MALDI‐FT‐ICR‐MS for archaeological lipid residue analysis

Soft‐ionization methods are currently at the forefront of developing novel methods for analysing degraded archaeological organic residues. Here, we present little‐used soft ionization method of matrix assisted laser desorption/ionization‐Fourier transform‐ion cyclotron resonance‐mass spectrometry (MALDI‐FT‐ICR‐MS) for the identification of archaeological lipid residues. It is a high‐resolution and sensitive method with low limits of detection capable of identifying lipid compounds in small concentrations, thus providing a highly potential new technique for the analysis of degraded lipid components. A thorough methodology development for analysing cooked and degraded food remains from ceramic vessels was carried out, and the most efficient sample preparation protocol is described. The identified components, also controlled by independent parallel analysis by gas chromatography‐mass spectrometry (GC‐MS) and gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS), demonstrate its capability of identifying very different food residues including dairy, adipose fats as well as lipids of aquatic origin. The results obtained from experimentally cooked and original archaeological samples prove the suitability of MALDI‐FT‐ICR‐MS for analysing archaeological organic residues. Sample preparation protocol and identification of compounds provide future reference for analysing various aged and degraded lipid residues in different organic and mineral matrices.     

Analysis of cancer cell lipids using matrix‐assisted laser desorption/ionization 15‐T Fourier transform ion cyclotron resonance mass spectrometry

A combination of methodologies using the extremely high mass accuracy and resolution of 15‐T Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometry (MS) was introduced for the identification of intact cancer cell phospholipids. Lipids from a malignant glioma cell line were initially analyzed at a resolution of >200 000 and identified by setting the mass tolerance to ±1 mDa using matrix‐assisted laser desorption/ionization (MALDI) 15‐T FT‐ICR MS in positive ion mode. In most cases, a database search of potential lipid candidates using the exact masses of the lipids yielded only one possible chemical composition. Extremely high mass accuracy (<0.1 ppm) was then attained by using previously identified lipids as internal standards. This, combined with an extremely high resolution (>800 000), yielded well‐resolved isotopic fine structures allowing for the identification of lipids by MALDI 15‐T FT‐ICR MS without using tandem mass spectrometric (MS/MS) analysis. Using this method, a total of 38 unique lipids were successfully identified. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis of dammar resin with MALDI‐FT‐ICR‐MS and APCI‐FT‐ICR‐MS

Comprehensive analysis of high‐resolution mass spectra of aged natural dammar resin obtained with Fourier transform ion cyclotron resonance mass spectrometer (FT‐ICR‐MS) using matrix‐assisted laser desorption/ionization (MALDI) and atmospheric pressure chemical ionization (APCI) is presented. Dammar resin is one of the most important components of painting varnishes. Dammar resin is a terpenoid resin (dominated by triterpenoids) with intrinsically very complex composition. This complexity further increases with aging. Ten different solvents and two‐component solvent mixtures were tested for sample preparation. The most suitable solvent mixtures for the MALDI‐FT‐ICR‐MS analysis were dichloromethane‐acetone and dichloromethane‐ethanol. The obtained MALDI‐FTMS mass spectrum contains nine clusters of peaks in the m/z range of 420–2200, and the obtained APCI‐FTMS mass spectrum contains three clusters of peaks in the m/z range of 380–910. The peaks in the clusters correspond to the oxygenated derivatives of terpenoids differing by the number of C₁₅H₂₄ units. The clusters, in turn, are composed of subclusters differing by the number of oxygen atoms in the molecules. Thorough analysis and identification of the components (or groups of components) by their accurate m/z ratios was carried out, and molecular formulas (elemental compositions) of all major peaks in the MALDI‐FTMS and APCI‐FTMS spectra were identified (and groups of possible isomeric compounds were proposed). In the MALDI‐FTMS and APCI‐FTMS mass spectrum, besides the oxidized C₃₀, triterpenoids also peaks corresponding to C₂₉ and C₃₁ derivatives of triterpenoids (demethylated and methylated, correspondingly) were detected. MALDI and APCI are complementary ionization sources for the analysis of natural dammar resin. In the MALDI source, preferably polar (extensively oxidized) components of the resin are ionized (mostly as Na⁺ adducts), whereas in the APCI source, preferably nonpolar (hydrocarbon and slightly oxidized) compounds are ionized (by protonation). Either of the two ionization methods, when used alone, gives an incomplete picture of the dammar resin composition. Copyright © 2012 John Wiley & Sons, Ltd.     

Molecular level comparison of water extractives of maple and oak with negative and positive ion ESI FT‐ICR mass spectrometry

Soluble extractives in wood function to protect living trees from destructive agents and also contribute to wood color and fragrance. Some extractive components have biological activities with medical applications. They also play important roles in wood processing and related applications. To increase the knowledge of wood chemistry, maple and oak were extracted by water. Ultraviolet/visible (UV/vis) spectroscopy indicated the presence of a phenolic compound, resorcinol, in maple extractives having higher molecular mass and more aromatic components than oak extractives. Negative and positive electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT‐ICR‐MS) identified thousands of formulas in the two samples in the m/z range of 200 to 800. They mainly fall into the lignin‐like, carbohydrate‐like, and tannin‐like compound categories. The top 25 peaks (ie, formulas) with the highest relative magnitude in negative ESI represented nearly 50% of the summed total spectral magnitude of all formulas assigned in the maple and oak extractives. Furthermore, the base peak (ie, most abundant peak) accounted for about 14% of the total abundance in each wood sample. Literature comparisons identified 17 of 20 formulas in the top five peaks of the four spectra as specific bioactive compounds in trees and other plants, implying the potential to explore utilization of maple and oak extractives for functional and medicinal applications. The various profiling of the top 25 peaks from the two samples also suggested the possible application of FT‐ICR‐MS for detecting chemical markers useful in profiling and identification of wood types and sources.     

Investigating sorption-driven dissolved organic matter fractionation by multidimensional fluorescence spectroscopy and PARAFAC

Soil organic matter is involved in many ecosystem processes, such as nutrient supply, metal solubilization, and carbon sequestration. This study examined the ability of multidimensional fluorescence spectroscopy and parallel factor analysis (PARAFAC) to provide detailed chemical information on the preferential sorption of higher-molecular-weight components of natural organic matter onto mineral surfaces. Dissolved organic matter (DOM) from soil organic horizons and tree leaf tissues was obtained using water extracts. The suite of fluorescence spectra was modeled with PARAFAC and it was revealed that the DOM extracts contained five fluorescing components: tryptophan-like (peak location at excitation <255 nm:emission 342 nm), tyrosine-like (276 nm:312 nm), and three humic-substance-like components (<255 nm:456 nm, 309 nm:426 nm, <255 nm:401 nm). In general, adsorption onto goethite and gibbsite increased with increasing DOM molecular weight and humification. PARAFAC analysis of the pre- and post-sorption DOM indicated that the ordering of sorption extent was humic-like components (average 91% sorption) > tryptophan-like components (52% sorption) > tyrosine-like components (29% sorption). This differential sorption of the modeled DOM components in both the soil organic horizon and leaf tissue extracts led to the fractionation of DOM. The results of this study demonstrate that multidimensional fluorescence spectroscopy combined with PARAFAC can quantitatively describe the chemical fractionation process due to the interaction of DOM with mineral surfaces.     

Effect of Pyrolysis Temperature on the Characterisation of Dissolved Organic Matter from Pyroligneous Acid

Dissolved organic matter (DOM) greatly influences the transformation of nutrients and pollutants in the environment. To investigate the effects of pyrolysis temperatures on the composition and evolution of pyroligneous acid (PA)-derived DOM, DOM solutions extracted from a series of PA derived from eucalyptus at five pyrolysis temperature ranges (240–420 °C) were analysed with Fourier transform infrared spectroscopy, gas chromatography–mass spectroscopy, and fluorescence spectroscopy. Results showed that the dissolved organic carbon content sharply increased (p < 0.05) with an increase in pyrolysis temperature. Analysis of the dissolved organic matter composition showed that humic-acid-like substances (71.34–100%) dominated and other fluorescent components (i.e., fulvic-acid-like, soluble microbial by-products, and proteinlike substances) disappeared at high temperatures (>370 °C). The results of two-dimensional correlation spectroscopic analysis suggested that with increasing pyrolysis temperatures, the humic-acid-like substances became more sensitive than other fluorescent components. This study provides valuable information on the characteristic evolution of PA-derived DOM.     

Aquatic plant‐derived changes in oil sands naphthenic acid signatures determined by low‐, high‐ and ultrahigh‐resolution mass spectrometry

Mass spectrometry is a common tool for studying the fate of complex organic compound mixtures in oil sands processed water (OSPW), but a comparison of low‐, high‐ (～10 000), and ultrahigh‐resolution (～400 000) instrumentation for this purpose has not previously been made. High‐resolution quadrupole time‐of‐flight mass spectrometry (QTOF MS) and ultrahigh‐resolution Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS), with negative‐ion electrospray ionization, provided evidence for the selective dissipation of components in OSPW. Dissipation of oil sands naphthenic acids (NAs with general formula C_nH_2n+zO₂ where n is the number of carbon atoms, and Z is zero or a negative even number describing the number of rings) was masked (by components such as fatty acids, O₃, O₅, O₆, O₇, SO₂, SO₃, SO₄, SO₅, SO₆, and NO₄ species) at low resolution (1000) when using a triple quadrupole mass spectrometer. Changes observed in the relative composition of components in OSPW appear to be due primarily to the presence of plants, specifically cattails (Typha latifolia) and their associated microorganisms. The observed dissipation included a range of heteratomic species containing O₂, O₃, O₄, and O₅, present in Athabasca oil sands acid extracts. For the heteratomic O₂ species, namely naphthenic acids, an interesting structural relationship suggests that low and high carbon number NAs are dissipated by the plants preferentially, with a minimum around C₁₄/C₁₅. Other heteratomic species containing O₆, O₇, SO₂, SO₃, SO₄, SO₅, SO₆, and NO₄ appear to be relatively recalcitrant to the cattails and were not dissipated to the same extent in planted systems. Copyright © 2009 John Wiley & Sons, Ltd.     

Evidence for electron‐based ion generation in radio‐frequency ionization

Radio‐frequency ionization (RFI) is a novel ionization method coupled to mass spectrometry (MS) for analysis of semi‐volatile and volatile organic compounds (VOCs). Despite the demonstrated capabilities of RFI MS for VOC analysis in both positive‐ and negative‐ion modes, mechanism of RFI is not completely understood. Improved understanding of the ion generation process in RFI should expand its utility in MS. Here, we studied the possibility of electron emission in RFI using both direct charged particle current measurements and indirect electron detection in a 9.4‐T Fourier transform‐ion cyclotron resonance (FT‐ICR) mass spectrometer. We show that RF‐generated electrons can be trapped in the ICR cell and, subsequently, reacted with neutral hexafluorobenzene (C₆F₆) molecules to generate C₆F₆^●?. Intensity of observed C₆F₆^●? species correlated with the number of trapped electrons and decreased as a function of electron quenching period. We also measured the electron attachment rate constant of hexafluorobenzene using a post‐RF electron trapping experiment. Measured electron attachment rate constant of hexafluorobenzene (1.19 (±0.53) × 10^?9 cm³ molecule^?1 s^?1) for post‐RF FT‐ICR MS agreed with the previously reported value (1.60 (±0.30) × 10^?9 cm³ molecule^?1 s^?1) from low‐pressure ICR MS measurements. Experimental results from direct and indirect electron measurements suggest that RFI process involves RF‐generated electrons under ultrahigh vacuum conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

Influence of acidification on the optical properties and molecular composition of dissolved organic matter

Acidification is a common method for preserving dissolved organic matter (DOM) in natural water samples until sophisticated laboratory analyses can be performed. However, little is known about the effects of this practice on the composition and optical properties of DOM. In this study, the effects of acidification on DOM in porewater samples collected from the RL IV bog system of the Glacial Lake Agassiz Peatlands in northern Minnesota were characterized. Molecular composition was determined by ultrahigh resolution mass spectrometry and optical properties by UV absorption and three-dimensional fluorescence spectroscopy. Excitation–emission matrix fluorescence spectroscopy results indicate that the fluorescence properties of the peatland porewater DOM were sensitive to pH and that the observed changes were fluorophore dependent. Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry revealed the appearance of newly formed, oxygen-rich compounds upon acidification. The extent to which these oxygen-rich compounds were formed was also dependent on the composition of the DOM.     

Estuarine water classification using EEM spectroscopy and PARAFAC-SIMCA

The primary method for the prevention of the introduction of nonindigenous aquatic nuisance species in the U.S. is ballast water exchange (BWE). Our recent work focused on the use of the excitation emission matrix (EEM) spectroscopy of the colored dissolved organic matter (CDOM) to “fingerprint” water as a function of its port of origin, and therefore provide a forensic tool for the enforcement of BWE regulations. In that work, we utilized N-way partial least squares with discriminant analysis (NPLS-DA), which models the data with an emphasis on differences among classes (ports of origin). In this work, EEMs of samples from three different U.S. ports were analyzed by parallel factor analysis (PARAFAC) coupled with soft independent modeling of class analogy (SIMCA) to provide an effective classification method with a low false positive rate. This coupling, which is shown for the first time in this work, can be a useful alternative to NPLS-DA in that PARAFAC-SIMCA decomposes the EEM signal into chemical components and utilizes the scores for these components in the classification scheme. This gives the user the option of removing the contributions of interfering or unidentifiable fluorescent components prior to classification.     

Characterization of chemical constituents in Rhodiola Crenulate by high‐performance liquid chromatography coupled with Fourier‐transform ion cyclotron resonance mass spectrometer (HPLC‐FT‐ICR MS)

In this work, an approach using high‐performance liquid chromatography coupled with diode‐array detection and Fourier‐transform ion cyclotron resonance mass spectrometer (HPLC‐FT‐ICR MS) for the identification and profiling of chemical constituents in Rhodiola crenulata was developed for the first time. The chromatographic separation was achieved on an Inertsil ODS‐3 column (150 mm × 4.6 mm,3 µm) using a gradient elution program, and the detection was performed on a Bruker Solarix 7.0 T mass spectrometer equipped with electrospray ionization source in both positive and negative modes. Under the optimized conditions, a total of 48 chemical compounds, including 26 alcohols and their glycosides, 12 flavonoids and their glycosides, 5 flavanols and gallic acid derivatives, 4 organic acids and 1 cyanogenic glycoside were identified or tentatively characterized. The results indicated that the developed HPLC‐FT‐ICR MS method with ultra‐high sensitivity and resolution is suitable for identifying and characterizing the chemical constituents in R. crenulata. And it provides a helpful chemical basis for further research on R. crenulata. Copyright © 2016 John Wiley & Sons, Ltd.     

Method development for the analysis of resinous materials with MALDI‐FT‐ICR‐MS: novel internal standards and a new matrix material for negative ion mode

Matrix‐assisted laser desorption/ionization (MALDI) is a mass spectrometry (MS) ionization technique suitable for a wide variety of sample types including highly complex ones such as natural resinous materials. Coupled with Fourier transform ion cyclotron resonance (FT‐ICR) mass analyser, which provides mass spectra with high resolution and accuracy, the method gives a wealth of information about the composition of the sample. One of the key aspects in MALDI‐MS is the right choice of matrix compound. We have previously demonstrated that 2,5‐dihydroxybenzoic acid is suitable for the positive ion mode analysis of resinous samples. However, 2,5‐dihydroxybenzoic acid was found to be unsuitable for the analysis of these samples in the negative ion mode. The second problem addressed was the limited choice of calibration standards offering a flexible selection of m/z values under m/z 1000. This study presents a modified MALDI‐FT‐ICR‐MS method for the analysis of resinous materials, which incorporates a novel matrix compound, 2‐aminoacridine for the negative ion mode analysis and extends the selection of internal standards with m/z <1000 for both positive (15 different phosphazenium cations) and negative (anions of four fluorine‐rich sulpho‐compounds) ion mode. The novel internal calibration compounds and matrix material were tested for the analysis of various natural resins and real‐life varnish samples taken from cultural heritage objects. Copyright © 2017 John Wiley & Sons, Ltd.     

Determination of Riboflavin in Human Plasma by Excitation‐Emission Matrix Fluorescence and Multi‐Way Analysis

Direct determination of riboflavin (Fig. 1), a vitamin, in human plasma was accomplished based on excitation‐emission matrix (EEM) fluorescence measurements and multi‐way chemometrics method based on parallel factor analysis (PARAFAC). The PARAFAC trilinear model, without restrictions and using one factor was used in the data analysis. The excitation wavelength range was from 380 to 460 nm and the emission was recorded from 480 to 600 nm. The calibration set was constructed with sixteen standard solutions in a concentration range of 0.02–0.38 μg mL^?1 for riboflavin. The capabilities of the method for the analysis were evaluated by determination of riboflavin in synthetic and real samples with satisfactory results. The accuracy of the methods, evaluated through the root mean square error of prediction (RMSEP), was 0.0059 for riboflavin by the PARAFAC model. Also, partial least squares (PLS) model was built at one excitation wavelength and used to determine a set of synthetic and real samples. The best model was obtained with PARAFAC. This result shows that molecular fluorescence spectroscopy can be used for the development of robust analytical methods for the direct determination of riboflavin in complex backgrounds such as human plasma.     

Non‐disturbing characterization of natural organic matter (NOM) contained in clay rock pore water by mass spectrometry using electrospray and atmospheric pressure chemical ionization modes

We have investigated the composition of the mobile natural organic matter (NOM) present in Callovo‐Oxfodian pore water using electrospray ionization mass spectrometry (ESI‐MS), atmospheric pressure chemical ionization mass spectrometry (APCI‐MS) and emission‐excitation matrix (EEM) spectroscopy. The generation of knowledge of the composition, structure and size of mobile NOM is necessary if one wants to understand the interactions of these compounds with heavy metals/radionuclides, in the context of environmental studies, and particularly how the mobility of these trace elements is affected by mobile NOM. The proposed methodology is very sensitive in unambiguously identifying the in situ composition of dissolved NOM in water even at very low NOM concentration, due to innovative non‐disturbing water sampling and ionization (ESI/APCI‐MS) techniques. It was possible to analyze a quite exhaustive inventory of the small organic compounds of clay pore water without proceeding to any chemical treatment at naturally occurring concentration levels. The structural features observed were mainly acidic compounds and fatty acids as well as aldehydes and amino acids. Copyright © 2009 John Wiley & Sons, Ltd.     

Combination of Solid‐Phase Micro‐Extraction and Direct Analysis in Real Time‐Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for Sensitive and Rapid Analysis of 15 Phthalate Plasticizers in Beverages

A method for rapid identification and quantification of phthalate plasticizers in beverages was developed. A number of 15 phthalate plasticizers which covered all the phthalates concerned in the US Consumer Product Safety Improvement Act (CPSIA), European Union legislations and Chinese national standards (GB) were analyzed. By a combined solid‐phase micro‐extraction (SPME) and direct analysis in real time mass spectrometry (DART‐MS) approach, phthalates at sub‐ng·mL^?1 levels can be qualitatively and quantitatively analyzed in a short time. The use of ultrahigh‐resolving power and the accurate mass measurement capacity naturally provided by Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR‐MS) minimizes the matrix interferences and thus enables the evaluation of phthalates in a complex matrix without extensive sample handlings or preparations. The limits of quantification (LOQs) were estimated to be at 0.3–5.0 ng·mL^?1, lower than the Maximum Residue Limit (MRL) regulated by the European Union legislations (2007/19/EC) in foods, beverages, food packaging and toys (0.3–30 ng·mL^?1). This rapid and easy‐to‐use SPME‐DART‐FT‐ICR‐MS method provided a relatively high‐throughput and powerful analytical approach for quick testing and screening phthalates in beverages and water samples to ensure food safety.     

Normal‐phase high‐performance counter‐current chromatography for the fractionation of dissolved organic matter from a freshwater source

Normal‐phase high‐performance counter‐current chromatography (HPCCC) is used to obtain a preliminary fractionation of components in dissolved organic matter (DOM) from a freshwater source. The HPCCC solvent system involved a normal‐phase approach with water/methanol (1:1) as the lower stationary phase and hexane/ethyl acetate (1:1) as the upper mobile phase. The critical experiment parameters were optimised: revolution speed 1800 rpm and flow rate 0.15 mL/min. Under these conditions 50 μL of a 0.50 mg/mL DOM solution was loaded. The detection wavelength was monitored at 330 nm in order to isolate the main portion of DOM, which includes substances such as carboxyl‐rich alicyclic molecules. By optimising this system it was possible to isolate materials that, according to GC–MS, can be related to molecules with an analogous structural background. Where fraction analysis was not suitable for GC–MS, RP‐HPLC with UV absorbance detection was used, showing unique chromatograms for each fraction at both 210 and 330 nm.     

Exploring the chemical profile of designer drugs by ESI(+) and PSI(+) mass spectrometry—An approach on the fragmentation mechanisms and chemometric analysis

The consumption of design drugs, frequently known as new psychoactive substances (NPS), has increased considerably worldwide, becoming a severe issue for the responsible governmental agencies. These illicit substances can be defined as synthetic compounds produced in clandestine laboratories in order to act as analogs of schedule drugs mimetizing its chemical structure and improving its pharmacological effects while hampering the control and making regulation more complicated. In this way, the development of new methodologies for chemical analysis of NPS drugs is indispensable to determine a novel class of drugs arising from the underground market. Therefore, this work shows the use of high‐resolution mass spectrometry Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) applying different ionization sources such as paper spray ionization (PSI) and electrospray ionization (ESI) in the evaluation of miscellaneous of seized drugs samples as blotter paper (n = 79) and tablet (n = 100). Also, an elucidative analysis was performed by ESI(+)MS/MS experiments, and fragmentation mechanisms were proposed to confirm the chemical structure of compounds identified. Besides, the results of ESI(+) and PSI(+)‐FT‐ICR MS were compared with those of GC–MS, revealing that ESI(+)MS showed greater detection efficiency among the methodologies employed in this study. Moreover, this study stands out as a guide for the chemical analysis of NPS drugs, highlighting the differences between the techniques of ESI(+)‐FT‐ICR MS, PSI(+)‐FT‐ICR MS, and GC–MS.     

A fully robust PARAFAC method for analyzing fluorescence data

Parallel factor analysis (PARAFAC) is a widespread method for modeling fluorescence data by means of an alternating least squares procedure. Consequently, the PARAFAC estimates are highly influenced by outlying excitation–emission landscapes (EEM) and element‐wise outliers, like for example Raman and Rayleigh scatter. Recently, a robust PARAFAC method that circumvents the harmful effects of outlying samples has been developed. For removing the scatter effects on the final PARAFAC model, different techniques exist. Newly, an automated scatter identification tool has been constructed. However, there still exists no robust method for handling fluorescence data encountering both outlying EEM landscapes and scatter. In this paper, we present an iterative algorithm where the robust PARAFAC method and the scatter identification tool are alternately performed. A fully automated robust PARAFAC method is obtained in that way. The method is assessed by means of simulations and a laboratory‐made data set. Copyright © 2009 John Wiley & Sons, Ltd.     

Three‐way analysis of a designed compost experiment using near‐infrared spectroscopy and laboratory measurements

Composts are complex organic systems that undergo batch fermentation processes. Traditional monitoring of such processes is usually based on measuring important chemical (physical) laboratory parameters but the common trend includes using more rapid and non‐destructive methods like near‐infrared (NIR) spectroscopy. A lab‐scale designed (simplex mixture) experiment with nine compost batches, including three repeated centre point batches, was monitored over 5 weeks by NIR spectroscopy (900–1700 nm) and by wet chemical and physical measurements: pH, energy content, moisture content, NH₃/NH and temperature. The data were organized in three‐way data arrays and different three‐way methods were used for analysis: (1) PARAFAC, (2) Tucker3 and (3) PARAFAC2. The present paper stresses the advantages and the possibilities of three‐way methods compared to traditional two‐way analysis methods such as principal component analysis (PCA). Two‐way methods have a tendency to mix variables and produce, from a parsimony point of view, more complex models which are hard to interpret. The results from the three‐way methods reproduced the mixture triangle, gave common time profiles (PARAFAC and Tucker3) for all compost batches and rate constants (half‐lives) could be calculated: 6.9 days for the PARAFAC loadings from the chemical/physical parameters and between 6 and 10 days for the PARAFAC loadings from the NIR data. PARAFAC2 includes the possibility of getting individual time profiles for each compost batch. The results show that chemical/physical data and the NIR data give similar interpretations. The conclusion is that three‐way methods can be used to monitor composts batches over time. Copyright © 2011 John Wiley & Sons, Ltd.