Research On Multi-band Near-infrared Liquid Component Detection Method

Liquid component testing is widely used in industrial production,pharmaceutical production and food production industries.Traditional liquid component testing methods mainly use hydrometer method,density bottle method,refractometer method and chemical oxidation method,but these traditional methods are inspecting.When the temperature is strict,it is difficult to achieve on-line detection,and the chemical method will destroy the test sample,and the detection time is longer.With the development of the times,near-infrared spectroscopy technology has become more and more mature.Many people have begun to study the use of near-infrared spectroscopy to detect liquid components,and on this basis,the detection devices are being explored,but the existing detection devices still have prices.Expensive,complicated operation and so on.Therefore,it is particularly important to propose a new liquid component detection method to realize miniaturization,low cost and intelligence of the detection device.The traditional liquid component detecting device generally has certain limitations.Taking the alcohol concentration detecting device as an example,the simple alcohol solution detecting device has a small detection range and a large sample amount;and the sophisticated detecting device often has high price and complicated operation.problem.This study explores the way to solve this problem,designs the overall scheme of the detection device,and describes the liquid detection pool and peripheral structure design,circuit design and software program development of the device.The inexpensive LED light source and unique liquid pool structure design realize the low cost and miniaturization of the device.The detecting device uses the STM32F373 single-chip microcomputer as the control chip,and is composed of a light source module,a liquid pool module,a detecting module and a control module.The laboratory calibration test,performance test,on-site sampling test and analysis were carried out on the alcohol aqueous solution concentration detecting device,and the solution was scanned by nearinfrared spectroscopy to establish a model for comparison.The abnormal data is removed from the collected data by Mahalanobis distance,and then the sample set is divided by SPXY(Sample set Partitioning based on joint XY distance)algorithm.Finally,the PLS-DA(Partial Least Squares)algorithm is used to establish the relationship between the concentration of alcohol solution and the absorbance.model.The results show that the device achieves high measurement accuracy,and its prediction correlation coefficient is 0.9927,and the predicted root mean square error is 0.0256.The stability of the device was tested and sampled 8 times in 240 minutes with a standard deviation of 0.44%.The standard deviation of sampling for 10 consecutive days was 3.03%.In the actual sampling test,10 samples were selected,and the average relative deviation between the standard value and the measured value of the test sample was 5.1%.The experimental results show that the multi-band liquid component detection device basically meets the requirements for the detection accuracy of the alcohol aqueous solution sample.The multi-band liquid component detection method proposed in this paper is feasible and superior to the single-feature wavelength-based detection method.At the same time,this study provides a reference for the design and development of practical liquid component testing instruments.