METHOD OF IDENTIFYING AND PREDICTING P-ALKYL RADICALS OF O-ALKYLALKYLFLUOROPHOSPHONATES HOMOLOGUES Russian patent published in 2019 - IPC G01N21/35 

FIELD: physics.

SUBSTANCE: invention relates to analytical studies on determining the structure of organic compounds by infrared spectrometry and can be used for accurate identification and prediction of P-alkyl radical in homologues of O-alkylalkylfluorophosphonates. Disclosed method of identifying and predicting P-alkyl homologue radicals of O-alkylalkylfluorophosphonates by their infrared spectra of the middle region of range (1,330–1,240 cm^-1) of the condensed phase consists in determining a set of spectral features-predictors, which enable to classify them by type of P-alkyl radical. Pairs of values "wave number – optical density" of the spectrum of the analysed sample, which is presented in a numerical format, are sorted by descending values of the wave number and the spectrum is converted to a first-order derivative by formula A'(λ_i)=(A(λ_i+1)-A(λ_i))/Δλ, (λ_i>λ_i+1 cm^-1), where A'(λ_i) is the first derivative of optical density on wavenumber λ, A(λ_i) is optical density at i-th value of wave number λ, Δλ=(λ_i+1 – λ_i) is a spectrum sampling step. At partial intervals (dt) 1,320–1,310 cm^-1, 1,300–1,290 cm^-1, 1,270–1,260 cm^-1, 1,260–1,250 cm^-1 derivative of optical density is measured by wave number and values of prognostic parameter G are calculated by formula

where

G_j – standardized sum of values of first derivative of optical density by wavenumber on j-th interval, j – number of partial interval dt (dt=10 cm^-1), A'(λ_i) – i-th value of first derivative of optical density on wavenumber on j-th partial interval dt, k is number of derivative values on j-th partial interval dt, including values on its boundaries, M_Σ – arithmetic mean of total values (accumulated for each point of interval dt) values of first derivative on j-th partial interval, S_Σ is the standard deviation of the total (accumulated for each point of the interval dt) values of the first derivative on the j-th partial interval. Values of the parameter G are used as predictors for calculating classification values by classification functions obtained as a result of discriminator analysis on a training sample of reference spectra of O-alkylalkylfluorophosphonates of one spectral resolution; structure of the P-alkyl radical of the test compound is established by the highest classification indices. P-alkyl radicals of homologues of O-alkylalkylfluorophosphonates are predicted by distribution of training sample objects in space of discriminant functions.

EFFECT: increased reliability, efficiency and cost effectiveness at control of toxic chemicals.

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