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Fluoro-functionalized paper was prepared and applied in solid phase extraction (SPE) for the analysis of trace-level perfluorinated compounds (PFCs). The proposed fluoro-functionalized paper-based solid-phase extraction (Fp-SPE) exhibits significant advantages for sample preparation, such as the biodegradability of paper-based adsorbent, simple manipulation and low cost. Owing to the fluorous affinity, the Fp-SPE technique with high sensitivity and high selectivity is more suitable for the selective enrichment of fluorine-containing molecules from the background of non-fluorinated organic compounds in a real water sample. Combined with high-performance liquid chromatography coupled with electrospray ionization-tandem mass spectrometry analysis (HPLC-MS/MS), the linear range of the PFCs, including perfluorobutyric acid (PFBA), perfluorooctanic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorodecanoic acid (PFDA), was 0.20–5.0 ng/L with the limits of detection (LOD) ranging from 0.04–0.05 ng/L and the limits of quantification (LOQ) ranging from 0.15-0.20 ng/L. The method was then applied to the analysis of tap water, river water and waste water samples. The results of the actual sample analysis are consistent with that by reverse phase SPE (RP-SPE).

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 (R2) 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.

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.

High-performance affinity chromatography is limited by its high cost and high pressure. Paper is made up of porous fiber networks and has the properties of low cost, ease of fabrication, and biodegradable. Due to these advantages, herein, we immobilized beta2-adrenoceptor (β2-AR) onto the surface of the polytetrafluoroethylene membrane, a paper-based material, and constructed a G protein-coupled receptor (GPCR)-in-paper chromatographic platform. This platform was characterized by Fourier transform infrared spectroscopy, fluorescence analysis, X-ray photoelectron spectroscopy, and chromatographic studies. These morphological and elemental analysis showed that β2-AR was successfully immobilized on the paper surface. The specific drugs have good retentions on the GPCR-in-paper chromatographic platform. The association constants of salbutamol, terbutaline and bambuterol to β2-AR were calculated to be 2.02 × 104 M−1, 1.15 × 104 M−1, 1.75 × 104 M−1 by adsorption energy distribution, which were in good line with the values from frontal analysis, zonal elution and previous literatures. We demonstrated that the GPCR-in-paper platform was cost-effective, easy to be modified for protein immobilization, and applicable in the receptor-drug interaction analysis. We believe such a platform sheds new light on paper chromatography for receptor-drug interaction analysis and other applications.

Herein, we report three-dimensional paper chromatography (3D-PC) as a micro-chromatographic platform. The method was based on applying the origami microfluidic device for separation, coupled by colorimetric methods for simultaneous determination. The microfluidic device fabrication was a facile printing approach. Two azo food dyes, Tartrazine (E102) and Indigo carmine (E132), were selected as a model analyte, while carbonate-bicarbonate buffer was used as the mobile phase. Our micro-chromatographic device is associated with two big advantages including needing very small volume of mobile phase ( ~12 µL) and ultrafast separation time (~35 s). Under the optimal conditions, the method provided acceptable linear ranges of 0. 0 g L 1–18.0 g L 1 (R2 = 0.997) for E102 and 0.070 g L 1–10.0 g L 1 for E132 and the limits of detection (3σ/slope) were evaluated as 0.620 and 0.060 g L 1, respectively. The proposed method was successfully applied in the separation and quantification of these dyes in commercial food products such as jelly, candy, and four kinds of drink samples without any sample preparation prior to analysis. The mean recovery values for the real sample analysis were in the range of 100.14%–102.38% for E132 and E102 respectively. The inter-device relative standard deviations were in the ranges of 1.5%–11.8%. In total, our chromatographic μPAD is small (1.0 cm × 1.0 cm × 0.5 cm), portable, inexpensive, no need of specialized user, requires low volumes of sample (0.5 μL), and can perform separation using 12 μL of aqueous mobile phase in very short time.

Paper-based sorptive phases (PSPs) are functional planar materials with a demonstrated potential in analytical sample preparation. This article describes the synthesis of a polyimide coated paper by an in-situ imidization at a high temperature. Polyimides (PI) are synthesized in two subsequent steps where a hydrophilic polymer, in this case, poly(amic acid) (PAA), is formed as an intermediate product. PAA is finally transformed into hydrophobic PI by thermal curing at 180 °C. The synthesis of PI-paper takes advantage of this two-step procedure. In the first stage, a segment of filter paper is immersed into an aqueous PAA solution. After the solvent evaporation, the paper is heated at 180 °C for 1 h inducing the formation of the hydrophobic PI over the cellulose fibers. Infrared spectroscopy has been used to characterize the synthesized materials by defining a coverage factor F. The hydrophobicity of the materials has been studied using an aqueous methylene blue solution as a marker. To fully demonstrate the usefulness of the material in the sample preparation field, the extraction of methadone from oral fluid (OF) samples has been considered as a model analytical problem. The main variables affecting the synthesis (PAA concentration on the precursor solution and number of dips) and the extraction (elution and extraction times) have been fully evaluated. Working under the optimum conditions, a limit of quantification of 9 µg/L, intraday and interday precision better than 14.6%, and accuracy in the range of 87-108% were obtained.

This manuscript describes the development of a capillary electrophoresis (CE) method for the detection of acid and basic dyes and its application to real samples, blue-pen-ink strokes on office paper. First, a capillary zone electrophoresis (CZE) method was developed for the separation of basic and acid dyes, by studying the separation medium (buffer nature, pH and relative amount of additive) and instrumental parameters (temperature, voltage and capillary dimensions). The method performance was evaluated in terms of selectivity, resolution (above 5 and 2 for acid dyes and basic dyes, respectively, except for two basic dye standards), LOD (lower than 0.4 mg/L) and precision as intraday and interday RSD values of peak migration times (lower than 0.6%). The developed method was then applied to 34 blue pens from different technologies (rollerball, ballpoint, markers) and with different ink composition (gel, water-based, oil-based). A microdestructive sample treatment using a scalpel to scratch 0.3 mg of ink stroke was performed. The entire electropherogram profile allowed the visual discrimination between different types of ink and brands, being not necessary a statistical treatment. A 100% of discrimination was achieved between pen technologies, brands, and models, although non-reproducible zones in the electropherograms were found for blue gel pen samples. The two different batches of blue oil-based pens were also differentiated. Thus, this method provides a simple, microdestructive, and rapid analysis of different blue pen technologies which may complement the current analysis of questioned documents performed by forensic laboratories.

This study reports on a rapid method for the determination of methanol in paper-based materials by alkaline extraction, coupled with headspace analysis. Methanol partition equilibria between solid–liquid phases and vapor–liquid phases were conducted in two separate containers, from which an equation for calculating the total methanol content in the original paper sample was derived. It was found that the extraction equilibrium of methanol from solid sample could be achieved within 5 min at room temperature using a high-speed disintegrator, and a subsequent neutralization step is an effective way to prevent methanol from being regenerated at high temperature during headspace equilibration. The results showed that the relative standard deviations for reproducibility tests were in the range of 1.86–6.03%, and the recoveries were in the range of 92.3–107%. The present method is simple and practical; it can be an efficient tool for quantifying the methanol content in paper-based materials and thus play an important role in the investigation of methanol migration behavior in food and beverage packaging.

In this paper, chemically modified cellulose paper was introduced as a novel extracting phase for thin film microextraction (TFME). Different reagents (Octadecyltrichlorosilane, diphenyldichlorosilane, cyclohexyl isocyanate and phenyl isocyanate) were used to modify the cellulose papers. The modified papers were evaluated as a sorbent for the extraction of some synthetic and natural estrogenic hormones (17α-ethynylestradiol, estriol and estradiol) from aqueous samples. Liquid chromatography–fluorescence detection was used for the quantification of the extracted compounds. The cellulose paper modified with phenyl isocyanate showed the best affinity to the target compounds. TEME parameters such as desorption condition, shaking rate, sample ionic strength and extraction time were investigated and optimized. Limit of detections were between 0.05 and 0.23 μg L −1 and relative standard deviations were less than 11.1% under the optimized condition. The calibration curves were obtained in the range of 0.2–100 μg L −1 with a good linearity ( r 2 > 0.9935). Wastewater, human urine, pool and river water samples were studied as real samples for the evaluation of the method. Relative recoveries were found to be between 75% and 101%.

We developed a convenient method by coupling frontal elution paper chromatography with desorption corona beam ionization mass spectrometry (DCBI-MS) for rapid determination of chlorphenamine added in herbal medicines or dietary supplements. In this method, the ethanol extract of the herbal products was spotted directly onto an isosceles triangular filter paper sheet, and then the paper sheet was developed under strong elution condition with the sample zone migrating at the solvent front. The analyte was finally condensed at the V-shaped tip which could then be placed under the visible plasma beam of DCBI for ionization. The overall procedure took less than 5 min. The frontal elution paper chromatography on a triangular plate used in this work improved the signal intensity of chlorphenamine by 30-fold due to the analyte condensing at the tip and the reduction of the background suppression. Furthermore, the paper sheet also functioned as a filter in the analysis of solid or powder samples, which can increase the analytical throughput by omitting the step of centrifugation. The proposed method in current study was successfully applied in the determination of chlorphenamine in herbal medicines. Chlorphenamine was detected in four of the twelve types of herbal medicines examined in this study. The limit of detection was 200 ng/mL (2.0 ng absolute) in full-scan positive-ion mode and the linear range was from 5.0 μg/mL to 50 μg/mL with satisfactory linear coefficient (R(2) (the square of the correlation coefficient)=0.895). Good reproducibility was achieved with relative standard deviations (RSDs) less than 15.0% and the recoveries of chlorphenamine ranged from 84.3 to 90.6%.

With the increasing demand of new drugs for the treatment of Alzheimer's disease (AD), screening acetylcholinesterase (AChE) inhibitors from traditional Chinese medicines (TCMs) has been proved to be an effective strategy for drug discovery. In present study, a novel strategy was developed to fish out AChE inhibitors from Terminalia chebula fruits based on immobilized AChE coupled with ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and molecular docking. For AChE immobilization, cellulose filter paper (CFP) as the carrier was modified with chitosan to be introduced to amino groups, and then AChE was modified on the amino-modified CFP through a Schiff base reaction with glutaraldehyde as a cross-linking agent. The CPF-immobilized AChE possessed advantages of a wider range for pH and temperature endurance, better storage stability, excellent reproducibility and reusability. The CPF-immobilized AChE was incubated with the extract of T. chebula fruits, and then the active components would form complexes with immobilized AChE. The complexes were further conveniently separated with inactive components by virtue of the instantaneous separation characteristic of CFP. Eventually, 25 (1-11, 13-26) potential AChE inhibitors were fished out and their structures were further identified by UPLC-QTOF-MS. Moreover, molecular docking was performed to discriminate non-specific compounds to AChE and explore binding mechanisms between potential inhibitors and AChE, and 25 compounds could be well embedded into active sites of AChE with affinities ranging from -9.9 to -6.4 kcal/mol. Inhibitory activities of screened active components on AChE were evaluated in vitro, and punicalagin, 1,3,6-tri-O-galloyl-β-D-glucose (1,3,6-TGG), chebulinic acid and geraniin exhibited excellent AChE-inhibitory properties with IC

The paper deals with the application of size exclusion chromatography (SEC) for the studies of paper degradation phenomena. The goal is to solve some of the technical problems connected with the calibration of multi-detector SEC system and to find the correlation between SEC and viscometric results of degree of polymerization of cellulose. The results gathered for the paper samples degraded by acidic air pollutant (NO(2)) are used as an example of SEC-MALLS application. From the correlation between intrinsic viscosities and absolute value of molecular masses obtained with SEC/MALLS (Multi Angle Laser Light Scattering) technique, Mark-Houwink coefficients for cellulose in cupri-ethylenediamine solution were determined. Thus obtained coefficients were used for the determination of viscometric degree of polymerization (molecular mass) of the aged samples. An excellent correlation was found between the chromatographic values of molecular masses obtained with SEC-UV/VIS detection and the viscometric ones utilizing the improved values of Mark-Houwink coefficients.

This paper described a convenient semiquantitative method for colorimetric detection of protein with self-calibration integrated on the test strip. Hydrophilic paper was employed as microfluidic device for running colorimetric assay, tree-shaped design was developed to ensure uniform microfluidic flow for multiple branches. The approach was validated with bovine serum albumin (BSA) colorimetric detection, and colorimetric results observed by naked eyes were consistent with that from apparatus. The device could be coupled with digital transmission of images for remote monitoring system for diagnosis, food control, and environmental analysis.

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.

When the degree of closure of the paper machine wet end waters increases, wet end problems also become more difficult to control without specific and selective on-line measurements. The need to measure the concentrations of individual compounds in order to explain wet end phenomena is growing. This study was performed to set up a CE system to a paper machine and to determine soluble inorganic and organic ions in different locations of pulp and paper process waters with real time analyses by two on-line CE methods. A reconstructed commercial CE apparatus was connected to a papermaking machine via an apparatus, which was a combined sampling and sample pretreatment instrument, the role of which was to filter and dilute the samples before on-line determination by CE. The on-line procedures were optimized for simultaneous determination of anions as chloride, sulfate, oxalate, formate and acetate and for determination of cations as potassium, calcium, sodium, magnesium and traces of aluminium. The quantification was performed with external standard methods using the programs available in the commercial CE instrument. The concentrations of the ions were transferred by using a computerized transfer algorithm exporting the results from the analysis instrument to the process control unit. The developed on-line procedures were tested three times in paper and paperboard mills for 1 month at a time. Correlations were observed between the CE results and changes in the processes.

A solid-phase microextraction (SPME) method has been developed for the determination of pentachlorophenol (PCP) in paper and board samples. The analytical procedure involves direct extraction of PCP from paper and board samples and determination by gas chromatography with electron capture detection (GC-ECD). Two kinds of commercially available fibres; 100 microm polydimethylsiloxane (PDMS), apolar, and 85 microm polyacrylate (PA), quite polar, were evaluated to determine the extraction efficiency of pentachlorophenol. Parameters affecting the extraction process, such as temperature and time, were studied. Moreover, time of desorption and the effect of addition of salt were also investigated. The optimized procedure was applied to the analysis of pentachlorophenol (PCP) in five samples of virgin and recycled paper and board. The PCP content was determined by GC-ECD. To evaluate the effectiveness of the proposed method, it was compared with conventional extraction method with liquid-liquid extraction and derivatization. Detection limit of 0.015 microg/g for PCP in paper was achieved with a RSD of 14%.

Two low-volume solvent continuous extraction methods are applied to the extraction of paper matrices. In the methods reported here, a complex mixture of fluorescent whitening agents (FWAs) and azo dyes (AZOs) used in paper materials intended to come into contact with foodstuffs was extracted by using subcritical water extraction (SWE) and dynamic sonication-assisted solvent extraction (DSASE). Rationale for the work is based upon migration concerns of these groups of analytes from the packaging to the packaged items, thus compromising their subjective and/or objective quality. In SWE, sample was extracted in 21 min with 0.5 mL of water, whereas the DSASE method required 11 min and used 7 mL of water. DSASE was further developed by incorporating an organic modifier in order to change water polarity, thus improving extraction of moderately polar analytes. This way, modified-DSASE used a total organic volume of 0.9 mL which represents a reduction of 200 times in organic solvent consumption (200 mL versus approximately 1.0 mL) and 11 times in extraction time (2 h versus 11 min) compared to the existing methods. SWE was able to extract only 9 out of 12 test analytes with average recoveries between 10 and 25% whereas modified-DSASE succeed in extracting all the target analytes with an average recovery of 89%. Complete discussion and explanation concerning these differences are provided in the text.

Paper fiber was treated in a heterogeneous esterification reaction with four different fatty acids. This fiber was used to strengthen polyethylene (PE) composites. Modified and unmodified cellulose fiber was characterized with inverse gas chromatography. In previous work, characterization was also carried with X-ray photoelectron spectroscopy (XPS), solid-state NMR, differential scanning calorimetry and thermogravimetry. Individual fibers were found to be covered with the corresponding esters (cellulose undecylenate, undecanoate, oleate, stearate) with partial degrees of substitution of the cellulose. Comparison of XPS and NMR results showed that the surface degree of substitution of the cellulose fiber was higher than for the bulk, showing that the esterification reaction was a surface phenomenon. The aim of this work was to acquire information on the surface characteristics of the fiber and to see whether it could be correlated to PE composite mechanical strength results. The conclusions are that polar probes seem to diffuse more into the fibers than the non-polar probes, as the non-polar component of the surface tension of the modified fiber is much lowered towards that of PE, while donor–acceptor characteristics are hardly changed by esterification. The ester with the lowest non-polar component of the surface energy, the oleate, also gives the composite with the best mechanical properties.

Filter paper pieces-based (FPB) DEAE-cellulose was prepared for direct fractionation of proteins in particle-containing feedstocks. FPB DEAE-cellulose has a protein binding capacity equivalent to that of commercially available DEAE-cellulose. Crude extracts from porcine intestine and kiwi fruit pulp, which were unmanageable by commercially available chromatographic media due to rapid clotting, could be directly fractionated with FPB DEAE-cellulose column. In addition, effluents from an FPB DEAE-cellulose column were extensively clarified. The present approach can be used as a rapid, robust and low-cost capturing step for protein from particle-containing feedstocks.

The surface energies of various inorganic fillers including kaolin clay, titanium dioxide, and talc were examined using inverse gas chromatography (IGC). In an earlier investigation that examined calcium carbonate fillers, dehydration by heating under a dry nitrogen purge had a substantial influence on the apolar (gammaS(LW)) and polar (gammaS(AB)) components of surface energy as measured using IGC. Using the same approach, the influence of such conditioning on several inorganic fillers used in papermaking were determined using preconditioning IGC from 100 to 300 degrees C, and sequential isothermal analysis at 100 degrees C. Results from IGC analysis of titanium dioxides (rutile and anatase) were similar to precipitated calcium carbonate (PCC) for temperatures up to 200 degrees C. PCC was significantly more energetic after preconditioning at 300 degrees C, which may indicate the onset of significant thermal decomposition that titanium dioxides will not exhibit. Kaolin clay samples had relatively high apolar surface energy similar to that of the chalk samples. Calcination gave lower gammaS(LW) values that could not be accounted for by changes in the microporous structure. More likely the differences resulted from contamination of highly energetic surface sites with adsorbates other than water. Talc samples exhibited relatively high apolar surface energies that increased with preconditioning temperature. The results provided insight into the significance of water on the final adhesion properties of fillers in the sheet structure or coating layer.

A method for the determination of nitrilotriacetic (NTA), ethylenediaminetetraacetic (EDTA) and diethylene-triaminepentaacetic (DTPA) acids in sewage treatment plant (STP) and paper mill effluents has been developed. The chelating acids were extracted by solid-phase extraction cartridges packed with strong anion-exchange resins and were eluted by a small volume of 16 M formic acid. After conversion into their 1-propyl esters, the acids were quantified by gas chromatography using a nitrogen-phosphorus-selective detector and confirmed by GC-MS with a mass selective detector. At a pH of 3.5, the recovery of these acids varied from 83 to 104% in water and STP effluent samples fortified to levels from 1 to 1000 μg/1. Based on a concentration factor of 100, the detection limit for these acids was 0.5 μg/1. All three acids were found in STP effluents, although the concentrations were relatively low for EDTA ( 1000 μg/1) of NTA were observed for nearly all primary STP effluents. A large variation in the levels of these acids was observed in the paper recycling mill effluents collected. Although their concentrations were mostly 2500 μg/1) in the effluents obtained from two mills that use this chelating agent to remove metal ions. DTPA was not detected and the concentrations for NTA and EDTA were

Alkaline (kraft) pulping of wood accounts for more than 60% of paper production. Anions critical to the performance of the kraft pulping process are presently determined by wet chemical methods and more recently by ion chromatography. Chemical recovery and liquor regeneration efficiencies are evaluated by monitoring these ions: Cl−, S2O2−3, SO−23, SO−24, S2−, OH−, and CO2−3, Na+ and K+. Capillary ion electrophoresis is a novel analytical technique that is optimized for the rapid monitoring of charged species. The technique is applied for the first time on kraft process streams using indirect UV detection at 254 nm and 214 nm to monitor the charged species. The results are used to evaluate important process variables such as sulfidity (white liquor), reduction efficiency (recovery furnace performance), and causticization efficiency (slaker performance). This paper presents results obtained by off-line monitoring of ions found in the white, black and green liquors from kraft mills. The potential of capillary ion electrophoresis as a cost effective technique for rapid process processing of kraft pulping liquors is suggested.

A thin-layer chromatographic method for analytical separation and detection of the main component groups in extracts of wood, pulp and paper was designed. The method separates fatty acids from resin acids, which has not been reported in earlier studies. Neutral extractives were separated into sterols, triglycerides and steryl esters. The method proved to be useful for troubleshooting and production control and a number of applications are given.

Resin acids in effluent from a paper mill situated on the upper Derwent Estuary near Hobart, Tasmania (Australia) were determined by HPLC analysis of their 7-methoxycoumarin-4-yl and 7-acetoxycoumarin-4-yl methyl esters. Total concentrations ranged from 1.0 to 4.8 mg 1−1 with a mean of 2.7 mg 1−1 during 1991–1992. Capillary GC-flame ionization detection and GC-MS analyses of organic constituents in river waters collected in April 1992 confirmed the presence of resin acids derived from the paper mill effluent, but the concentrations were highly variable and strongly influenced by freshwater flow and tidal movements. At a site just 500 m downstream of the effluent discharge, concentrations ranged from

Polyamidoamine-epichlorohydrin wet-strength resins for paper contain small amounts of 1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol formed by side reactions from epichlorohydrin used in the production process. Normally some residues of these substances are transferred to the wet-strength treated paper. An analytical method has therefore been developed for the simultaneous determination of 1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol in paper in the 0.05–2 mg/kg range. The compounds are simultaneously extracted and silylated with a solution of N , O -bis-(trimethylsilyl)trifluoroacetamide in acetonitrile and finally determined by capillary gas chromatography-mass spectrometry in the selective ion monitoring mode against an internal standard. The detection limits are 0.04 mg/kg for both 1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol.

p -Dihydroxyborylphenylalanine behaved as an anion in aqueous 0.1 mol dm −3 oxalic acid and 0.1 mol dm −3 citric acid in paper electrophoresis, but as a cation in aqueous 0.1 mol dm −3 fumaric, malic, tartaric, succinic, maleic and malonic acid. A similar electrophoretic behaviour was observed for boric acid. These results indicate that dihydroxyboryl compounds form complexes with oxalic and citric acid. The complex formation was confirmed by the infrared spectra of boric acid in the two aqueous carboxylic acids. The spectral behaviour was fully consistent with the migration behaviour in paper electrophoresis. It was confirmed that paper electrophoresis is a useful technique for determining the chemical states of a compound in solution.

The chromatographic behaviour of 50 cations on titanium (IV) tungstate-impregnated papers in 10−5−5 M HNO3, butanol-8 M HNO3 and HNO3-acetone-water systems was studied, together with the effect of pH on RF values. For most cations, RF = a + bC2, where C is the nitric acid concentration. The effect of mole fractions of HNO3, acetone and water on RF values is explained. A large number of analytically important binary and ternary separations are reported. Quantitative separation of Pb2+ and Hg2+ from binary mixtures containing larger amounts of other metal ions was achieved.

The separation of different uronic acids, oligogalacturonic acids and neutral sugars by electrophoresis on silylated glass-fibre paper is described. As electrolytes 0.1 M solutions of barium, zinc and calcium acetate were used. In these solutions the separation of acid constituents was possible without interference from neutral sugars. Depending on the electrolytes, a mixture of galacturonic, mannuronic, glucuronic and guluronic acid was separated within 90–165 min. The partial characterization of acid polysaccharides such as pectin, alginate and mixtures thereof is described.

The suitability of silylated glass-fibre paper as a supporting material for the electrophoresis of sugars and hydrolysates of polysaccharides has been studied. Because of the absence of molecular sieving effects by the supporting material, the separation is based only on differences in the molecular charge of the samples. The method described allows the separation of low- and high-molecular-weight substances in the same run. A mixture of seven sugars was separated into single components within 45 min. To demonstrate the versatility of the method, various polysaccharide hydrolysates were separated electrophoretically. As electrophoresis is based on a different separation principle than chromatographic techniques, this method is considered to be an efficient alternative and/or complement to the chromatography of carbohydrates.

The paper chromatography of phenols (expecially phenolic acids), aglycones, glycosides and certain sugars is carried out with two new solvents. The authors have also examined these substances with the aid of paper electrophoresis and a borate buffer. A detection reagent for o -diphenols on paper is described.

An aqueous solution of sodium molybdate has been used as a specific reagent for the detection of phenolic compounds with o-dihydroxy groupings. The paper electrophoretic behaviour of phenolic compounds has been studied using a series of different buffers with pH values ranging from 5.2 to 10.0. o-Dihydroxy compounds can readily be detected by the use of ammonium molybdate buffer, and other structural features can be revealed by the choice of suitable electrolyte solutions. Paper partition chromatography of phenolic compounds using molybdate-treated paper in described.

The paper chromatography of vat and sulphur dyes, using reducing solvents at 80°, has been carried out, the dyes being separated as their leuco compounds. In both cases ascending paper chromatography was applied. The relation between dye constitution and chromatographic behaviour has been examined.

A number of simple chromatographic applications are described in which sheet paraffin or other plastic film is used as an adhesive vapor barrier: 1. A funnel attached to a paraffin-enclosed narrow paper wick for spotting large volumes of sample solution as small spots of controlled size. 2. A funnel for the elution of a spot and its reapplication to another paper in a single operation. 3. A method for elution or chromatography which requires no jars or other rigid saturation chambers.

The design and manipulation of an apparatus for centrifugal acceleration of paper chromatography has been described. The main novel features consists of using filter paper strips instead of circular sheets and a constant flow solvent reservoir enclosed in the chromatography tank. Our arrangement is particularly suited for the quantitative analysis of materials labelled with radioactive isotopes of short half-lives and examples are given of the separation of some 82 Br- and 131 I-labelled substances. Advantages of the above method over circular paper chromatography are discussed.

Food preservatives—sorbic, benzoic, p-hydroxybenzoic acid and p-hydroxybenzoates—have been extracted from foods directly on to chromatographic paper with ethyl ether. Paper chromatographic separation of the extracted compounds was effected on the same paper. Methyl, ethyl and propyl p-hydroxybenzoates have been separated from each other during ether extraction and from the critical pair, the butyl and benzyl p-hydroxybenzoates, on a paper impregnated with sodium hydroxide. An examination was made of the reactions which distinguish sorbic and benzoic acids when both are present.

A technique has been developed by which complex mixtures of amines can be sepated by column chromatography on the ion exchange resins Amberlite CG-50 and Amberlite CG-120. Identification of amines is made on the basis of the speed of their elution from the resin column, as well as by subsequent paper chromatography of effluent fractions. The method can be applied to amines derived from various physiological fluids, and offers the possibility of isolating unidentified compounds for chemical characterization. Using the combined technique of ion exchange column chromatography followed by paper chromatography, 26 amines were identified in human urine. these were: methylamine, dimethylamine, ethylamine, ethanolamine, β-hydroxypropylamine, pyrrolidine, piperidine, putrescine, cadaverine, 2,2'-dithiobis(ethylamine), histamine, N-acetylhistamine, i -methylhistamine, p -hydroxybenzylamine, 3-methoxy-4-hydroxybenzylamine, p -tyramine, m -tyramine, octopamine, synephrine, 3-methoxytyramine, normetanephrine, metanephrine, tryptamine, serotonin, bufotenin, and kynuramine. An additional 20 unidentified bases, presumably amines, were found to be regularly excreted in urine. Evidence is presented supporting the identification of kynuramine, β-hydroxy-propylamine, putrescine, cadaverine, and 2,2'-dithiobis-(ethylamine). These 5 amines have not previously been considered to be constituents of normal human urine. It is suggested that study of the urinary excretion of amines may provide useful clues as to the mechanisms involved in various metabolic disorders, including those characterized by mental dysfunction.

Three products formed during the paper chromatography of glycine with water-saturated phenol as a solvent have been investigaetd. These unknowns were stable condensation products whose formation was dependent upon the presence of glycine ad formaldehyde. They were ninhydrin sensitive. Alkaline hydrolysis yielded glycine. For chromatographic practices, the amount of glycine or formaldehyde which may be converted into the condensation products will depend upon the amount of the other component in the mixture. Addition of 1% formaldehyde normally complexes all of the glycine. In usual chromatographic experiments part of the glycine may be complexed by residual formaldehyde present in chromatographic phenol. Glycine condensation may be minimized by redistilling the phenol solvent with aluminum turnings and sodium bicarbonate and by washing the filter paper with 1% oxalic acid.

A wide range of Δ 4 - and Δ 1 , 4 -3-ketosteroids, from weakly polar to strongly polar, may be chromatographed and detected on cellulose triaacetate paper, with benzene—methanol—water mixtures as developing solvents. Three systems have been worked out. In the first a one-phase mixture of benzene, methanol and water is used as the mobile phase and the paper is not accommodated. A “reversed phase” type of chromatogram is obtained, i.e. the more polar compounds have higher R F values than the less polar ones, as is usual for chromatography on acetylated paper. If, howerver, two-phase mixtures of benzene, methanol and water are used, as was the case in the other two methods, “reversed phases”, as well as “convetional” type chomatograms may be obtained. This depeds upon whether the lower or the upper layer is used as the mobile phase, the other layer being used for accommodation of the paper. Perhaps the first-mentioned method should, in contrast to the other two, be regarded as adsorption chromatography, rather than as partition chromatography. Well-reproducible R F values are obtained and, especially with the two-phase mixtures, compact spots are found. Detection methods and R F dta are given for various Δ 4 - and Δ 1 , 4 -3- ketosteroids, ranging from C 18 to C 27 compounds and including sex hormones and adrenoccortical hormones.

1. Low voltage paper electrophoresis in 0.05 M citrate buffer of pH 4.8, at a voltage of 200 V, for 312 hours, is a suitable method for determining adenine nucleotides in erythrocytes. 2. Before applying the sample to the paper it is necessary to remove the excess of deproteinisation agent. 3. By means of the method described 42.6 ± 14.5 mg% ATP and 10.7 ± 9.5 mg % ADP were determined in the erythrocytes.

A critical review of the paper chromatography of Strychnos alkaloids has led to the following conclusions: 1. Paper chromatography is one of the most important methods of approach in elucidating the chemistry of Strychnos alkaloids. 2. Paper chromatography and electrophoresis, in the case of Strychnos tertiary alkaloids, are of great value for the rapid analytical identification of the various compounds. In the case of quaternary alkaloids these methods can give general information, but no absolute conclusions, about a great number of alkaloids so far known of this group, and facilitate the identification of some of the more common bases. 3. No absolute relation between RM value and structure can so far be derived from the RC values of Strychnos alkaloids. This is due to the extremely complicated structures of these alkaloids, which belong to several chemical groups, and to the difficulty of obtaining standard RC values for many quaternary alkaloids. 4. Paper electrophoresis of Strychnos tertiary alkaloids is of great importance for the identification of the different strychnine derivatives. 5. Paper chromatography and electrophoresis must be considered as the best methods hitherto used for the preparative purification of small quantities of Strychnos quaternary alkaloids.

A silicic acid paper chromatographic method for the separation of four major classes of cholesterol esters, namely saturated cholesterol esters, cholesterol oleate, cholesterol linoleate and cholesterol linolenate plus cholesterol arachidonate is described. This method uses a benzene-hexane solvent. The use of combined column and paper chromatography as well as gas chromatographic analysis is presented for definitive identification of the various spots. The predominance of cholesterol linoleate in human plasma, and cholesterol arachidonate in rat plasma is confirmed.

Inorganic anions were studied by paper electrophoresis and ion-exchange paper chromatography employing electrolytes and eluents with various metal ions (Mg2+, Al3+ and Cd2+). It was found that the metal ion has a strong effect on the movement of anions in paper electrophoresis both by ion pair and complex formatin In ion-exchange paper chromatography the effect is small. Data are given for twenty inorganic anions.

The behaviour is described of several barbiturates when subjected to chromatography on filter paper impregnated with olive oil. Results are given for various methanolic and aqueous inorganic solvents. The technique affords a fairly rapid separation of slow-, medium- and quick-acting barbiturates but the order of separation is different from those obtained with conventional and ion-exchange paper chromatography.

Assumptions concerning the similarity of paper chromatography and paper electrophoresis as regards the nature of the interaction of the substances analysed with the immobile phase were verified. glueckauf's method for constructing distribution isotherms from chromatographic measurements was applied to electrophoretic measurements. It was proved that the isotherms obtained in this way are identical with the isotherms obtained by the direct method, when the dependence of the mobility in free solution on the concentration can be neglected. The values of RF, the electrophoretic mobility in free solution Uo and the velocity uo obtained both by direct measurement and by calculation were proved to be identical.

The possible degradation of tryptophan and seven of its metabolites during and after paper chromatography with n-butanol-acetic acid-water has been investigated. It has been found that extensive degradation results from developing and drying the chromatograms at temperatures over 27° and storing them in room light for extended periods before the second development. Lesser amounts of degradation were found after limited exposure of compounds to ultraviolet light between developments and occasionally with the use of unwashed paper. Procedures to eliminate degradation have been described.