當您在選購防曬產(chǎn)品時，你一定關(guān)注過SPF、PA+、臨界波長（CW）或Boots星級這些標識。這些看似簡單的數(shù)字和符號，實際上是經(jīng)過一系列嚴格、標準化測試得出的科學結(jié)論。

「防曬功效測試的國際標準體系」

目前行業(yè)普遍采用的標準包括：

·ISO 24444：防曬因子（SPF）的體內(nèi)測定

·ISO 24442：UVA防護（UVA-PF）的體內(nèi)測試方法

·ISO 24443：UVA防護（UVA-PF）的體外測試方法

·ISO 23675：防曬因子（SPF）的體外測定方法

·ISO 23698：用漫反射光譜法測量防曬效果

除了ISO標準外，行業(yè)還廣泛采用COLIPA（現(xiàn)為Cosmetics Europe）指南和Boots Star Rating體系，這些標準為防曬產(chǎn)品的功效評價提供了完整的技術(shù)框架。

「測試方法分類與應(yīng)用」

化妝品行業(yè)的防曬功效測試主要分為兩大類：體內(nèi)測試和體外測試。

體內(nèi)測試：以人體為測試對象，直接在志愿者皮膚上評估防曬產(chǎn)品防止曬紅（評估SPF值）或曬黑（評估PA等級）的能力。這種方法被認為是傳統(tǒng)的“金標準"，但對人體存在一定的損傷且可能有致癌的風險，而且存在成本高昂、周期長、受個體差異影響大等局限性。

體外測試：利用專業(yè)的實驗室儀器，模擬紫外線對涂有樣品的特定基材的照射過程，通過測量樣品的紫外線透射率或吸光度，再經(jīng)由公式和標準計算出防曬指數(shù)。

體外測試具有便捷、成本可控且不受人體變異因素影響等優(yōu)勢，正在成為研發(fā)和質(zhì)量控制中重要的一環(huán)。

「防曬測試儀器：SPF-290AS紫外透過率/防曬指數(shù)分析儀」

在體外測試中，SOLAR LIGHT的SPF-290AS紫外透過率/防曬指數(shù)分析儀，可用于防曬產(chǎn)品的功效測試。該儀器通過測量樣品在紫外線波段的透射率來評估防曬效果。

SPF-290AS的光學系統(tǒng)采用功率穩(wěn)定的150W無臭氧氙燈，配合光電倍增管（PMT）探測器，能夠測量290nm~400n波長范圍內(nèi)的光信號變化。儀器配備的自動化X-Y樣品平臺可以實現(xiàn)多點定位和掃描，完成一次全波段測量的最短時間為24秒。

該儀器的測試方法符合ISO 23675、ISO 24443等國際標準要求，可以計算SPF、臨界波長（CW）、UVA-PF等參數(shù)。軟件支持用戶根據(jù)需求調(diào)整測試參數(shù)。

在樣品處理方面，對于乳液、膏霜等樣品，可以使用注射器將樣品涂布在特定粗糙度的PMMA板上進行測試；對于噴霧類產(chǎn)品，可以采用石英板作為測試載體。

「關(guān)于SPF-290AS，你可能想了解這些」

1）它的測試結(jié)果準嗎？和體內(nèi)實驗對比怎么樣？

它的準確性經(jīng)過了大量驗證。從長期的使用情況和客戶反饋來看，儀器測量的結(jié)果與人體皮膚測試的結(jié)果非常接近。

2）SPF-290AS可以直接代替體內(nèi)測試嗎？

很遺憾，目前還不行。根據(jù)像美國FDA這樣的法規(guī)要求，產(chǎn)品最終標注的SPF值必須基于體內(nèi)測試。但SPF-290AS在配方篩選和優(yōu)化環(huán)節(jié)能節(jié)省大量前期的時間和資金投入。

3）為什么是檢測290~400nm這個范圍？

這是防曬的標準范圍。這個波長區(qū)間正好覆蓋了紫外線中對我們皮膚有影響的UVA和UVB全部波段，是國際法規(guī)和科學界的計算防曬指數(shù)的基準。

4）SPF-290AS的光源有什么特別之處？

它采用連續(xù)紫外光源，盡可能模擬了真實的太陽光。這種設(shè)計更接近體內(nèi)測試的環(huán)境和我們在戶外接觸到的日光，使得測量結(jié)果更具實際參考意義。

5）測出來的數(shù)據(jù)方便做進一步分析嗎？

非常方便。儀器的SPF數(shù)據(jù)采用標準ASCII格式存儲，常用軟件如Excel、Access都可讀取。

6）該怎么涂抹樣品呢？

操作流程很直觀：先對專用的測試板（如PMMA板）進行一次“空白"測量作為基準。然后，將定量的防曬產(chǎn)品以點涂的形式均勻涂開在板上，形成一層厚度一致的薄膜。WinSPF軟件的在線幫助欄目詳細說明了操作步驟。

7）儀器工作時會產(chǎn)生有害的臭氧嗎？

針對設(shè)備可能產(chǎn)生臭氧的疑問，進行了嚴格的驗證。盡管部分電子設(shè)備在運行時確實會產(chǎn)生微量臭氧，但SPF-290AS分析儀所產(chǎn)生的臭氧濃度，低于當前已知的任何測試方法的檢測下限。

使用Lab Safety Supply的專業(yè)臭氧檢測工具（具體貨號為1A-5155-6和1A-5154-6）進行了實際測試。測試過程中，技術(shù)人員讓設(shè)備連續(xù)運行數(shù)小時，并在其旁邊進行監(jiān)測，檢測工具均未顯示出存在臭氧的反應(yīng)。

需要說明的是，此次所用檢測工具的靈敏度為：在15分鐘的檢測周期內(nèi)，可檢測到0.1ppm的臭氧。測試結(jié)果遠低于此限值，充分證明了設(shè)備使用的安全性。

上海微譜檢測使用SPF-290AS進行了測試：使用兩個防曬標準品進行方法驗證，測試結(jié)果均符合SPF標準品要求范圍

上海微譜檢測使用SPF-290AS進行了測試：不同類型得防曬產(chǎn)品體內(nèi)、體外檢測的一致性較好

「測試儀器的應(yīng)用價值」

在化妝品研發(fā)過程中，使用SPF-290AS這類儀器可以幫助研發(fā)人員測試不同配方的防曬性能，為配方優(yōu)化提供數(shù)據(jù)支持。

在生產(chǎn)質(zhì)量控制環(huán)節(jié)，通過對產(chǎn)品進行定期測試，可以確保不同批次產(chǎn)品防曬效果的穩(wěn)定性。基于儀器測試獲得的數(shù)據(jù)，可以為產(chǎn)品功效宣稱提供技術(shù)支持，有助于企業(yè)應(yīng)對市場監(jiān)督和質(zhì)量審核。

「結(jié)語」

防曬功效的測試需要遵循科學的方法和標準規(guī)范。從體內(nèi)測試到體外測試，國際標準體系為防曬產(chǎn)品的功效評價提供了完整的技術(shù)框架。SOLAR LIGHT的SPF-290AS提供了一種技術(shù)選擇，可以用于防曬產(chǎn)品的研發(fā)和質(zhì)量控制。

作為Solar Light的合作伙伴，我們致力于為化妝品行業(yè)提供防曬檢測技術(shù)支持。如需了解更詳細的儀器信息或測試方法，歡迎與我們聯(lián)系！

How is Sun Protection Factor (SPF) Measured? Understanding International Standards and Testing Instruments

When selecting sun protection products, you have likely noticed labels such as SPF, PA+, Critical Wavelength (CW), or Boots Star Rating. These seemingly simple numbers and symbols are, in fact, scientific conclusions derived from a series of rigorous and standardized tests.

「International Standard System for Sun Protection Efficacy Testing」

The standards currently widely adopted in the industry include:

·ISO 24444: In vivo determination of sun protection factor (SPF)

·ISO 24442: In vivo UVA protection (UVA-PF) test method

·ISO 24443: In vitro UVA protection (UVA-PF) test method

·ISO 23675: In vitro determination of sun protection factor (SPF)

·ISO 23698: Measurement of sunscreen efficacy by diffuse reflectance spectroscopy

In addition to ISO standards, the industry also widely adopts the COLIPA (now Cosmetics Europe) guidelines and the Boots Star Rating system. These standards provide a complete technical framework for evaluating the efficacy of sun protection products.

「Classification and Application of Testing Methods」

Sun protection efficacy testing in the cosmetics industry is mainly divided into two categories: in vivo testing and in vitro testing.

In vivo testing: Uses human subjects to directly evaluate the ability of a sun protection product to prevent sunburn (assessing SPF value) or tanning (assessing PA grade) on volunteers' skin. This method is considered the traditional "gold standard." However, it poses some potential harm and carcinogenic risk to humans, along with limitations such as high cost, long cycles, and significant influence from individual variations.

In vitro testing: Utilizes specialized laboratory instruments to simulate the process of ultraviolet (UV) radiation on specific substrates coated with the sample. The sun protection factor is calculated via formulas and standards by measuring the sample's UV transmittance or absorbance.

In vitro testing offers advantages such as convenience, controllable costs, and freedom from human variability factors. It is becoming an indispensable part of research & development and quality control.

「Sun Protection Testing Instrument: Model SPF-290AS Automated UV Transmittance / SPF Analyzer」

In in vitro testing, SOLAR LIGHT's SPF-290AS (Automated UV Transmittance / SPF Analyzer) can be used for efficacy testing of sun protection products. This instrument evaluates sun protection effectiveness by measuring the sample's transmittance in the ultraviolet wavelength band.

The optical system of the SPF-290AS uses a 150W ozone-free xenon lamp with stable power output, coupled with a photomultiplier tube (PMT) detector, capable of measuring light signal changes in the 290nm to 400nm wavelength range. The instrument's automated X-Y sample stage enables multi-point positioning and scanning, with a minimum time of 24 seconds to complete a full spectrum measurement.

The testing methodology of this instrument complies with international standard requirements such as ISO 23675 and ISO 24443, and can calculate parameters like SPF, Critical Wavelength (CW), and UVA-PF. The software allows users to adjust testing parameters as needed.

Regarding sample handling, for samples like emulsions and creams, a syringe can be used to apply the sample onto a PMMA plate with specific roughness for testing. For spray products, a quartz plate can be used as the test substrate.

「Things You Might Want to Know About the SPF-290AS」

1)  How accurate are its test results? How do they compare to in vivo tests?

Its accuracy has been extensively validated. Based on long-term usage and customer feedback, the results measured by the instrument are very close to those from human skin tests.

2)  Can the SPF-290AS completely replace in vivo testing?

Unfortunately, not yet. According to regulatory requirements like those from the U.S. FDA, the final labeled SPF value of a product must be based on in vivo testing. However, the SPF-290AS can save significant upfront time and financial investment during the formulation screening and optimization stages.

3)  Why is the detection range 290~400nm?

This is the standard range for sun protection testing. This wavelength interval precisely covers both UVA and UVB bands of ultraviolet radiation that affect our skin. It is the baseline recognized by international regulations and the scientific community for calculating sun protection factors.

4)  What is special about the SPF-290AS light source?

It uses a continuous UV light source, simulating real sunlight as closely as possible. This design more closely resembles the environment of in vivo testing and the sunlight we are exposed to outdoors, making the measurement results more practically meaningful.

5)  Is the measured data convenient for further analysis?

Very convenient. The instrument's SPF data is stored in standard ASCII format, readable by common software like Excel and Access.

6)  How should the sample be applied?

The procedure is straightforward: First, perform a "blank" measurement on the dedicated test plate (e.g., PMMA plate) as a baseline. Then, evenly spread a quantified amount of the sun protection product in a dotted pattern on the plate to form a film of consistent thickness. The online help section of the WinSPF software details the operating steps.

7)  Does the instrument produce harmful ozone during operation?

Rigorous verification was conducted regarding concerns about potential ozone generation. While some electronic devices can produce trace amounts of ozone during operation, the ozone concentration generated by the SPF-290AS analyzer is below the detection limit of any currently known testing method.

Practical tests were performed using professional ozone detection tools from Lab Safety Supply (specific catalog numbers: 1A-5155-6 and 1A-5154-6). During testing, technicians operated the device continuously for several hours while monitoring beside it. The detection tools showed no indication of ozone presence.

It should be noted that the sensitivity of the detection tools used is: they can detect 0.1 ppm of ozone within a 15-minute detection cycle. The test results were well below this limit, fully demonstrating the safety of the device.

Shanghai Weipu Testing used the SPF-290AS to conduct testing: two sunscreen standards were used for method validation, and the test results of both met the required range for SPF standards.

Shanghai Weipu Testing used the SPF-290AS to conduct testing: the consistency between in vivo and in vitro testing for different types of sunscreen products was good.

「Application Value of Testing Instruments」

During cosmetic product development, using instruments like the SPF-290AS can help R&D personnel test the sun protection performance of different formulations, providing data support for formulation optimization.

In production quality control, regular testing of products can ensure the stability of sun protection efficacy across different batches. Data obtained from instrument-based testing provides technical support for product efficacy claims, helping companies respond to market supervision and quality audits.

「Conclusion」

Testing sun protection efficacy requires adherence to scientific methods and standard specifications. From in vivo to in vitro testing, the international standard system provides a complete technical framework for evaluating the efficacy of sun protection products. SOLAR LIGHT's SPF-290AS offers a technological option that can be used in the research, development, and quality control of sun protection products.

As a partner of Solar Light, we are committed to providing technical support for sun protection testing to the cosmetics industry. If you need more detailed information about the instrument or testing methods, please feel free to contact us!