CHEMOMETRIC CHARACTERIZATION OF RESINS AND COATINGS USING NEAR INFRARED SPECTROSCOPY

Namen diplomskega dela je preučiti možnost zamenjave klasičnih analiznih metod z metodo NIR. Eksperimentalni del smo izvajali na NIR spektrofotometru NIRFlex N — 500, proizvajalca BUCHI, Švica, podprtim s programsko opremo NIRcal V 5.2. Klasične analizne metode smo izvajali v skladu z veljavnimi ISO standardi. Kvantitativna NIR kalibracija je sestavljena iz štirih osnovnih korakov: izbira reprezentativnega kalibracijskega niza, pridobivanje in določevanje referenčnih vrednosti spektrov, povezava vrednosti spektrov z referenčnimi vrednostmi in validacija izdelane metode. Vsem vzorcem smo z refleksijsko sondo Fiber optic soldis z nastavkom za tekočine, povezano z NIR inštrumentom, posneli NIR spektre. Za izdelavo kvantitativnih kalibracij smo uporabili matematični postopek metode delnih najmanjših kvadratov PLS (ang. Partial Least Squares). Za vse izvedene kvantitativne kalibracije smo kot validacijsko metodo uporabili VS validacijski niz. Za ugotavljanje primerljivosti klasičnih metod, z metodo NIR pa smo uporabili signifikantni parni t-test. Bližnja rdeča spektroskopija se je izkazala kot alternativna metoda klasičnim analiznim metodam. Bližnja infrardeča spektroskopija je enostavna za uporabo, hitra, nedestruktivna ter prijazna ljudem in okolju. Z njo prihranimo čas in stroške, ki nastanejo z nakupom reagentov.The scope of the research work was to examine the possibility of replacing conventional analytical methods with NIR method. Experimental work was performed on NIR spectrophotometer NIRFlex N – 500 BUCHI, Switzerland. Conventional classical analytical methods were carried out in accordance with valid ISO standards. Each sample was recorded with reflection probe NIR spectra. Quantitative NIR calibration consists of four basic steps: selection of a representative calibration sample set, spectra acquisition and determination of reference values, multivariate modeling to relate the spectral variations to the reference values of the analytical target property and validation of the method. Partial Least Squares PLS was used for developing of NIR models. Results of NIR models were tested with significant paired t-test. Near infrared spectroscopy has proven to be an alternative method to conventional, classical analytical methods. Near infrared spectroscopy is an analytical technique which is simple to use, fast and non-destructive. It is an environmentally and user friendly technique. NIRS method is saving time of analyses and reducing the cost od reagents