FSTest Heavy Metal Cd Rapid Test Strip for Seafood (10 Tests)

Product Overview

The FSTest Heavy Metal Cd Rapid Test Strip for Seafood is a professional-grade, immuno-chromatographic assay designed for the fast, qualitative screening of heavy metal cadmium (Cd) contamination in marine and freshwater products. This kit provides seafood processors, aquaculture farms, and food quality testing laboratories with a streamlined, field-ready tool to audit raw materials and maintain strict compliance with global food safety regulations.

Tailored with distinct preparation protocols for both fish and shrimp matrices, this testing system effectively intercepts hazardous cadmium loads early in the supply chain, acting as a reliable first-line defense in corporate quality assurance programs.

Product Highlights & Key Benefits

· Swift On-Site Screening: Complete the immunochromatographic strip flow and interpret visual lines within a rapid 10 to 13-minute testing window.

· Species-Specific Detection Limits: Offers optimized regulatory cut-off limits precisely calibrated for different seafood types to match international safety standards: Fish Tissue (0.1 mg/kg) and Shrimp Tissue (0.5 mg/kg).

· Fully Self-Contained Kit Structure: Arrives fully packed with all necessary specialized extraction chemical agents (Reagents A, B, C), a Chelating Agent, pre-loaded microwells, and multi-size centrifuge tubes.

· Definite Inverse Visual Readout: Employs a competitive inhibition assay format where an increasing cadmium (Cd) concentration causes the Test (T) line to fade or completely disappear, ensuring straightforward interpretation without electronic readers.

· Robust Ambient Tolerance: Designed to react and deliver accurate results at standard room temperatures (20–40°C), with a long sealed shelf life at 4–30°C.

Technical Principle: Competitive Inhibition

The test is based on a competitive lateral flow immunochromatographic assay format. The strip features an area for result reading that contains a built-in Control (C) line and a Test (T) line, both of which remain completely invisible before sample fluidics activation.

Extracted Cadmium Ions (Cd) + Antibody-Conjugates → Lateral Flow → Inhibition of Binding at T-Line → Faded or Absent T-Line

When the prepared sample solution is applied, the liquid flows laterally upward across the strip surface via capillary action and reacts with pre-coated recombinant antigens. The intensity of the color on the T test line has an opposite correspondence with the cadmium (Cd) concentration in the sample. If cadmium is present at or above the threshold limit (0.1 mg/kg for fish or 0.5 mg/kg for shrimp), it binds to the antibodies and completely inhibits them from reacting with the antigens on the T-line. This causes the Test (T) line to become visibly lighter than the C-line or show no color at all. Conversely, a negative sample produces a strong, visible color band at the T zone. The Control (C) line always triggers to indicate a valid test run.

Specifications & Limit of Detection

Step-by-Step Procedure

1. Matrix-Specific Tissue Extraction

Ensure all reagents are matched to standard lab balances and centrifuges before processing.

· For Fish Samples:Homogenization: Take a representative fish tissue sample, completely remove the fat, and grind or homogenize thoroughly. Weigh exactly 2 g of the processed sample into a 15 mL centrifuge tube.

· Phase Separation: Add 0.8 mL of Heavy Metal Cd Reagent A and 3 mL of Heavy Metal Cd Reagent B. Cap tightly, fully stir and mix for 3 minutes, then centrifuge at 4000 rpm for 2 minutes.

· Reaction Mix (Key Step): Extract exactly 200 µL of the clear supernatant and transfer it into a clean 1.5 mL centrifuge tube. Add 30 µL of Heavy Metal Cd Chelating Agent and stir/mix well.

· Final Activation: Add exactly 15 µL of Heavy Metal Cd Reagent C, stir and mix thoroughly. The solution is now ready for testing.

· For Shrimp Samples:Homogenization: Take a shrimp tissue sample, grind or homogenize it fully. Weigh exactly 1 g of the sample into a 15 mL centrifuge tube.

· Phase Separation: Add 0.5 mL of Heavy Metal Cd Reagent A and 3 mL of Heavy Metal Cd Reagent B. Cap tightly, fully stir and mix for 3 minutes, then centrifuge at 4000 rpm for 2 minutes.

· Reaction Mix (Key Step): Extract exactly 100 µL of the clear supernatant into a clean 1.5 mL centrifuge tube. Add 10 µL of Heavy Metal Cd Chelating Agent and 1 mL of purified water, then stir and mix well.

· Final Activation: Add 10 µL of Heavy Metal Cd Reagent C, stir and mix completely. The solution is now ready for testing.

2. Running the Assay

· Open the strip package tube, take out the required test strips and microwells, and apply necessary markings. (Note: Re-cap the strip container immediately to protect remaining strips from ambient moisture).

· Pipette 120 µL of the prepared fish or shrimp sample solution directly into a microwell (which contains lyophilized reagent). Mix slowly but thoroughly using the pipette tip, then incubate at room temperature for 3 minutes.

· Insert the test strip into the microwell and start your timer.

· Interpret visual results between 10 to 13 minutes. Do not read after 13 minutes, as late chemical shifts are strictly invalid.

Results Determination & Action Guide

· Negative (-): Both the Control (C) line and Test (T) line develop a strong, visible color band. This confirms that cadmium levels in the seafood tissue are safely below the regulatory threshold.

· Positive (+): The Test (T) line is visibly lighter than the Control (C) line or fails to appear completely. This indicates a contamination event where the heavy metal cadmium concentration meets or exceeds the target cutoff limit (0.1 mg/kg for fish / 0.5 mg/kg for shrimp).

· Invalid: The Control (C) line fails to show any visible color, regardless of the appearance of the T line. The sample must be re-tested using a brand new microwell and strip.

Crucial Safety & Handling Precautions

· This kit provides qualitative detection ONLY and serves as a rapid screening tool. It is not suitable for determining exact quantitative concentrations. Confirmatory analytical instrumentation methods should be used to verify positive findings.

· Never touch the exposed white reaction area in the middle of the test strip. Always handle the strip by the top end labeled 'FSTest Cd'.

· Check the integrity of the packaging tube before opening. If the container is broken or cracked, the strips may have absorbed moisture from the air, which can cause inaccurate readings.

· All strips and microwells are strictly single-use items. Ensure assays are completed within the valid expiration window stamped on the package.