石英キュベットの選び方

1. 石英 vs. Glass: Why 材質 Matters First

Every キュベット purchase starts with one question: what 波長 do you measure? Fused 石英 (溶融シリカ) transmits light from ~190 nm in the far UV through the visible range to ~2500 nm in the near 赤外線, while borosilicate glass cuts off below ~320 nm. If your work involves DNA/RNA quantification (260 nm), protein assays (280 nm), most pharmaceutical methods or any measurement below 320 nm, you need 石英 — glass セルs simply block the light your detector depends on.

Property	Fused 石英 (JGS1)	Borosilicate glass
Transmission range	190 – 2500 nm	320 – 2500 nm
UV cut-off	~170 nm	~320 nm
Typical applications	DNA/RNA, protein, kinetics, UV-Vis	Visible-range colorimetry only
Cost	Higher	Low

Browse our full range of 石英キュベット for UV分光光度法, or the budget-friendly glass キュベット if you only work in the visible range.

2. 石英 グレードs: JGS1, JGS2 and JGS3

In China and much of Asia, 溶融石英 is グレードd JGS1 / JGS2 / JGS3 (equivalent to the German Heraeus グレードs and US 標準 グレードs). The グレード defines purity and UV transmission:

グレード	UV cut-off	Best for
JGS1 (far-UV グレード)	~170 nm	DNA/protein at 260/280 nm, kinetics, anything below 220 nm
JGS2 (UV グレード)	~200 nm	Routine UV-Vis above 200 nm
JGS3 (IR グレード)	Visible / NIR	Near-IR work, high-temperature applications

Rule of thumb: for any bio-chemistry or pharmaceutical application, choose JGS1 far-UV グレード. The price difference vs. JGS2 is small relative to the cost of re-running a failed assay. All Scuvette 10 mm 石英キュベット are manufactured from JGS1 溶融シリカ as 標準.

3. 光路長: Match It to Your Sample Concentration

光路 length is the distance the light beam travels through the sample — the single most important dimension of a キュベット. Per the Beer–Lambert law, absorbance scales linearly with 光路長: the same solution gives a 10× stronger signal in a 10 mm セル than in a 1 mm セル.

• 10 mm (標準) — the universal セル for most UV-Vis spectrophotometers. Use it for typical dilute samples. Browse 10 mm 石英キュベット →
• 1–5 mm (短光路) — for concentrated or highly absorbing samples. A 短光路 keeps absorbance on-scale without dilution, saving time and avoiding dilution errors. Short 光路-length セルs →
• 0.1–0.5 mm (ultra-short) — for neat liquids, concentrated protein solutions or IR work. 0.1 mm セル / 0.5 mm セル
• 20–100 mm (長光路) — for 微量分析, turbid samples and low-concentration measurements where you need maximum sensitivity. Long 光路-length キュベット →

4. 窓構成: 2, 4 or 5 窓s

The number of polished optical 窓s determines what the セル can do:

• 2-窓 — two opposing polished 窓s for 標準 吸光度測定. The most common and most economical 構成.
• 4-窓 — four polished 窓s, allowing fluorescence measurements at right angles (excitation perpendicular to emission) or absorbance along two axes. Choose this if the same セル will be used for both absorbance and fluorescence. 蛍光キュベット →
• 5-窓 — four side 窓s plus a polished bottom, used in special geometries such as bottom-reading or multi-angle applications.

Example: the screw-cap 10 mm 4-窓 セル is a popular choice for fluorescence work with volatile samples.

5. Sample 容積: Macro, Semi-Micro, Sub-Micro

Your precious sample 容積 often dictates the セル format. 標準 10 mm セルs hold roughly 3.5 mL; if you only have 50–100 µL, that's the difference between using a micro セル or diluting (and compromising) your sample.

• Macro (標準 容積) — ~3.5 mL fill; for routine measurements with ample sample. 標準 容積 セルs →
• Semi-micro — ~1.5 mL; a middle ground that fits most 標準 holders.
• Sub-micro — down to ~50–350 µL; 最適 proteins, nucleic acids and other precious samples. 石英 微量キュベットs →
• Black-wall micro — masked side 窓s that block stray light for low-容積 fluorescence; reduces background and improves detection limits. Black-wall 10 mm セル →

Note: 容積 capacity is not the same as beam 光路. A sub-micro セル still has a 10 mm 光路 — it just narrows the internal width so the beam passes through a smaller liquid 容積. Verify both dimensions on the spec sheet before ordering.

6. Sealing: 標準 Caps vs. スクリューキャップ

If your samples are volatile, oxygen-sensitive, radioactive, or need to be stored inside the セル, a 標準 snap cap may not provide an adequate seal.

• 標準 (flip-top / snap cap) — easy to open and fill; fine for routine aqueous samples.
• Screw cap — an M12 ねじ山ed PTFE cap that seals the セル tightly. Prevents evaporation during long kinetic runs, protects oxygen-sensitive samples, allows inert-gas blanketing, and is essential for radioactive or biohazardous samples. PTFE is chemically inert, so the cap is compatible with nearly every solvent. スクリューキャップキュベット →
• Interchangeable caps — solid PTFE, silicone or injectable (septum) caps let you add reagents through a syringe without opening the セル. See available caps →

Popular sealed-セル options include the 10 mm screw-cap 2-窓 セル and the 10 mm 5-窓 screw-cap セル for bottom-reading instruments.

7. How to Read a キュベット Spec Sheet

A good 石英キュベット spec sheet tells you exactly what you're 購入. Look for these numbers:

Spec	Why it matters	Typical good value
External dimensions	Must fit your instrument's sample holder	12.5 × 12.5 × 45 mm (10 mm 光路)
光路 length tolerance	Tight tolerance = reproducible readings	±0.01 mm (precision グレード)
Transmission / 透過率	Confirms optical グレード of the 石英	≥ 85% @ 190 nm; ≥ 93% @ 220 nm (JGS1, 10 mm)
Parallelism / flatness	Affects beam alignment and accuracy	≤ 2′ parallelism (arc-minutes)
窓s	Polished faces vs. frosted (non-optical) faces	2 / 4 / 5 polished 窓s

Also confirm working temperature and chemical compatibility — 石英 tolerates most acids and organics but is attacked by hydrofluoric acid and strong alkalis. See our キュベットケアガイド for cleaning and handling details.

8. Instrument Compatibility & Matched Pairs

Most modern UV-Vis instruments (Agilent, Shimadzu, Thermo, PerkinElmer, Hach, etc.) accept 標準 10 mm 光路 セルs with 12.5 mm external width. Before ordering:

• Check the holder geometry — external width (12.5 mm is 標準), セル 高さ and whether the beam sits at the 標準 8.5–15 mm 高さ. Unusual geometries (e.g. bottom-reading or flow セルs) need dedicated 製品.
• Ask for a drawing — when in doubt, request a dimensional drawing; our engineers can confirm fit against your instrument model.
• Consider matched pairs — for quantitative assays and baseline-critical kinetics, order two セルs matched to ≤ 0.1% 光路-length tolerance and identical transmission. Reference and sample セルs should always be from the same manufacturing batch.
• Custom セルs — need a non-標準 光路, 窓, port or 材質? As a factory, we make custom optical セルs to your drawing with short lead times. Tell us your requirement →

9. Your Quick Decision Checklist

1. Working 波長 below 320 nm? → 石英 (JGS1 for < 220 nm).
2. Sample absorbance high? → shorten the 光路長 (1–5 mm).
3. Sample 容積 under ~1 mL? → semi-micro or sub-micro セル.
4. Fluorescence measurement? → 4-窓 セル.
5. Volatile or oxygen-sensitive sample? → screw cap with PTFE or septum cap.
6. Trace analysis? → 20–100 mm long-光路 セル.
7. Quantitative precision critical? → matched pair, ±0.01 mm tolerance.
8. Non-標準 size or port? → custom セル to your drawing.