Rapid Determination of Cadmium in Rice by Immunochromatography Using Anti-(Cd-EDTA) Antibody Labeled with Gold Particle

Simplified method for determining cadmium concentrations in rice foliage and soil by using a biosensor kit with immunochromatography

“…Figure 1 shows the principle of immunochromatography applied to the detection of Cd 2, 3. An anti‐Cd–EDTA monoclonal antibody, obtained from mice immunized with Cd–EDTA, is labeled with gold colloid to make it visible to the naked eye.…”

“…The extract (rice foliage and soil) was filtered with filter paper, and 5 mL of the filtrate was applied to a chelate column where Cd was trapped selectively; the column was then washed with 5 mL of 0.1 mol L −1 HCl solution to remove any other metals, because Mn–EDTA, Zn–EDTA, and Cu–EDTA have a small degree of cross‐reactivity to the anti‐Cd–EDTA antibody and interfere with the immunochromatography 3. Cadmium retained in the column was eluted with 5 mL of 0.05 mol L −1 HNO 3 .…”

“…Recently, an immunochromatographic assay kit for detecting Cd in brown rice was manufactured by Kansai Electric Power Co. of Japan 2, 3. This sensor kit uses the antigen–antibody complex reaction between the Cd–EDTA complex and an anti‐Cd–EDTA antibody that reacts specifically with this complex to detect Cd at concentrations of 0.01 mg L −1 or higher; the kit shows the results in terms of the degree of color developed on a test paper.…”

“…Because the antigen–antibody complex reaction is quantitative, it should be possible to determine the degree of color development by using a color‐reading device and thereby to estimate the concentration of the analyte by comparing the color developed with that produced by a standardized reference solution. We have already used the immunochromatographic assay kit for the successful determination of Cd concentrations in brown rice with respect of an international standard, 0.4 mg kg −1 3. This method does not require the services of analytical experts or the use of expensive analytical equipment; the test can be performed with apparatus commonly found in chemical laboratories.…”

Surface plasmon resonance based competitive immunoassay for Cd2+

“…At present, all antibodies specic for cadmium recognize a chelated form of Cd 2+ , that is, Cd-EDTA. [25][26][27][28][29] In our previous study, cadmium ion was respectively coupled to carrier protein (bovine serum albumin, BSA; ovalbumin, OVA) via a phenyl isothiocyanate-EDTA (ITCBE) to form the immunogen (Cd-ITCBE-BSA) and coating antigen (Cd-ITCBE-OVA). Using the hybridoma technique we successfully produced monoclonal antibody (mAb) against Cd 2+ , which were then characterized by an indirect competitive enzyme linked immunosorbent assay (ELISA).…”