ABSTRACT
Objective:To analyze the related substances in the domestic products of minoxidil and minoxidil gel for the purpose of standard improvement. Methods:An HPLC-Q-TOF-MS method was developed. The test was performed on a Thermo Scientific Accu-core C18 column (100 mm × 2. 1 mm, 2. 6 μm) with a mobile phase of acetonitrile-water (7:93) (containing 0. 1% formic acid) at a flow rate of 0. 2 ml·min-1 , the detection wavelength was 230 nm. The full scan and two stage scanning was employed for detection with ESI source positive ion mode. The mass scan range was m/z 50-500. Results:14 related substances were separated and detected under the established HPLC-Q-TOF-MS condition. The structures and resource of 8 related substances were analyzed preliminarily. Conclusion:The HPLC-Q-TOF-MS technology has been proved to be effective in separation and identification of the related substances in minoxidil and minoxidil gel. The results were useful for quality control.
ABSTRACT
Objective To find a useful index for real-time detecting of speech endpoint and improving the performance of speech processing under low SNR by analyzing fluctuation complexity of speech signals. Method The influence of state space partition method, window size and partition numbers on detecting performance was analyzed. The comparison experiments of speech signals corresponding to different SNR and noise type was designed using the measure of complexity behaviors based on the information gain.Result It was found that fluctuation complexity was more effective in detecting low-SNR speech than spectral entropy. Conclusion Fluctuation complexity is a valid feature to make speech/non-speech decision for the low SNR cases. The presented method can achieve robust performance and has a good real-time behavior.