	US 11,913,875 B2
	Method for the identification of an incorrectly calibrated or non-calibrated infrared spectrometer
Ingolf Reimann, Reinheim (DE); Joachim Reising, Kleinostheim (DE); and Christoph Mueller, Offenbach am Main (DE)
Assigned to Evonik Operations GmbH, Essen (DE)
Appl. No. 17/311,911
Filed by Evonik Operations GmbH, Essen (DE)
PCT Filed Dec. 13, 2019, PCT No. PCT/EP2019/085010 § 371(c)(1), (2) Date Jun. 8, 2021, PCT Pub. No. WO2020/126869, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 18212853 (EP), filed on Dec. 17, 2018.
Prior Publication US 2022/0026350 A1, Jan. 27, 2022
Int. Cl. G01N 21/27 (2006.01); G01J 3/28 (2006.01)

CPC G01N 21/274 (2013.01) [G01J 3/28 (2013.01); G01J 2003/2859 (2013.01); G01J 2003/2879 (2013.01)]

14 Claims

1. A computer-implemented method for identifying an incorrectly calibrated or non-calibrated infrared spectrometer, the computer-implemented method comprising:

a) recording an infrared spectrum of a sample with a first infrared spectrometer to provide a sample infrared spectrum,

b) recording an infrared spectrum of the same sample as in a) with a second infrared spectrometer to provide a reference infrared spectrum, wherein said second spectrometer is a correctly calibrated infrared spectrometer,

b′) providing a reference spectrum of the same sample as in a), wherein said reference spectrum was recorded on a second infrared spectrometer, which is a correctly calibrated spectrometer,

c) determining a difference between the wavelength of each extreme point in the sample spectrum of a) and the wavelength of the same extreme point(s) in the reference spectrum of b) or b′), comprising:

c1) determining the wavelengths of each extreme point in the sample spectrum of a), and in the reference spectrum of b) or b′), wherein c1) further comprises taking the first and/or second derivative of the sample spectrum and of the reference spectrum,

c2) assigning the wavelengths determined in c1) in the order of their appearance in the sample spectrum of a) to the wavelengths determined in c1) in the order of their appearance in the reference spectrum of b) or b′) to provide pairs of matched wavelengths, and

c3) calculating index ratios for each pair of matched wavelengths by dividing the wavelengths of said pair, wherein a ratio different from 1 indicates a difference between the wavelengths of each pair,

c4) generating arrays of ratios for each of the index ratios of c3) and the two wavelengths forming said ratio, and

c5) storing the arrays of ratios of c4) in a database, data storage or cloud together with the identification or serial number of the infrared spectrometer of a),

d) indicating the infrared spectrometer of a) as incorrectly calibrated or non-calibrated, when at least one difference was determined in c),

e) recording an infrared spectrum of a sample on an incorrectly calibrated or non-calibrated infrared spectrometer to provide an infrared spectrum of said sample, wherein said sample is identical or different from the sample of a),

f) identifying the infrared spectrometer of e) by its identification or serial number,

g) loading the arrays of ratios obtained for the infrared spectrometer of e) in c5) from a database, data storage or cloud,

h) multiplying the index ratio of each array of ratios of iii) with the corresponding wavelength of an extreme point in the spectrum of e) to provide corrected wavelengths of the extreme points, and

i) providing a corrected infrared spectrum with the corrected wavelengths of the extreme points of h).