Principle and Composition

Virus Preservation Solution (10×, Inactivated, Extraction‑Free, Guanidine, Pink) leverages the chaotropic properties of guanidine salts to rapidly disrupt viral envelopes and capsids upon sample contact, effectively inactivating infectious particles and rendering specimens safe for downstream handling outside high-containment environments.

The pink indicator dye provides a convenient visual cue confirming the presence of active solution in collection tubes or reaction wells. Because the guanidine-based lysis chemistry simultaneously releases viral nucleic acids into solution, collected samples can be added directly to reverse-transcription PCR (RT-PCR) or quantitative PCR (qPCR) master mixes, bypassing conventional spin-column or magnetic-bead extraction workflows and reducing both hands-on time and the risk of nucleic acid loss during purification.

Materials and Equipment

Before beginning, ensure the following materials are available:

• Virus Preservation Solution 10× stock (SKU E1529465)
• Nuclease-free water or appropriate diluent for preparing 1× working solution
• Sterile collection swabs (nasopharyngeal, oropharyngeal, or other specimen type as required)
• Sterile screw-cap collection tubes
• Calibrated pipettes and nuclease-free tips
• RT-PCR or qPCR instrument with validated primers and probes for target virus
• Personal protective equipment (PPE): gloves, lab coat, eye protection
• Biohazard waste containers for specimen disposal

Confirm that all reagents are within their stated expiry dates and that the 10× solution displays the characteristic pink color prior to use. Discard any solution that appears colorless or turbid.

Step-by-Step Protocol

Step 1 — Prepare 1× Working Solution
Dilute the 10× Virus Preservation Solution stock 1:9 with nuclease-free water (e.g., 1 mL stock + 9 mL water) to obtain a 1× working solution. Mix gently by inversion. The resulting solution should retain a visible pink hue.

Step 2 — Sample Collection
Dispense an appropriate volume of 1× working solution into sterile collection tubes (volume per tube should be determined according to your specific assay requirements and swab type). Collect the biological specimen (e.g., nasopharyngeal swab) and immediately immerse the swab in the tube containing the 1× working solution. Snap off or cut the swab handle and cap the tube securely.

Step 3 — Inactivation
Vortex the capped tube briefly (5–10 seconds) to ensure thorough mixing of specimen with the preservation solution. The guanidine components inactivate viral pathogens rapidly upon contact. For biosafety compliance, confirm inactivation time with your institutional biosafety officer before removing samples from containment.

Step 4 — Direct Addition to PCR
Add the recommended volume of inactivated sample lysate directly to your RT-PCR or qPCR reaction mix according to the validated assay protocol. Because no extraction step is required, minimize freeze-thaw cycles to preserve nucleic acid integrity. Typical addition volumes range from 1–5 µL per 20–25 µL reaction, but must be optimized for each assay system.

Step 5 — PCR Amplification and Detection
Run the RT-PCR or qPCR program per the validated cycling conditions for your target pathogen. Interpret results using established positive and negative controls included in each run.

Troubleshooting

No amplification detected: Verify that the 10× stock was correctly diluted and that the pink color is present in the working solution. Check that the sample addition volume does not exceed the inhibitory threshold for your PCR system, as guanidine salts can inhibit polymerase activity at high concentrations. Optimize the sample-to-reaction ratio.

High background or non-specific amplification: Ensure that positive and negative controls are included in every run. Review primer and probe specificity. Consider reducing the volume of lysate added per reaction.

Loss of pink color: Discard the solution and prepare a fresh 1× working solution from the 10× stock. Loss of color may indicate degradation or contamination of the indicator dye.

Inconsistent Ct values between replicates: Ensure thorough vortexing after specimen collection and prior to PCR setup. Use calibrated pipettes and maintain cold-chain conditions if samples are not processed immediately.