Computational Screening of Environmental Proxies in Spectrometric Patterns from Humic Acids
It is well known that humic acids (HAs) have a complex heterogeneous composition which depends not only on the precursor organic constituents but to large extent on the environmental factors in the soil system.In this study,an ‘omic approach was carried out taking advantage of the information from different data matrices obtained by analytical pyrolysis of HAs.It was intended to readily infer tentative environmental information avoiding complex,time-consuming spectral interpretations and supervised data processing.This approach is based on comparing the information extracted from data tables with compounds assemblages after HA degradation by i) multivariate data treatments,mainly multidimensional scaling (MDS) and correspondence analysis,ii) partial least squares (PLS) regression where the variable importance for projection (VIP) method was applied in order to identify the more informative chromatographic peaks and iii) PLS-VIP method applied to ‘rebuilt pyrolysis-mass spectra i.e.,to arrays consisting of one average mass spectra (2-60 min) of the total ion gas chromatogram.When the results obtained from approach (iii) were compared with those from approaches (i) and (ii),we realize the possibility for a tentative prediction of the relative amounts of almost all major families of degradation compounds and large number of individual compounds.Apart from this,a series of characteristics of HAs and whole soils (e.g.,aromaticity,respiratory activity,extent of lignin alteration...) could be predicted with a variable success,not requiting previous interpretation of the mass spectra or integration of chromatographic peaks.The PLS-VIP plots in approach (iii) with the same format of a typical mass spectra-lead to conclusions similar to MDS (used for variables ordination) or simple and multiple regressions,and illustrates the ion patterns relevant as regards to predicting soil and HA characteristics.
Humic substances Degradation methods Mass spectrometry Multidimensional scaling Partial least squares regression Variable importance for projection
G.Almendros Z.Hemández J.Sanz F.J.Gonzátlez-Vila H.Knicker J.A.González-Pérez
MNCN-CSIC.Serrano 115B 28006 Madrid,Spain Departrnent of Analytical Chemistry,University ofLa Laguna,38206 La Laguna,Spain Institute of General Organic Chemistry,CSIC,Juan de la Cierva 3,28006 Madrid,Spain IRNAS-CSIC.Avda.Reina Mercedes,10,41012-Seville,Spain
国际会议
the 16th Meeting of the International Humic Substances Society (第十六届国际腐殖物质学会大会(IHSS 16))
杭州
英文
138-140
2012-09-09（万方平台首次上网日期，不代表论文的发表时间）