{"id":256,"date":"2019-08-13T17:26:15","date_gmt":"2019-08-13T09:26:15","guid":{"rendered":"https:\/\/www.bihec.com\/brimrose\/?p=256"},"modified":"2019-08-15T10:43:14","modified_gmt":"2019-08-15T02:43:14","slug":"brimrose-aotf-nir%e6%b3%95-%e8%bf%91%e7%ba%a2%e5%a4%96%e5%85%89%e8%b0%b1%e6%b3%95-%e6%b5%8b%e5%ae%9a%e7%81%b5%e8%8a%9d%e9%85%b8%e9%85%90%e4%b8%ad%e7%81%b5%e8%8a%9d%e9%85%b8%e7%9a%84%e5%90%ab%e9%87%8f","status":"publish","type":"post","link":"https:\/\/www.bihec.com\/brimrose\/brimrose-aotf-nir%e6%b3%95-%e8%bf%91%e7%ba%a2%e5%a4%96%e5%85%89%e8%b0%b1%e6%b3%95-%e6%b5%8b%e5%ae%9a%e7%81%b5%e8%8a%9d%e9%85%b8%e9%85%90%e4%b8%ad%e7%81%b5%e8%8a%9d%e9%85%b8%e7%9a%84%e5%90%ab%e9%87%8f\/","title":{"rendered":"Brimrose AOTF-NIR\u6cd5 \u8fd1\u7ea2\u5916\u5149\u8c31\u6cd5 \u6d4b\u5b9a\u7075\u829d\u9178\u9150\u4e2d\u7075\u829d\u9178\u7684\u542b\u91cf"},"content":{"rendered":"

AOTF-NIR<\/a>\u6cd5\u6d4b\u5b9a \u7075\u829d\u9178\u9150<\/a>\u4e2d\u7075\u829d\u9178\u7684\u542b\u91cf<\/p>\n

I.\u00a0 <\/u>\u603b\u7ed3<\/u><\/h1>\n
AOTF<\/a>\u7684\u539f\u7406\u662f\u57fa\u4e8e\u5149\u5728\u5404\u5411\u540c\u6027\u4ecb\u8d28\u4e2d\u7684\u58f0\u884d\u5c04\uff0c\u8be5\u88c5\u7f6e\u7531\u4e00\u4e2a\u538b\u7535\u4f20\u611f\u5668\u4e0e\u4e00\u4e2a\u53cc\u6298\u5c04\u4eea\u8fde\u63a5\u5728\u4e00\u8d77\u6784\u6210\uff0c\u5f53\u4f20\u611f\u5668\u88ab \u5e94\u7528<\/a>\u7684\u5c04\u9891\u4fe1\u53f7\u6fc0\u6d3b\u65f6\uff0c\u4f1a\u5728\u6676\u4f53\u4e2d\u4ea7\u751f\u58f0\u6ce2\u3002\u4f20\u64ad\u58f0\u6ce2\u4ea7\u751f\u4e86\u6298\u5c04\u7387\u7684\u5468\u671f\u6027\u8c03\u5236\uff0c\u8fd9\u63d0\u4f9b\u4e86\u4e00\u4e2a\u79fb\u52a8\u5149\u6805\uff0c\u5728\u9002\u5f53\u7684\u6761\u4ef6\u4e0b\uff0c\u4f1a\u884d\u5c04\u90e8\u5206\u5165\u5c04\u5149\u675f\u3002\u5bf9\u4e8e\u56fa\u5b9a\u58f0\u9891\uff0c\u7a84\u9891\u6bb5\u7684\u5149\u9891\u6ee1\u8db3\u5339\u914d\u6761\u4ef6\uff0c\u5e76\u7d2f\u79ef\u884d\u5c04\u3002\u968f\u7740RF\u9891\u7387\u7684\u53d8\u5316\uff0c\u5149\u5e26\u7684\u4e2d\u5fc3\u4e5f\u4f1a\u76f8\u5e94\u5730\u6539\u53d8\uff0c\u4ece\u800c\u4fdd\u6301\u76f8\u4f4d\u5339\u914d\u6761\u4ef6\u3002<\/p>\n
$\"\"$ <\/p>\n
The near infrared region of the spectrum extends from 800nm to 2500nm.\u00a0 The absorption bands that are most prominent in this region are due to overtones and combinations of the fundamental vibrations active in the mid-infrared region.\u00a0 The energy transitions are between the ground state and the second or third excited vibrational states.\u00a0 Because higher energy transitions are successively less likely to occur, each overtone is successively weaker in intensity.\u00a0 The energy required to reach the second or third excited state is approximately twice or three times that needed for a first order transition.\u00a0 The wavelength of absorption is inversely proportional to the energy, therefore the absorption bands occur at about half and one third the wavelength of the fundamental absorption.\u00a0 In addition to the simple overtones, combination bands also occur.\u00a0 These usually involve a stretch plus one or more bending of rocking modes.\u00a0 Many different combinations are possible and therefore the NIR<\/a> region is complex, with many band assignments unresolved.<\/p>\n
<\/p>\n
Near Infrared Spectroscopy is currently being used as a quantitative tool which relies on chemometrics to develop calibrations relating a reference analysis of the constituent to that of the NIR optical spectrum.\u00a0 The mathematical treatment of NIR data includes Multi Linear Regression (MLR), Principle Component Analysis (PCA), Principle Component Regression<\/p>\n
(PCR), Partial Least Squares (PLS) and discriminant analysis.\u00a0 All of these algorithms can be used singularly or in combination to yield the resultant goal of quantitative prediction and qualitative description of the constituents of interest in the sample.<\/p>\n
\n
Methodology<\/u><\/strong><\/li>\n<\/ol>\nIn the manufacturing process of phtalic anhydride the solid anhydride is grated into flakes by a rotating drum.\u00a0 Water is used to cool the drum and due to reasons inherent to the process, penetration of water into the phtalic anhydride occurs.\u00a0 Some anhydride reacts to form phtalic acid when water penetrates.\u00a0 The time that elapses from the onset of the penetration until detection is critical because the product being processed during that period is likely to be discarded.\u00a0 A reliable and fast determination of the onset of such an event can be extremely useful from an economic point of view.\u00a0 The AOTF-NIR Luminar<\/a> spectrometer can serve as a very fast, real-time, on-line detection system for such an occurrence.\u00a0 The phtalic anhydride has 2 C-O-C bonds in a pentagonal ring that disappear when it reacts with water. Two carboxylic groups are formed (HO-C=O) that give rise to absorption bands which do not naturally exist in the anhydride.\u00a0 Therefore, it is expected that phtalic acid should be detectable in low concentrations when mixed with the anhydride.\u00a0 It is possible that part or most of the water that penetrates will not react with the anhydride in a short time.\u00a0 However, it is expected that the 1950nm absorption band of the water will be detectable as soon as penetration occurs because it has a very large absorption coefficient.<\/p>\n
A Brimrose AOTF-NIR Luminar<\/a> Free Space spectrometer with a small area beam was used. The spectrometer is designed to operate between 1200nm and 2300nm. The scanning speed is 4000 wavelengths per second.\u00a0 200 scans were collected and averaged into one spectrum for each data point.\u00a0\u00a0 Acquisition time was about 14 seconds per spectrum.\u00a0 21 samples were prepared by blending varying amounts of phtalic acid and phtalic anhydride in a blender.\u00a0 The samples ranged from pure phtalic anhydride to 2% by weight of phtalic acid in increments of 0.1%.\u00a0 The blended samples were placed in polyethylene bags and stored in a dry desiccator.\u00a0 The bags were opened and a sample was poured into a small petri dish shortly before spectra collection.\u00a0 The sample was placed on the spectrometer support surface at a fixed distance from the main lens and the collection of spectra was done through the glass. The same dish was used for all the samples to minimize interference.\u00a0 The spectra were collected in transmission mode and processed into absorbance.<\/p>\n
III.\u00a0 Results<\/u><\/strong><\/p>\n
\n
Spectra<\/strong><\/li>\n<\/ol>\n
$\"\"$ <\/p>\n
\n
Regressions and Modeling<\/strong><\/li>\n<\/ol>\n
$\"\"$ <\/p>\n
The PLS 1 regression model correlating phtalic acid in phtalic anhydride to spectral data showed excellent results, especially for such a small sample set.\u00a0 Past experience has shown that using a sample set of 100 or more samples significantly increases the accuracy and robustness of any model.\u00a0 The correlation coefficients are a measure of the correlation between the calibration and validation sets and the numbers of 0.993 and 0.980 for the calibration and validation sets show that this model can accurately predict phtalic acid in phtalic anhydride from spectral data.<\/p>\n
PCA analysis was done on the spectral data and the scores plots below show PC1 vs. PC2<\/a> and PC3 vs. PC4.\u00a0 Principle components are a measure of how many iterations the model must do to explain the data and 5 were done for the PLS model.\u00a0 The results show that there is fairly good separation between the samples and that the spectral differences are large.<\/p>\n
$\"\"$ <\/p>\n
$\"\"$ <\/p>\n
\n
Conclusions and Recommendations<\/u><\/strong><\/li>\n<\/ol>\nThe results of this study clearly prove that identification and quantitative determination of the presence of small quantities of phtalic acid in phtalic anhydride is feasible using spectral data obtained from the Brimrose<\/a> AOTF-NIR Luminar Free Space spectrometer and a calibration model.\u00a0 The speed and insensitivity to mechanical vibrations of the spectrometer make it an ideal tool for a real-time on-line application for detection of the acid in the anhydride.\u00a0 Even if some of the penetrating water is unreacted, past experience has shown that the Brimrose AOTF-NIR spectrometer can easily detect changes in moisture and the same will hold true here.\u00a0 The results of the model were very good and they will be even better when a larger sample set is used for the calibration model.\u00a0 It is recommended to perform a test simulating the penetration of water in small quantities into anhydride.\u00a0 A method for conducting this test is to spray small quantities of water on the anhydride flakes.\u00a0 Spectra can be collected at varying time intervals.\u00a0 The consecutive spectra should show the progress of the acid level with exposure time.\u00a0 Several such samples should be prepared and they should all be sprayed with varying amounts of water.\u00a0 Quantitative analysis is not an absolute must for this application.\u00a0 Once a “normal” spectra is characterized by the PCA model, it is possible to define a “deviant” spectra that corresponds to a predetermined level of water, acid content, or a combination of both.\u00a0 These “deviant\u201d conditions can be used to trigger alarms or be used for some other means of process control once the conditions are identified by the system.\u00a0 It is concluded that a Brimrose AOTF-NIR spectrometer can determine the presence of small quantities of phtalic acid in phtalic anhydride.<\/p>\n
AOTF<\/a>\n Brimrose<\/a>\n PET\u9178\u503c<\/a>\n \u4fbf\u643a\u5f0f\u5149\u8c31\u4eea<\/a>\n \u4fbf\u643a\u5f0f\u8fd1\u7ea2\u5916<\/a>\n \u4fbf\u643a\u8fd1\u7ea2\u5916<\/a>\n \u5085\u91cc\u53f6\u7ea2\u5916\u5149\u8c31\u4eea<\/a>\n \u5206\u5b50\u91cf\u5728\u7ebf<\/a>\n \u542b\u6c34\u7387\u5728\u7ebf\u68c0\u6d4b<\/a>\n \u5728\u7ebf\u7f9f\u503c<\/a>\n \u624b\u6301\u5f0f\u5149\u8c31\u4eea<\/a>\n \u6d4b\u91cf\u7075\u829d\u9178<\/a>\n \u7075\u829d\u9178\u9150<\/a>\n \u7ea2\u5916\u5149\u8c31<\/a>\n \u7ea2\u5916\u5149\u8c31\u4eea<\/a>\n \u7ea2\u5916\u5149\u8c31\u5206\u6790\u4eea\u5668<\/a><\/div>","protected":false},"excerpt":{"rendered":"
AOTF-NIR\u6cd5\u6d4b\u5b9a\u7075\u829d\u9178\u9150\u4e2d\u7075\u829d\u9178\u7684\u542b\u91cf I.\u00a0 \u603b\u7ed3 AOTF\u7684\u539f\u7406\u662f\u57fa\u4e8e\u5149\u5728\u5404\u5411\u540c\u6027\u4ecb\u8d28\u4e2d\u7684\u58f0\u884d\u5c04\uff0c\u8be5\u88c5\u7f6e\u7531\u4e00\u4e2a\u538b\u7535\u4f20\u611f\u5668\u4e0e\u4e00\u4e2a\u53cc\u6298\u5c04\u4eea\u8fde\u63a5\u5728\u4e00\u8d77\u6784\u6210\uff0c\u5f53\u4f20\u611f\u5668\u88ab\u5e94\u7528\u7684\u5c04\u9891 <\/p>\n","protected":false},"author":19,"featured_media":151,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[15],"tags":[33,34,47,53,62,61,55,49,40,42,59,136,137,50,51,57],"_links":{"self":[{"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/posts\/256"}],"collection":[{"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/comments?post=256"}],"version-history":[{"count":0,"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/posts\/256\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/media\/151"}],"wp:attachment":[{"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/media?parent=256"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/categories?post=256"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bihec.com\/brimrose\/wp-json\/wp\/v2\/tags?post=256"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}