Rapid test strips are a common tool used to initially detect the presence of certain substances, but they usually cannot accurately determine the purity of illegal drugs. These test strips are usually based on chemical reactions, indicating their presence by color changes with specific substances. However, this method has the following limitations： 1. **Qualitative rather than quantitative**: Test strips usually can only detect the presence of a certain substance, but cannot provide accurate information about its concentration or purity. 2. **Limited specificity**: Test strips may react to a variety of substances, resulting in false positives or false positives. For example, certain legal drugs or impurities may also react with test strips and interfere with test results. 3. **Unable to distinguish ingredients**: Illegal drugs may contain multiple ingredients or additives. Test strips usually cannot distinguish these ingredients, so it is impossible to accurately judge the purity. 4. **Operating error**: When using test strips, improper operation or environmental factors (such as temperature and humidity) may also affect the accuracy of the test results. ### More accurate detection method If you need to accurately judge the purity of illegal drugs, you usually need to use more professional analytical methods, such as： -**Gas chromatography-mass spectrometry (GC-MS)**: It can separate and identify different components in the sample and provide quantitative analysis. -**High performance liquid chromatography (HPLC)**: Used to analyze the components and their concentrations in complex mixtures. -**Infrared spectroscopy (IR)**: Identify the composition of a substance by analyzing its infrared absorption spectrum. ### Safety tips The use and testing of illegal drugs involves serious legal and health risks. Regardless of the purpose, exposure to or use of illegal drugs is a very dangerous behavior that can lead to serious health problems, addiction and even death. If you or someone you know is struggling with substance abuse, please seek professional help immediately. **Please always put health and safety first, and comply with laws and regulations. **