Why Should A Dedicated Moisture-Proof Box Be Chosen for FTIR

FTIR is an instrument that analyzes molecular structure and chemical composition by detecting the absorption/transmission characteristics of substances to infrared light.

Core purpose:

1. Qualitative analysis: Identify the functional groups and chemical bonds of the substance (such as C-H, O-H), and determine the type of the substance (such as organic, inorganic, polymer).

2. Quantitative analysis: Measure the content of each component in the mixture (such as impurity content, component proportion).

3. Application scenarios: Cover fields such as chemistry, materials, medicine, and environmental protection, for example, detecting plastic components, drug purity, food additives, or analyzing pollutant types.

Simple analogy: It’s like conducting an “infrared fingerprint” test on molecules. Each substance has a unique infrared absorption spectrum, which can quickly “match” and identify the components.

I. Specific Application Cases in Different Fields (Practical Scenarios + Detection Objectives)

1. In the field of chemistry/chemical engineering: Identify the functional groups of organic synthesis products (such as confirming the C=O bond in esters), determine if the reaction is complete; Analyze the purity of solvents (such as the moisture content in ethanol).

2. In the materials field: Identify the types of plastics/rubber (such as differentiating PE and PVC), detect the fiber composition (cotton, proportion of synthetic fibers blend); Analyze the resin type of coatings/adhesives.

3. In the pharmaceutical field: Verify the active ingredients of drugs (such as the characteristic spectrum of aspirin), detect drug impurities (for purity control); Identify the authenticity of medicinal herbs (such as the infrared fingerprint of licorice).

4. In the food field: Detect food additives (such as preservatives, pigments), analyze the degree of oil rancidity; Identify the authenticity of products like honey and milk powder (to avoid adulteration).

5. In the environmental protection field: Qualitative analysis of pollutants in wastewater/gas (such as volatile organic compounds VOCs), detection of heavy metal complexes in soil.

6. In the electronic/semiconductor field: Analyze the composition of chip packaging materials, detect residual pollutants on circuit boards (such as soldering flux).

II. Key Technical Parameters (Core Indicators + Popular Interpretation)

1. Wavenumber range: Commonly 4000 – 400 cm⁻¹ (mid-infrared region), covering the characteristic absorption peaks of the vast majority of organic/inorganic substances. The wider the range, the more types of substances can be detected.

2. Resolution: Usually 0.5 – 4 cm⁻¹. The higher the resolution, the clearer the peak shape, and it can distinguish substances with similar structures (such as isomers).

3. Signal-to-Noise Ratio (S/N): The higher the value, the cleaner the spectrum (less noise), and it is suitable for detecting low-content impurities (such as trace pollutants).

4. Scanning speed: The number of scans per unit time. The faster the speed, the higher the detection efficiency (such as rapid screening of batch samples).

5. Sample cell/attachment: Transmission cell (liquid/gas), attenuated total reflection (ATR, no pre-treatment required for solid/viscous samples), diffuse reflection (powder samples). The more attachments, the wider the applicable scenarios.

Why choose a dedicated moisture-proof box?

Due to the fact that the beam splitter, detector and sample chamber window in the core components of the Fourier infrared spectrometer are all made of potassium bromide material, as is well known, potassium bromide is the material with the best transmittance in the infrared band. However, it has a fatal drawback, which is that it is extremely prone to absorbing moisture. After absorbing moisture, the surface of the components will fog up and deliquesce. The infrared spectrometer manufacturer will set up double seals inside during the design process. However, as time goes by and with the changes in temperature and humidity throughout the seasons, the sealing strips will age and cracks that are invisible to the naked eye will appear. This leads to the components absorbing moisture and getting damaged, causing the spectrometer to be unable to function properly. See Figure 1 (Interferometer, detector, beam splitter. Once the components get wet, the surface of the components will deliquesce. This part cannot be repaired due to special processing and can only be replaced with new components, with a cost of up to 4,000 – 12,000  US dollars).

Everyone realized that it was necessary to control the environmental humidity to protect the infrared spectrometers. The first thing that came to mind was to install a dehumidifier. The dehumidifier worked immediately, and within one hour of starting up in an environment with 90% humidity, the water collection box could be filled up. Different power dehumidifier models were configured based on the size of different laboratories. Over a period of time, the dehumidifier became a standard accessory product for each infrared spectrometer manufacturer. However, as time went on, some fatal problems emerged with the dehumidifiers during use.

Firstly, most laboratories turned on the dehumidifiers during working hours in humid seasons and would pour out the water from the dehumidifier’s water collection box and continue to start up after work. But the dehumidifier would stop running when the water level was full, and it basically stopped running around 10 p.m. This was the reason why even with a dehumidifier, infrared spectrometers could still be damaged. 99% of the infrared spectrometers that got damp and damaged occurred during nights when there was no one on duty and the dehumidification equipment was not working. During university holidays and during the COVID-19 pandemic, due to no one being on duty, a large number of infrared spectrometers required warranty repairs. Some customers, in order to continuously reduce the humidity, connected the drainage pipe of the dehumidifier to the window (to avoid the dehumidifier stopping due to full water level). However, the principle of the dehumidifier is that the compressor starts, and this long-term operation not only consumes a lot of electricity but also may cause fire hazards due to aging wiring.

In response to this predicament, our company has developed an infrared spectrometer electronic moisture-proof cabinet. This product features a dedicated dehumidification device, which can effectively protect the interferometer and detector from damage caused by moisture absorption. The moisture-proof box complies with the PC/JEDECJ-STD-033B operation standard (i.e., humidity does not exceed 50RH%). The product can monitor humidity in real time and automatically activate the dehumidification function when the humidity exceeds the set value. It does not require consumables, has low energy consumption, and is currently sold throughout the country and exported to overseas countries and regions, providing protection for all global Fourier infrared spectrometer users.

Product Principle:

The moisture-proof module inside the moisture-proof box adopts the solid-state electrolytic technology of molecular layer film. It adsorbs water molecules within the space range into the module. The internal chemical molecular layer film removes the water vapor in the box through electrolytic micro-heating, without generating wave-like water, and does not require regular drainage or cleaning. The module is equipped with an intelligent sensing device. When the set humidity is exceeded, the moisture-proof box will automatically start dehumidification. This product only has dehumidification function and no humidification function. The molecular layer film is a special material composed of a combination of molecular sieves and silica gel components. This electronic moisture-proof box has extremely low power consumption. During daily use, there is no need to replace consumables. The dehumidification module has a validity period of 5-8 years (calculated based on the customer’s experimental environment).

Product features:

1. Humidity control range: 25RH% – 50RH%, front LCD screen with dual display of temperature and humidity

2. Opening/closing method: The upper cover is designed with damping hinge for opening and closing, effectively utilizing the upper space to avoid space waste and operational inconvenience caused by the double-door design

3. Wiring design: Hidden protection for the wiring and power supply lines, and an added protection board for the PCB circuit board

4. Dehumidification system: Intelligent humidity sensing module, using a microcomputer program system with a recyclable and circulating moisture-absorbing film to control humidity. When the humidity inside the chamber exceeds the set humidity level, the system will intelligently start dehumidification, without consumables

5. Operation: Even when powered off, it has a moisture absorption protection function. It can still use the chemical moisture absorption backup function to continue dehumidification. The humidity increase within 24 hours will not exceed 10%

Customer Case:

Applicable to all brands of Fourier Transform Infrared Spectrometers

Customized moisture-proof cabinets can be provided according to customer requirements:

The moisture-proof cabinet is suitable for analytical instruments; for example, it can be used in conjunction with thermogravimetry, infrared microscopes, optical fiber probes, etc.