1. Clarify the analysis needs
The first step in selecting a spectrophotometer is to define the core analytical tasks of the laboratory. There are different requirements for instrument performance for different types of DUT: if it involves nucleic acid or protein quantification, it is necessary to cover the ultraviolet-visible light band (200-850nm), and pay attention to the automatic calculation function of purity ratios such as A260/A280; For cellular solutions or microarray samples, models with fluorescence detection modules or multi-well plate adaptation capabilities are more suitable. For high-concentration samples, consider whether the instrument supports automatic light path adjustment to avoid tedious dilution steps. In addition, it is crucial to distinguish between ultraviolet-visible (UV-Vis), infrared (IR) and fluorophotometers, with UV-Vis for regular quantification, IR for functional group identification, and fluorescence for trace detection.
2. Evaluate the optical system and performance indicators
The optical design of the instrument directly determines the accuracy and stability of the data, mainly including the following key technical parameters:
| Performance dimensions | Key considerations and selection points |
|---|---|
| Wavelength range and accuracy | Conventional UV-Vis covers 190-1100nm; Wavelength accuracy should be at least ±0.3nm, and resolution should be better than 1.5nm to ensure spectral detail. |
| Beam type | The dual-beam design can compensate for light source fluctuations in real time, suitable for long-term dynamics and high-precision scanning; The single-beam structure is simple and low-cost, making it suitable for regular quantitative analysis. |
| Detector efficiency | The CCD array detector has low noise and high quantum efficiency, which is suitable for rapid spectral acquisition. The photomultiplier tube has outstanding sensitivity in low-light detection. |
| Stray light level | Low stray light is a prerequisite for accurate measurement of high-concentration samples, such as NaI stray light <0.05%T or <0.00005%T at 220nm. |
| Spectral bandwidth | Adjustable bandwidths (e.g., 0.1-5nm) enhance method adaptability; 2nm bandwidth is sufficient for routine analysis, and 1nm or narrower for high-precision operation. |
3. Consider the operating experience and environmental adaptation
The ease of use of the equipment is equally well matched to the laboratory workflow. Modern spectrophotometers are usually equipped with touch screens and intelligent operating systems, supporting preset experimental protocols and cloud data management, which can significantly improve the efficiency of multi-user sharing devices. In terms of software, attention should be paid to whether it supports functions such as kinetic analysis, spectral overlay, automatic baseline correction, etc., and can be smoothly connected with the laboratory information management system (LIMS). In addition, the appropriate form is selected according to the measurement scenario: the portable model is suitable for field and field measurement; Benchtop equipment serves as the main force of the laboratory, providing more comprehensive performance; The online analyzer can be integrated into the production line for real-time feedback.
4. Comprehensive cost and after-sales support
Maximizing performance within budget is the ultimate goal of selection. Imported brands are usually mature in technology and high stability, but the price is more expensive; Domestic equipment is cost-effective, and the performance of some models is close to the import level, which is suitable for routine testing needs. When evaluating costs, consider long-term maintenance costs, choose modular design models to reduce maintenance difficulties and confirm the warranty period of core components (e.g., deuterium lamps, tungsten lamps). Comprehensive after-sales service should include on-site installation and commissioning, operation training, and regular software updates to extend the equipment life cycle. At the same time, it is important to confirm that the instrument complies with relevant industry standards (e.g., USP, EP, ASTM) or pharmacopoeia specifications, which is especially important for laboratories in regulated fields.
5. References
1. Key points for purchasing ultra-micro spectrophotometers. Unico (Shanghai) Instrument Co., Ltd. Technical Articles, 2025.
2. Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences. UV-Vis Spectrophotometer Inquiry Announcement, 2024.
3. How to Choose the Right Spectrophotometer for Your Lab: UV-Vis vs. IR vs. Fluorescence. Pgeneral, 2026.
4. UV-Vis spectrophotometer option single beam or dual beam? Shop according to your needs! Shanghai Youke, 2025.
5. Torontech. UV-Vis Spectrophotometer Selection Guide, 2025.
6. HunterLab. Guide to Color Spectrophotometers: What Tool Is Right for Your Application? 2024.