Albumin and γ-globulin concentrations in subcutaneous adipose tissues (SAT) have been quantified by multivariate regression based on admittance relaxation time distribution (mraRTD) under the fluctuated background of sodium electrolyte concentration. The mraRTD formulates P = Ac + Ξ (P: peak matrix of distribution function magnitude ɣP and frequency τP, c: concentration matrix of albumin cAlb, γ-globulin Gloc, and sodium electrolyte Nac, A: coefficient matrix of a multivariate regression model, and Ξ: error matrix). The mraRTD is implemented by two processes which are: 1) the training process of A through the maximum likelihood estimation of P and 2) the quantification process of cAlb, Gloc, and Nac through the model prediction. In the training process, a positive correlation is present between cAlb, Gloc, and Nac to ɣP1 at τP1= 0.1 as well as ɣP2 at τP2= 1.40 µs as under a fixed concentration of proteins solution into a porcine SAT (cAlb = 0.800-2.400 g/dL, Gloc = 0.400-1.200 g/dL and Nac = 0.700-0.750 g/dL). The mraRTD method quantifies cAlb, Gloc, and Nac in SAT with an absolute error of 33.79%, 44.60%, and 2.18%, respectively.
Keywords: Impedance spectroscopy; Multivariate regression; Protein concentrations quantification; Relaxation times distribution.
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