MUHWA 2mL HPLC Vials — Amber, 9-425 Thread, Writing Area, 100/Pack
Light-sensitive analytes have no patience for clear glass. If you're running retinoids, riboflavin, certain antibiotics, or any compound with a conjugated double-bond system, a few minutes of exposure to lab fluorescent lighting can degrade your sample enough to show up as an extra peak — or worse, as a missing peak that you can't explain in your audit trail.
These amber vials block UV and short-wavelength visible light. The glass itself is Type I borosilicate — the same chemically inert glass you expect from an HPLC vial, just with an amber additive that doesn't leach into your mobile phase. The 9-425 thread is the industry-standard short thread for 2mL autosampler vials — it's compatible with 9mm screw caps and septa across all major autosampler brands: Agilent, Waters, Shimadzu, Thermo.
The writing area
Each vial has a small frosted patch on the side — about 6mm by 12mm — where you can write with a pencil or fine-tip permanent marker. Pencil marks survive solvent exposure and won't dissolve into your sample the way some ink formulations can. The frosted surface gives enough tooth for graphite to adhere. If you're running a sequence of 50 vials, write the vial number on the patch — it's faster than relying on tray position when you're troubleshooting an unexpected result.
Glass quality and the baseline
Type I borosilicate has low extractable metal content — the sodium, calcium, and magnesium that can leach out of soda-lime glass and create ghost peaks in your chromatogram aren't present at detectable levels here. If you're running a gradient to 100% organic and your baseline is clean, the vial isn't contributing to the noise. The glass surface is untreated — no silanization, no coatings — which means it's compatible with aqueous and organic mobile phases alike without introducing surface-active artifacts.
Specifications
| Volume |
2mL (nominal), ~1.5mL fill volume |
| Glass type |
Type I borosilicate, amber |
| Thread |
9-425 (standard short thread) |
| Dimensions |
12mm OD x 32mm height |
| Writing area |
Frosted patch, pencil-compatible |
| Pack size |
100 vials |
| Compatibility |
Agilent, Waters, Shimadzu, Thermo, CTC autosamplers |
When to use inserts
If your sample volume is under 200µL, use a 200µL glass or plastic insert inside the vial. The 9-425 vial accepts standard 5.7mm or 6mm OD conical inserts with a polyspring. Without an insert, 200µL of liquid in a 2mL vial will have a very low fill height — the autosampler needle may not reach it, or you'll get inconsistent injection volumes due to needle depth variation. The rule of thumb: if your total sample is less than 500µL, use an insert.
