH3CH2CH2OH had no interference. Therefore, a simple method to detect the Cu2+ in ethylene glycol is established using the RLS spectra.

Key words: copper colloids, resonance light scattering, ascorbic acid