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An extraction and determination method is shown for the analysis of dyes and solvents present in two types of ballpoint pen inks that are deposited onto paper. Ink extracts are analysed using a combination of gas chromatography with mass spectrometry (GC-MS), and high-pressure liquid chromatography with photodiode array detection (HPLC-DAD), within a single sample extraction procedure. Seventeen solvents and thirteen dyes contained in two Montblanc ® inks (black and blue) were monitored for 45 months at monthly intervals, in order to determine variations in the concentrations of the compounds over time. We also studied the relative variations between different compounds and the generation of degradation products such as phenol. The concentration data obtained from these compounds during their exposure have been analysed and a multiple regression model is developed for each ink type that allows an estimate of the exposure time of the ink on paper with a maximum error of between 4 and 7 months., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A sensitive, rapid and efficient ionic liquid-based vortex assisted liquid-liquid microextraction (IL-VALLME) with Liquid Chromatography Mass spectrometry (LC-MS/MS) method is proposed for the determination of bisphenols in thermal paper. Extraction factors were systematically optimized by response surface methodology. Experimental factors showing significant effects on the analytical responses were evaluated using design of experiment. The limit of detection for Bisphenol-A (BPA) and Bisphenol-S (BPS) in thermal paper were 1.25 and 0.93μgkg -1 respectively. The dynamic linearity range for BPA was between 4 and 100μgkg -1 and the determination of coefficient (R 2 ) was 0.996. The values of the same parameters were 3-100μgkg -1 and 0.998 for BPS. The extraction recoveries of BPA and BPS in thermal paper were 101% and 99%. Percent relative standard deviation (% RSD) for matrix effect and matrix match effects were not more than 10%, for both bisphenols. The proposed method uses a statistical approach for the analysis of bisphenols in environmental samples, and is easy, rapid, requires minimum organic solvents and efficient., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Mineral oil hydrocarbons are complex as well as varying mixtures and produce correspondingly complex chromatograms (on-line HPLC-GC-FID as described in Part 1): mostly humps of unresolved components are obtained, sometimes with sharp peaks on top. Chromatograms may also contain peaks of hydrocarbons from other sources which need to be subtracted from the mineral oil components. The review focuses on the interpretation and integration of chromatograms related to food contamination by mineral oil from paperboard boxes (off-set printing inks and recycled fibers), if possible distinguishing between various sources of mineral oil. Typical chromatograms are shown for relevant components and interferences as well as food samples encountered on the market. Details are pointed out which may provide relevant information. Integration is shown for examples of paperboard packaging materials as well as various foods. Finally the uncertainty of the analysis and limit of quantitation are discussed for specific examples. They primarily result from the interpretation of the chromatogram, manually placing the baseline and cuts for taking off extraneous components. Without previous enrichment, the limit of quantitation is between around 0.1 mg/kg for foods with a low fat content and 2.5 mg/kg for fats and oils. The measurement uncertainty can be kept clearly below 20% for most samples., (Copyright © 2012 Elsevier B.V. All rights reserved.)

An innovative green column-switching high-performance liquid chromatographic (HPLC) technique was developed by coupling traditional and Pb(2+) ion-exclusion columns to study enzyme hydrolysis components of waste cellulosic biomass. Pure water was used as the mobile phase to separate neutral polar analytes in high salt content solution. The column-switching HPLC-RI was connected on-line to the immobilized enzyme reactor for successive on-line desalting and simultaneous analysis of six carbohydrates (cellobiose, glucose, xylose, galactose, mannose, and arabinose) in the hydrolysate of waste paper and waste tree branch by incorporating the heart-cut and the elution-time-difference techniques. Six internal standard calibration curves in the linear concentration range of 0-2,000 microg mL(-1) were prepared. Xylitol was used as the internal standard to give excellent linear correlation coefficients (0.9984-0.9999). The limits of detection and quantification for cellobiose, glucose, xylose, galactose, mannose, and arabinose varied between 0.12-4.88 and 0.40-16.3 microg mL(-1), respectively, with an accuracy of 90-102% and a precision of 0.1-7.8%. Cellulose and hemicellulose contents were higher in waste paper than in waste tree branch., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

The determination of perfluorooctanoate (PFO) in articles of commerce has become increasingly important to understand if treated products are a possible source of PFO. An LC-MS/MS method for the determination of PFO in paper and textile using a dual labeled 13C-PFOA internal standard was successfully developed and validated. Residues of PFO were determined using an isocratic, reversed-phase high-performance liquid chromatography (HPLC) method with an ammonium acetate/methanol buffer. Ions monitored were 413 (parent) and 369 (daughter) for PFO and 415 (parent) and 370 (daughter) for dual labeled 13C-PFOA internal standard. As a precaution against ubiquitous PFO that occasionally occurs in mobile phase or instrument components, two Hypercarb cartridges (4 mm) were placed before the HPLC injector. Any PFO that was captured by the cartridges was removed before each injection by flushing the system with 100% methanol prior to equilibration with the isocratic mobile phase. Overall recovery and standard deviation over a 3 day validation regimen for samples (n=54-55) fortified with PFOA at 5, 50, and 200 ng g(-1) were 114+/-4.9% for textile and 110+/-7.6% for paper. The results also established a limit of detection (LOD) of 1 ng g(-1) in textile and 2 ng g(-1) in paper based upon S/N of the 5.0 ng g(-1) fortification versus the untreated paper and textile.

A comprehensive method for the determination of four stilbene-type disulfonate and one distyrylbiphenyl-type fluorescent whitening agents (FWAs) in paper materials (napkin and paper tissue) and infant clothes was developed. FWAs were extracted from paper material and cloth samples using a hot-water extraction, and the aqueous extracts were then preconcentrated with the newly developed Oasis WAX (mixed-mode of weak anion exchange and reversed-phase sorbent) solid-phase extraction cartridge. The analytes were unequivocal determined by ion pair chromatography coupled with negative electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS-MS), applying a di-n-hexyl-ammonium acetate (DHAA) as the ion-pairing reagent in mobile phase. Limits of quantitation (LOQ) were established between 0.2 and 0.9 ng/g in 2 g of samples. Recovery of five FWAs in spiked commercial samples was between 42 and 95% and RSD (n = 3) ranging from 2 to 11%. The method was finally applied to commercial samples, showing that two stilbene-type disulfonates were predominant FWAs detected in napkin and infant cloth samples.