Abstract:

Rapid extraction methods for heavy metals (Cu, Pb, and Cd) with dilute acids (HCl, HNO3, and H2SO4) were
investigated and established in the determination of aquatic products (Ostrea rivularis, Perna viridis and Metapenaeus
ensi). The results showed that the optimal extraction concentration was 2 mol/L for the three dilute acids. Besides, the
optimal extraction time and temperature were 10 min and 20–90 ℃, 10 min and 10–90 ℃, 15 min and 10–90 ℃ for HCl,
H2SO4 and HNO3, respectively. Compared with the microwave digestion method, the extraction efficiencies of the heavy
metals Cu, Pb, and Cd with these three dilute acids followed the decreasing order: HNO3, H2SO4 and HCl. The spiked
recoveries of these heavy metals were 69%–97%, 97%–116% and 98%–111% for dilute solutions of HCl, H2SO4 and
HNO3, respectively. Together considering extraction time, temperature and spiked recovery, the extraction methods with
H2SO4 and HNO3 solution are feasible. Two groups of Cd concentrations, extracted from aquatic products by dilute acid
pretreatment method, were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and ELISA,
respectively. Linear regression demonstrated that the results from both analytical techniques were significantly correlated
(P ＜ 0.01). This shows that dilute acid pretreatment method could meet the requirements of ELISA assay for heavy metals
in aquatic products.

Key words: acid extraction, aquatic products, heavy metals, enzyme-linked immunosorbent assay (ELISA)