1. The retention time of the main peak of the ultraviolet spectrogram should be greater than 2T0 (injection peak time) and less than 4/5 of the total running time.
2. The absorption wavelength of ultraviolet spectrum is subject to the wavelength specified by customers (generally 220nm). Weak ultraviolet samples (ultraviolet absorption is at 220 nm, and mass spectrum signal is relatively strong) can be provided by ELSD spectrum or according to customer requirements.
3. Generally, the absorption of the main peak of ultraviolet spectrum should be higher than 100mau. For samples with good signal-to-noise ratio, the peak height can be appropriately reduced to more than 50mau, and all visible ultraviolet peaks that are still qualified after integration can be regarded as qualified.
4. In the ultraviolet spectrum, the theoretical plate number of the main peak is above 10000 (that is, the peak width is less than 0.5 minutes), and the peak symmetry factor should be 0.9- 1.2 (that is, the symmetry is good).
5.MS spectrum should ensure that the ion peak of excimer is visible, and the other peaks are dimerization peaks, reasonable fragments or addition peaks.
6.MS range: usually between 100 and 1000. For samples with small or large molecular weight, the MS range should be adjusted to ensure that the maximum value exceeds 2M+23 and the minimum value is less than M/2.
7. For impurities with UV integral over 2%, if the MS of impurities is consistent with the main peak, it is necessary to check whether there are isomers in the structure. Only when the customer confirms the existence of isomers and agrees that the product can be delivered in combination with purity can it be judged as qualified, otherwise, the structure should be re-separated or determined by other means such as nuclear magnetic resonance.
origin
In the past, in order to successfully transmit learning content in the media, special tools were needed to edit learning content. For example, Authorware or DreamWeaver can make online courses, and Word and PowerPoint can also make paper materials. Course developers either need to learn specialized tools or work with programmers with these skills. The content is developed from one course to another, which requires a lot of development and testing.
LCMS separates the content from the transmission medium. Content is generated at one time and spread in many ways. LCMS also eliminates the need for professional program skills and allows editors to fill in pre-programmed program templates. Because content is created in the form of small objects, content developers can reuse the content used by others, saving development time, just like providing consistent news for learners.