ROX Reference Dye for real-time PCR instruments that require passive reference normalization (e.g. ABI, Stratagene). Supplied at 50 µmol (100×) stock; final reaction concentration typically 500 nmol (1×) per instrument protocol.
What is ROX passive reference dye?
ROX (carboxy-X-rhodamine) is a passive reference dye for real-time PCR. Its fluorescence does not change during amplification and it does not take part in the reaction, so instruments that use it divide the reporter signal (SYBR Green, FAM and others) by the ROX signal. This corrects well-to-well differences from pipetting, uneven illumination, optics and condensation. ROX absorbs in the orange-red region, with published excitation maxima of about 575–580 nm and emission maxima of about 600–620 nm depending on the source; use your instrument’s ROX filter set. A flat ROX trace in the multicomponent plot also helps you spot bubbles or evaporation in a single well.
High ROX or low ROX? Older ABI instruments (7000/7300/7700/7900HT, StepOne/StepOnePlus) use high ROX (1×, ~500 nM). ABI 7500/7500 Fast and several Stratagene, MJ Research and Corbett models use low ROX (0.1×, ~50 nM). Roche, Bio-Rad and Eppendorf cyclers do not need ROX. The volumes for each are in the table below.
Key Features
- Normalizes well-to-well signal differences from pipetting error
- Compatible with ABI and Stratagene real-time instruments
- Simple 100× stock — dilute per your instrument’s protocol
- Small pack sizes ideal for evaluation (25 µl / 100 µl)
Specifications
| Pack sizes | 25 µl (CYPC3801) / 100 µl (CYPC3802) |
| Concentration | 50 µmol (100×) stock; working concentration ~500 nmol (1×) |
| Storage | -20°C; stable for at least 12 months |
| Shipping | Ice packs; store at the listed temperature on arrival |
Typical Applications
- Well-to-well fluorescence normalization on ABI- or Stratagene-type real-time instruments.
- High-ROX instruments (1×) vs low-ROX (0.1×) — volumes are in the product table.
- Do not add ROX on Roche, Bio-Rad, or Eppendorf cyclers (manual: not needed).
Performance at a glance
| Stock | 50 µmol (100×) |
| Final concentration | 500 nmol (1×, high) or 50 nmol (0.1×, low) depending on instrument (manual) |
| Instruments — 1× (0.5 µl per 50-µl reaction) | ABI PRISM 7000/7300/7700/7900HT, ABI StepOne / StepOne Plus |
| Instruments — 0.1× (0.05 µl per 50-µl reaction) | ABI 7500/7500 Fast, Stratagene Mx3000P/Mx3005P/Mx4000, MJ Research Chromo4/Opticon, Corbett Rotor-Gene 3000 |
| No ROX needed | Roche, Bio-Rad, Eppendorf cyclers (manual) |
| Quick use | High-ROX: 25 µl per 1.25 ml 2× SYBR qPCR Mix; low-ROX: 2.5 µl per 1.25 ml; subtract ROX volume from ddH₂O |
| Small additions | Dilute the dye 10–20× in water before adding 0.05 µl so the volume is pipettable |
| Storage / pack sizes | −20°C, at least 12 months; CYPC3801 (25 µl) · CYPC3802 (100 µl) |
Limits and handling
- For laboratory research use only. Not for diagnostic or therapeutic use.
- Shipped with ice packs. Store at the temperature in the specifications table on arrival.
- Store at −20°C (manual: at least 12 months).
- Roche, Bio-Rad, and Eppendorf cyclers typically do not need ROX. ABI 7000/7300/7700/7900/StepOne use 1×; ABI 7500 and several Stratagene/MJ/Corbett models use 0.1×.
- For 0.05 µl additions, dilute the dye 10–20× in water first so the volume is pipettable.
Who sets these specifications
Changyu Bio supplies Cat# CYPC38 and is responsible for the specifications on this page. Confirm pack sizes, storage, and protocol against the PDF manual before use. Quotes: market@changyubio.com or WhatsApp +86 18665577773.
ROX Reference Dye FAQ
Which instruments need ROX?
ABI and Stratagene-type instruments that use passive reference normalization — see the instrument table above for exact 1× vs 0.1× requirements. Roche, Bio-Rad and Eppendorf cyclers typically do not need ROX (manual).
How do I add ROX to my qPCR mix?
For high-ROX instruments (1×), add 25 µl ROX per 1.25 ml of 2× SYBR qPCR Mix (CYPC33); for low-ROX (0.1×), add 2.5 µl. Mix well and use directly. Subtract the ROX volume from the ddH₂O in the reaction.
What if my reaction needs only 0.05 µl of ROX?
Dilute the ROX Reference Dye 10–20× in water first, so the volume you pipette is accurate and reproducible (manual).
Cat# CYPC38 — For research use only (RUO). Not for diagnostic or clinical use. Contact market@changyubio.com or WhatsApp +86 18665577773 for pricing and export delivery to Africa, Southeast Asia and worldwide.