In the field of environmental monitoring, the accuracy and reliability of data are crucial. Quartz tube, as a high-performance glass material, has become an indispensable core component in many key environmental analysis instruments due to its unique optical, thermal, and chemical properties.

Material characteristics of quartz tube: the foundation of excellent performance

The performance advantage of quartz tubes (mainly composed of high-purity silicon dioxide) is a prerequisite for their stable operation in harsh environmental monitoring environments. Its core features include:

1. High transmittance: It has extremely high transmittance for ultraviolet, visible, and near-infrared light (up to 93% or more), especially in analysis that requires high ultraviolet sensitivity, which is irreplaceable.

2. High temperature resistance: The softening point is as high as about 1730 ℃, and it can work stably for a long time in high temperature environments above 1000 ℃ without deformation or crystallization.

3. Thermal stability: The coefficient of thermal expansion is extremely low (about 5.5 × 10 ⁻⁷/℃), and it can withstand drastic temperature changes without cracking.

4. Chemical inertness: Except for hydrofluoric acid and hot phosphoric acid, it hardly reacts with other acidic substances, has strong resistance to acid and alkali corrosion, and is not easily contaminated by sample gases or liquids.

These characteristics make quartz tubes an ideal "window" and "reaction chamber" for connecting harsh sampling environments with precision optical/electrical detection systems.

Core application areas and specific product manifestations

The application of quartz tubes in environmental instruments is mainly reflected in the following aspects:

Application 1: Continuous Emission Monitoring System (CEMS) for flue gas emissions

Product application: Quartz tubes are used as sample cells/gas flow cells in non dispersive infrared (NDIR) gas analyzers and ultraviolet differential absorption spectroscopy (DOAS) systems.

The core problem to be solved is that industrial flue gas usually has the characteristics of high temperature, high humidity, and strong corrosiveness (containing SO ₂, NOx, HCl, etc.). Ordinary glass or metal tanks may experience a decrease in measurement accuracy or even damage due to corrosion, adsorption, or high-temperature deformation.

The role and advantages of quartz tubes:

Corrosion resistant window: As the entrance and exit window for analyzing the optical path, quartz tubes can be exposed to corrosive smoke for a long time, keeping the optical surface clean and ensuring stable transmission of optical signals.

High temperature sample pool: High temperature flue gas can be directly introduced into the quartz sample pool for analysis, without the need for complex and potentially component loss cooling pretreatment, achieving in-situ and real-time monitoring.

Verifiable case: For example, in Siemens ULTRAMAT 23 or ABB AO2000 series CEMS analyzers, the sample cells of their core measurement units are made of high-purity quartz glass to ensure accurate measurement of gases such as SO ₂ and NO.

Application 2: Water Quality Analysis - Total Phosphorus/Total Nitrogen Online Analyzer

Product application: Quartz tubes are used as digestion tubes in online total phosphorus/total nitrogen analyzers based on high-temperature and high-pressure digestion principles.

The core problem to be solved is that phosphorus and nitrogen compounds in water samples need to be completely dissolved and converted into measurable orthophosphate or nitrate under high temperature (usually 120-150 ℃), high pressure, and the presence of strong oxidants (potassium persulfate).

The role and advantages of quartz tubes:

Resistant to extreme dissolution environments: Quartz tubes can withstand high temperature, high pressure, and strong oxidant corrosion simultaneously, making them one of the few materials that can work stably for a long time under such comprehensive and harsh conditions.

Optical transparency: After digestion is completed, some instrument designs allow the optical path to directly pass through the quartz tube wall for colorimetric analysis of the digestion solution, simplifying the flow path design and reducing cross contamination.

Verified cases: The NPW-160 series total nitrogen/total phosphorus online analyzer from Hach company and the QuickTON series analyzer from LAR company in Germany both explicitly use quartz glass digestion tubes as their core high-temperature reaction components.

Application 3: Online monitoring of volatile organic compounds (VOCs)

Product application: In the online VOCs monitoring system based on gas chromatography (GC) technology, quartz tubes are used as liners and installed inside the chromatographic injection port.

The core problem to be solved is that VOCs samples in the ambient air need to vaporize instantly at the injection port before entering the chromatographic column. This process may result in inaccurate quantification, tailing of peak shapes, and system contamination due to incomplete vaporization or thermal decomposition of certain high boiling point components.

The role and advantages of quartz tubes:

Inert surface: The chemical inertness of quartz ensures that its surface will not adsorb or catalyze reactions with sensitive VOCs molecules, ensuring the integrity of the sample.

Fast and uniform heat conduction: Quartz tubes can quickly reach the set temperature, enabling the sample to achieve "flash evaporation" instant vaporization, reducing thermal decomposition, obtaining sharp and symmetrical chromatographic peaks, and improving quantitative accuracy.

Verifiable case: Almost all mainstream online GC-MS or GC-FID monitoring systems, such as Thermo Fisher's Trace 1300 series online GC, come standard with or recommend the use of deactivated quartz liners for their injection ports.

The application of quartz tubes in environmental instruments is not accidental, but an inevitable result of their material properties highly matching the stringent monitoring requirements. It effectively solves a series of technical bottlenecks such as high temperature, corrosion, adsorption, and thermal instability in core areas such as CEMS, online water quality analysis, and VOCs monitoring by playing key roles such as sample tanks, digestion tubes, and chromatographic liners, thereby ensuring the accuracy, real-time performance, and reliability of environmental monitoring data.

With the increasingly strict environmental standards and the continuous development of monitoring technology, higher requirements have been put forward for the purity, geometric structure design, and surface treatment technology of quartz tubes. In the future, customized and functional quartz components will continue to play an irreplaceable role in improving the detection limit, stability, and automation level of environmental instruments.

Luverre Quartz can manufacture customized quartz tubes in various shapes, such as spiral, square, round, with processing including cutting, bending, welding, etc., and available in different colors, such as transparent quartz tubes, opaque quartz tubes, milky white quartz tubes, red quartz tubes, and so on.