Material Guide

Quartz Cuvette UV Cut-Off: 190 nm vs 200 nm vs 220 nm

What the UV cut-off of a quartz cuvette means, how JGS1 / JGS2 / JGS3 differ, and why 190 nm transmission matters for your measurements.

1. What "UV Cut-Off" Means

The UV cut-off is the wavelength below which a material stops transmitting. Below the cut-off, absorbance rises steeply and measurements become unreliable. Quartz cut-offs are quoted at the point where transmittance drops sharply (often ~10% or the conventional 1 mm path reference).

2. Cut-Offs by Grade

Grade	Origin	Typical UV cut-off	Safe measurement range
JGS1 (synthetic)	Synthetic fused silica	~190 nm	190 – 2500 nm
JGS2 (flame-fused)	Natural quartz	~200 – 220 nm	220 – 2500 nm (careful below 220)
JGS3 (IR-grade)	Natural quartz, vacuum-fused	~220 nm (UV)	220 nm – 3500 nm
Optical glass	Borosilicate	~320 nm	Visible only

3. Why 190 nm Matters

Measurements at 200–220 nm (peptide bonds ~210 nm, some pharmaceutical methods) need a cell that transmits below the measurement wavelength — JGS1 only.
Measurements below 200 nm (e.g. 190 nm gas-phase or special methods) require synthetic fused silica.
DNA/protein at 260/280 nm — every quartz grade works; JGS1 is future-proof for all UV work.

4. How to Verify Your Cell’s Cut-Off

Scan an empty cell against air from 190 nm up. A JGS1 cell should stay flat and transmissive down to ~190 nm; a JGS2 cell begins to absorb around 200–220 nm. scuvette includes transmission data on request, and every standard cell is JGS1.

A practical tip: if your routine methods never go below 240 nm, JGS2-class cells are acceptable — but JGS1 costs little more and removes the risk entirely. We stock JGS1 as standard.

Need cells for deep-UV work? Our JGS1 standard line covers 190 nm.
Send us your instrument model and sample type — our engineers will reply within 1 business day with the right specification and a firm price. Contact Scuvette →

Need a hand? Our engineers can help you select the right cuvette for your instrument and application — or supply custom optical cells to your drawing. Contact Scuvette →

Frequently Asked Questions

What does UV cutoff mean for a cuvette?

The UV cutoff is the shortest wavelength at which the cell material still transmits useful light, usually taken where transmission falls to about 50 percent or 10 percent of its peak. Below this point the material absorbs or scatters the light.

What is the cutoff of quartz versus glass cuvettes?

Glass and most plastic cells cut off around 340 to 350 nm, so they cannot be used in the deep UV. Fused quartz transmits much further: high-purity grades reach about 185 nm, while standard UV-Vis quartz is specified for roughly 200 to 250 nm and above.

Which quartz grade should I choose for low-wavelength UV?

For work below about 300 nm use high-purity deep-UV quartz. Our UV-Vis grade covers about 360 to 1100 nm and our IR grade covers about 260 to 3500 nm, so pick the grade whose rated range sits below your measurement wavelength.

How does cutoff affect my measurement?

If your analyte absorbs near or below the cell's cutoff, you will see a rising baseline and loss of signal. Choose a cell whose cutoff is comfortably below the wavelength you measure.

Do I always need the deepest-UV quartz?

No. For visible and near-UV work above about 360 nm, standard UV-Vis quartz is sufficient and more economical. Reserve deep-UV quartz for far-UV protein, nucleic-acid or vacuum-UV applications.