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This study developed a rapid screening method to determine residual solvents contained in a tablet formulation using a needle-type extraction device. For this, the tablet formulation was pulverized and the powdered sample was rapidly inserted into a pipette tip. After fixing the sample with quartz wool, the pipette tip was capped with a silicon septum. A needle-type extraction device packed with Carbopack X and a carbon molecular sieve was inserted into the pipette tip through the septum, and the gas sample was collected. During this gas sampling, pure N 2 gas was introduced into the pipette tip. The extraction time for collecting 100 mL of the sample was approximately 10 min. After gas sampling, the extraction needle was connected to a gas-tight syringe and 0.5 mL of pure N 2 gas (desorption gas) was collected. The extraction needle was then inserted into a heated gas chromatographic injection port. The extracted residual solvents were then thermally desorbed and determined using a gas chromatograph-flame ionization detector. The detector response is very low for carbon tetrachloride, although the proposed method showed sufficient sensitivity for five Class 1 compounds. Additionally, this study clearly indicated that the purge efficiency of residual solves with dynamic extraction is different between powdered pharmaceutical formulations., (© 2024. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

An analytical method for quantifying the volatile anticancer drugs ifosfamide (IF) and cyclophosphamide (CP) in air was developed on the basis of thermal desorption (TD)-gas chromatography-mass spectrometry. Polydimethylsiloxane-coated macroporous silica was used as the adsorbent. The extraction tube was prepared by packing 0.2 g of adsorbent particles into a glass tube. The extraction and desorption efficiencies of the proposed method were quantitatively investigated in this study. The limits of detection of the proposed method for IF and CP were 3.3 ng L -1 at an air sampling volume of 3.0 L (30 min). The sensitivity of the proposed method was compared with using a Tenax TA packed tube that is widely used as the extraction medium in TD analysis. Finally, detection of IF and CP that evaporated from aqueous standard solution was investigated., (© 2023. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

A simple screening analytical method for determining the emission of volatile organic compounds (VOCs) from household materials was developed using a solid-phase extraction (SPE)-type collection device and a gas sampling bag. The VOCs emitted from the sample material placed in the gas sampling bag with a volume of 20 L were extracted on the SPE-type collection device. In this study, complete sampling mode was developed in addition to a conventional flow sampling mode. The extracted VOCs were then eluted with 8 mL of acetone and measured using gas chromatography-mass spectrometry. The proposed method does not require a stainless-steel chamber and a thermal desorption system; therefore, VOC emission from household materials could be easily evaluated with an affordable cost, suggesting that the method is suitable for the screening technique for evaluating VOC emission from solid materials., (© 2023. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Ifosfamide (IF), cyclophosphamide (CP), and bendamustine (BD) are widely used anticancer drugs. These drugs have slight volatility; therefore, medical-staff exposure is of concern in the medical field. However, an accurate and quantitative detection method of these volatile drugs in air has not been reported. In this study, we developed the quantitative extraction and detection method of these volatile anticancer drugs in air. For the extraction of analytes, a solid-phase extraction-type collection device packed with styrene-divinylbenzene polymer particles was used. The extracted analytes were quantitatively eluted with 5 mL of ethanol, and the solution was concentrated to 100 μL with nitrogen purging. The analytes were analyzed using gas chromatography-mass spectrometry (GC-MS). The limit of detection of the proposed method for IF and CP was 0.017 and 0.033 ng L -1 , respectively in air at an air sampling volume of 300 L. IF and CP showed slight volatility, whereas BD was not detected in GC-MS due to its lower volatility. The spiked recoveries of IF and CP in the proposed method were within the range of 95.5 to 101%. Finally, the proposed method was applied to determine the exposure of IF and CP during the dispensing of CP within a hospital dispensary room. The investigated volatile anticancer drugs were not detected in real air samples, indicating that the protection measures employed are sufficient.

A novel extraction medium was developed by packing polyethylene terephthalate (PET) nanofiber sheet having a diameter of 500 nm into a stainless-steel capillary of 0.8 mm inner diameter. The nanofiber was prepared by a carbon dioxide (CO 2 ) laser supersonic multi-drawing method, which has a significantly higher surface area than the original PET fiber. A nanofiber sheet was prepared by winding the nanofibers. Extraction of phthalates in water samples by a PET nanofiber-packed extraction capillary was investigated using a conventional high-performance liquid chromatography (HPLC). Water samples were introduced into the extraction capillary with a low pressure. After extracting the water sample, the extraction capillary was directly connected to a six-port valve of HPLC with a PEEK nut, and the extracted analytes were desorbed, followed by injection to an HPLC system using a small amount of organic solvent. In this manuscript, the fundamental performance of the nanofiber sheet-packed extraction capillary for the extraction of organic compounds in water samples is quantitatively evaluated using a conventional HPLC system.

This manuscript describes the determination of ammonia (NH 3 ) in aqueous samples by purge-and-trap extraction using a needle-type extraction device with gas chromatography-barrier discharge ionization detector (GC-BID). NH 3 was purged from the aqueous samples in basic conditions and then salted out with sodium chloride. Purged ammonia was trapped onto non-volatile carboxylic acid-coated macroporous terephthalic acid particles, which were contained within the needle-type extraction device. The analyte (NH 3 ) was thermally desorbed by heating the extraction needle in the GC injection port, and detected by BID. After the optimization of both purge and extraction conditions, the linearity and sensitivity of the proposed method were evaluated. The limit of detection was found to be 2.0 mg L -1 at a headspace sampling volume of 100 mL. The method applicability was confirmed by the determination of spiked NH 3 in tap water and river water samples.

A purge-and-trap method using a needle-type extraction device and a gas chromatography-barrier discharge ionization detector for the analysis of formic (FA) and acetic acids (AA) in aqueous samples is presented. An activated carbon-based adsorbent, Carboxen 1000, was employed as the extraction medium for the needle-type extraction device. The sampling time was 5 min for collecting headspace gas in a glass vial, including 10 mL of an aqueous sample. The detection limits for FA and AA with a headspace sampling volume of 100 mL were 3.3 and 2.0 mg L -1 , respectively. Since the proposed method was based on purge-and-trap collection, it was suitable for the determination of aqueous FA and AA in complex matrices with simple and rapid sample preparation steps. The proposed method was applied to the determination of FA and AA in fruit juice samples and FA generated by the electrochemical reduction of carbon dioxide.

A novel analytical method for determining formaldehyde (FA) in aqueous samples was developed with a miniaturized extraction capillary in high-performance liquid chromatography (HPLC). The extraction capillary was prepared by packing silica gel particles in a stainless steel capillary of 0.8 mm i.d. and 1.6 mm o.d. A derivatization reagent of 2,4-dinitrophenylhydrazine (DNPH) was impregnated on the silica gel particles by pumping a solution of DNPH to the capillary. Two extraction methods; dynamic extraction and purge-and-trap (PT) methods, were investigated for derivatizing and extracting FA from water samples onto the silica gel in the extraction capillary. The extraction capillary was directly connected to a six-port valve, and then desorption of the derivative from the capillary and injection to conventional HPLC system were simultaneously achieved with a flow of acetonitrile through the capillary. In the dynamic extraction, FA was determined with a simple sample preparation procedure, and the limit of detection (LOD) was 18 μg L(-1) at a sample volume of 20 mL, while several limitations were found in the method, such as bleeding of the derivatization reagent and the corresponding derivatized FA from the capillary during the sample load/extraction process. The sensitivity was significantly improved by introducing a PT technique, where the LOD was 6.9 μg L(-1) at a sample volume of 20 mL with a sampling time of approximately 20 min. With the PT method, successful recoveries of FA were confirmed for spiked tap water, river water and fruit juice samples.

A bundle of polymer-coated filaments was successfully introduced as an extraction medium for the preconcentration of an aqueous solution of aromatic compounds. The extraction was simply carried out with pumping the aqueous sample solution to the extraction capillary at ambient temperature. The extracted analytes were sequentially eluted with a flow of pure water using temperature-programmed heating of the extraction capillary in an oven. The results clearly suggest that the polymer-coated fiber-packed capillary could be employed in the sample preparation process for the analysis of various aqueous samples. Introducing the fractions eluted from the fiber-packed capillary to a conventional microcolumn liquid chromatography (micro-LC) system via a home-made valve-based modulator, an on-line coupled extraction/separation system was developed and a possibility to a pseudo-two-dimensional (pseudo-2D) LC separation of aromatic compounds in aqueous matrices has also been demonstrated.

A novel method for evaluating the thermal catalytic decomposition of organic compounds on a solid acid catalyst was developed using a capillary gas chromatography-flame ionization detector (GC-FID) equipped with a packed-capillary column. The thermal catalytic decomposition of various organic compounds was investigated by introducing gaseous or liquid organic compounds into a heated test tube packed with TiO2 particles. The resulting carbon monoxide (CO) and carbon dioxide (CO2) in the test tube were determined in a conventional capillary GC system with a methanizer after separation on a packed-capillary column. In the packed-capillary GC system, several parameters affecting thermal catalytic reactions of various organic compounds were successfully evaluated, such as the type of the catalysts and the effect of catalytic temperatures. Finally, a sequential decomposition of organic compounds was confirmed in the heated reaction tube packed with TiO2 particles.

A needle-type extraction device is one of the promising sample preparation devices for the gas chromatographic (GC) analysis of various organic compounds. The most remarkable advantage of this device is a simple and rapid desorption of the analytes by direct insertion of an extraction needle into a conventional GC injection port. In this review, fundamental aspects of the needle-type extraction devices and its applications for the determination of trace organic compounds, especially volatile organic compounds (VOCs), in several sample matrices are described.

The musty-odor compounds (MOCs) 2-methylisoborneol (2-MIB) and geosmin in water samples were determined by a purge-and-trap method using a needle-type extraction device followed by gas chromatography-mass spectrometry. For the extraction of these compounds, a triple-layer-type extraction needle containing divinylbenzene and activated carbon particles as the particulate extraction media was introduced. Several experimental parameters, including the sample temperature during extraction, the addition of sodium chloride, and desorption conditions, were thoroughly optimized in this study. The detection limits for 2-MIB and geosmin were 1.0 and 0.5 ng L(-1), respectively. The method was successfully applied to the simultaneous determination of MOCs and other volatile organic compounds in tap-water samples.

Carbon monoxide (CO) and carbon dioxide (CO2) were determined in a conventional capillary gas chromatography-flame ionization detector (GC-FID) by introducing a packed-capillary column and a methanizer. Due to good compatibility with rapid temperature-programmed operation of the packed capillary column, several volatile compounds, including CO and CO2, were rapidly eluted along with satisfactory resolution and sample loading capacity. The limit of quantifications of CO and CO2 were 5 and 3 ppm, respectively, with an injection volume of 0.5 mL. The developed system was then successfully applied to evaluating the photocatalytic decomposition of volatile organic compounds on titanium dioxide (TiO2).

A rapid on-site air sampling technique was developed with a miniaturized needle-type sample preparation device for a systematic evaluation of the indoor air environments in school facilities. With the in-needle extraction device packed with a polymer particle of divinylbenzene and activated carbon particles, various types of volatile organic compounds (VOCs) were successfully extracted. For evaluating the indoor air qualities in school facilities, air samples in renovated rooms using organic solvent as a thinner of the paint were analyzed along with measurements of several VOCs in indoor air samples taken in newly built primary schools mainly using low-VOCs materials. After periodical renovation/maintenance, the time-variation profile of typical VOCs found in the school facilities has also been monitored. From the results, it could be observed that the VOCs in most of the rooms in these primary schools were at a quite low level; however, a relatively higher concentration of VOCs was found in some specially designed rooms, such as music rooms. In addition, some non-regulated compounds, including benzyl alcohol and branched alkanes, were detected in these primary schools. The results showed a good applicability of the needle device to indoor air analysis in schools, suggesting a wide range of future employment of the needle device, especially for indoor air analysis in other types of facilities and rooms including hospitals and hotels.

By introducing sequentially connected two packed-capillary columns, a wide range of volatile compounds were successfully separated in gas chromatography. The hyphenation of two packed-capillary columns of 1.0 mm i.d. was accomplished using a conventional 6-port valve, where the temperature of each column was individually controlled in the respective column ovens. These columns were prepared with two different types of sorbents, each having a different selectivity, in order to separate a wide range of compounds, including permanent gases, volatile alcohols and other typical volatile organic compounds. With a simple valve switching operation, the complex sample mixtures were rapidly separated and detected.

Retention behaviors of pyrazine and alkylpyrazines on various stationary phases in reversed-phase liquid chromatography were examined. An abnormal temperature effect on the retention of alkylpyrazines with a mobile phase consisting of acetonitrile and water was observed when changing the column temperature. On the other hand, no similar trend was found with a methanol-water mobile phase. For all the columns investigated in this work, the above tendency to the temperature-dependence was consistently observed, suggesting that the abnormal temperature effect on the retention of alkylpyrazines could be mainly induced by an acetonitrile-based mobile phase., (2011 © The Japan Society for Analytical Chemistry)

Novel polymer-coated fiber-packed microcolumns in liquid chromatography (LC) have been developed. Typical polymeric materials, such as polydimethylsiloxane and polyethyleneglycol, which are conventional stationary phases of capillary columns in gas chromatography (GC), have been employed as coating materials onto the surface of fine filaments. Packed longitudinally with a bundle of polymer-coated filaments into a stainless-steel capillary of 0.8 mm i.d., 150 mm length, several types of polymer-coated fiber-packed columns were prepared, and the retention behavior of aromatic compounds on these columns has been studied. A good linear relationship was obtained for van't Hoff plots over the temperature range between 0 and 200 °C, clearly indicating an excellent heat-resistant property of these polymer-coated fibrous stationary phases. Taking advantage of the heat-resistant feature of the fibrous stationary phases, the separation of several test mixtures with temperature-programmed elution was studied, where a solvent gradient program was additionally introduced if needed. Separation was also carried out with pure water as the mobile phase using an appropriate temperature program., (2011 © The Japan Society for Analytical Chemistry)

Third-hand smoking was quantitatively evaluated with a polymer-packed sample preparation needle and subsequent gas chromatography-mass spectroscopy analysis. The extraction needle was prepared with polymeric particles as the extraction medium, and successful extraction of typical gaseous volatile organic compounds (VOCs) was accomplished with the extraction needle. For an evaluation of this new cigarette hazard, several types of clothing fabrics were exposed to sidestream smoke, and the smoking-related VOCs evaporated from the fabrics to the environmental air were preconcentrated with the extraction needle. Smoking-related VOCs in smokers' breath were also measured using the extraction needle, and the effect of the breath VOCs on third-hand smoking pollution was evaluated. The results demonstrated that a trace amount of smoking-related VOCs was successfully determined by the proposed method. The adsorption and desorption behaviors of smoking-related VOCs were clearly different for each fabric material, and the time variations of these VOCs concentrations were quantitatively evaluated. The VOCs in the smokers' breath were clearly higher than that of nonsmokers'; however, the results suggested that no significant effect of the smokers' breath on the potential pollution occurred in the typical life space. The method was further applied to the determination of the actual third-hand smoking pollution in an automobile, and a future possibility of the proposed method to the analysis of trace amounts of VOCs in environmental air samples was suggested.

Novel packed-capillary columns for gas chromatography were developed with a thin-wall stainless-steel capillary of 1.0 mm i.d.; and rapid temperature-programmed separations have been carried out after a basic evaluation concerning the compatibility of these columns to the temperature program. With a numerical integration method, the retention of several test analytes during temperature-programmed elution was successfully estimated. In order to confirm the suitability of the packed-capillary columns to relatively fast temperature programming up to 40 degrees C/min, theoretically predicted retention data were compared with that actually measured. The results suggested a good separation performance of the newly developed packed-capillary columns as a particle-packed column conventionally used. Also, the compatibility to a rapid temperature-programmed operation was quite satisfactory for almost all of the separations currently done in typical analytical laboratories.

Surface derivatization of Kevlar, poly(p-phenylene terephthalamide), fiber has been studied along with the evaluation of the surface characteristics of the chemically-modified fiber as the stationary phase in packed-capillary gas chromatography (GC). Several experimental parameters in the derivatization reaction have been optimized, and the retention behavior of the surface-derivatized fibrous stationary phase has been investigated using various standard solutes, such as alkanes, alcohols and alkylbenzenes. By introducing aminoethyl functional groups onto the surface of the fibrous material, a specific selectivity for polar solutes has been observed.

A novel fire investigation technique using a needle extraction device was studied. Using a polymer particle-packed needle device, air samples containing volatile organic compounds (VOCs) generated from fire accelerants, gasoline and kerosene were extracted effectively, and subsequent gas chromatographic (GC) analyses were successfully carried out. Carpet and wood samples were spiked with gasoline and kerosene, followed by monitoring of the time-variation profiles of emitted VOCs up to 48 h. The fire accelerants were also measured for combusted carpet and wood samples, and the applicability of the proposed method to fire investigations was confirmed. Even at 48 h after spiking, groups of characteristic compounds were clearly observed in the air environments near the combusted sample. This method was further applied to the determination of VOCs in simulated fires, strongly suggesting the applicability of the developed method to real fire investigations.

The development of retention prediction models for the seven ginsenosides (Rf, Rg1, Rd, Re, Rc, Rb2 and Rb1) on a polyvinyl alcohol (PVA)-bonded stationary phase at subambient temperatures is presented. The models were derived using multiple linear regression (MLR) and artificial neural network (ANN) using the logarithm of the retention factor (log k) as the dependent variable. Using stepwise MLR, the retention of the analytes under all temperature conditions was satisfactorily described by a three-predictor model; the predictors being the percentage of acetonitrile (%MeCN) in the mobile phase, the number of hydrogen bond donors (HBD) and the ovality (Ov) of the compounds. These predictors account for the contribution of the solute-related variables (HBD and Ov) and the influence of the mobile phase composition (%MeCN) on the retention behavior of the ginsenosides. The MLR models produced adequate fits, as proven by the high calibration R2 values of the predicted versus the observed log k (> 0.95) and good predictive properties, as indicated by the high cross-validated q2 (> 0.93) and high R2 (> 0.95) values obtained from the test set. ANN modeling was also conducted using the predictors that were derived from MLR as inputs and log k as the output. A comparison of the models derived from both MLR and ANN revealed that the trained ANNs showed better predictive abilities than the MLR models in all temperature conditions as demonstrated by their higher R2 values for both training and test sets and lower average percentage deviation of the predicted log k from the observed log k of the test compounds. The ANN models also showed excellent performance when applied to the prediction of the seven ginsenosides in different sample matrices.

The influence of temperature on the surface structure of the octadecylsilica (ODS) bonded phase was investigated with a molecular dynamics (MD) simulation. The MD simulation was applied to a molecular model consisting of three parts: amorphous silica base, dimethyloctadecylsilyl ligands and n-hexane as a mobile phase solvent. More detailed information on the effect of temperature was obtained at the low temperature region than that reported in our previous study. The motion of ODS ligands could be estimated by the mean square displacement (MSD) of the terminal carbon atoms of ODS ligands. The gauche fraction in the ODS ligand conformation can also be estimated to obtain the ligand conformation for each simulation condition in detail. It can be seen that an elevated temperature induced the more bent ligand conformation. The trend has a good agreement to that of the results experimentally observed by using various spectroscopic techniques such as nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and Raman spectroscopy.

The influence of the mobile-phase composition and temperature on the surface structure of the octadecylsilica (ODS) stationary-phase was investigated by applying a molecular-dynamics (MD) simulation. The molecular model to which the MD simulation was applied consisted of three parts: an amorphous silica base, dimethyloctadecylsilyl ligands and mobile-phase solvents. More detailed information on the effect of the mobile-phase composition was obtained by constructing larger molecular models than those used in our previous study. The thickness of the hydrocarbon layer of the stationary phase could be estimated based on the distance between the carbon atom located at the terminal end of the ODS ligand and the silica gel surface. The structural information obtained by the calculation showed good consistency with the experimentally observed values. The gauche fraction in the ODS ligand conformation could be also estimated to obtain a more detailed ligand conformation for each molecular model. It was found that as the temperature increased, the ligand conformation collapsed more. This trend was the same as the experimentally observed trends obtained by NMR, FT-IR, and Raman spectroscopic techniques.

Fibrous synthetic polymers have been introduced as the support material for packed capillaries in gas chromatography. The filaments of the polymers were packed longitudinally into a fused-silica capillary, followed by the conventional coating process for open-tubular capillaries. With various polysiloxane-based polymeric materials coated onto these filaments, it was demonstrated that the retentivity was significantly improved over conventional wall-coated capillaries of the same length and that the selectivity can be tuned by selecting different coating materials chosen for the various purposes. The results clearly showed the contribution of the fibrous support and the polymer-coating to the retention of analytes. They also showed the bright possibility for a novel usage of fine fibrous polymers as the support material, which can be combined with a newly-synthesized coating materials designed for particular separations.

Miniaturized extraction and separation media have been successfully developed from precisely controlled technologies. In this article, recent developments in these high performance analytical methods, such as miniaturized sample preparation methods and the coupling of these techniques with microscale separation systems, have been reviewed, along with some applications to environmental and biological analysis. The advantage of the miniaturization is not only for the environmental compatibility but also for the developments of the high performance analytical systems. Down-sizing also makes it possible to investigate and introduce various compounds and materials as novel media (such as tailor-made materials and devices) in separation science. As a typical example of the novel miniaturized sample preparation system, the applications of fibrous materials for microcolumn liquid-phase separation methods are described.