title: Analysis of petroleum contaminated soils by spectral modeling and pure response profile recovery of n-hexane.
abstract: This pilot study compared penalized spline regression (PSR) and random forest (RF) regression using visible and near-infrared diffuse reflectance spectroscopy (VisNIR DRS) derived spectra of 164 petroleum contaminated soils after two different spectral pretreatments [first derivative (FD) and standard normal variate (SNV) followed by detrending] for rapid quantification of soil petroleum contamination. Additionally, a new analytical approach was proposed for the recovery of the pure spectral and concentration profiles of n-hexane present in the unresolved mixture of petroleum contaminated soils using multivariate curve resolution alternating least squares (MCR-ALS). The PSR model using FD spectra (r(2) = 0.87, RMSE = 0.580 log10 mg kg(-1), and residual prediction deviation = 2.78) outperformed all other models tested. Quantitative results obtained by MCR-ALS for n-hexane in presence of interferences (r(2) = 0.65 and RMSE 0.261 log10 mg kg(-1)) were comparable to those obtained using FD (PSR) model. Furthermore, MCR ALS was able to recover pure spectra of n-hexane.
authors.affiliation: Ramakrishna Mission Vivekananda University, Kolkata 700103, India.
authors.forename: Somsubhra
authors.initials: S
authors.lastname: Chakraborty
authors.affiliation: Department of Plant and Soil Science, Texas Tech University, Box 42122, Lubbock, TX 79409, USA. Electronic address: david.weindorf@ttu.edu.
authors.forename: David C
authors.initials: DC
authors.lastname: Weindorf
authors.affiliation: Department of Experimental Statistics, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.affiliation: Ramakrishna Mission Vivekananda University, Kolkata 700103, India.
authors.forename: Md Nasim
authors.initials: MN
authors.lastname: Ali
authors.affiliation: Soil Testing Laboratory, Kalimpong 734301, India.
authors.forename: K
authors.initials: K
authors.lastname: Majumdar
authors.affiliation: National Institute of Research on Jute and Allied Fibre Technology, Kolkata 700040, India.
authors.forename: D P
authors.initials: DP
authors.lastname: Ray
mesh_terms: D004784:Environmental Monitoring; D006586:Hexanes / Q000032:analysis* / Q000737:chemistry; D016018:Least-Squares Analysis; D008956:Models, Chemical; D010578:Petroleum / Q000032:analysis*; D059392:Petroleum Pollution; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry
chemical_list: D006586:Hexanes; D010578:Petroleum; D012987:Soil; D012989:Soil Pollutants; C026385:n-hexane
keywords: Penalized spline; Petroleum; Random forest; Standard normal variate; Visible near infrared diffuse reflectance spectroscopy; n-hexane