Simultaneous Extraction and Determination of Volatile Organic Compounds and Semi-volatile Organic Compounds in Indoor Air Using Multi-bed Solid Phase Extraction Device.

A method for the simultaneous extraction and determination of indoor volatile compounds, including volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), was developed using a multi-bed solid phase extraction (SPE)-type collection device. The collection device was prepared by packing styrene-divinylbenzene polymer particles and activated carbon particles. The collected analytes were completely desorbed by passing 7 mL of acetone, and the solvent was then injected into a gas chromatograph-mass spectrometry without the concentration process. Because the proposed method does not require ultrasonication and a concentration process of eluted solvent, quantitative determination of a relatively volatile compound could be achieved. The total recovery including extraction and elution recoveries for all the investigated analytes were in the range from 91.6 to 109%. The limit of quantification was less than 4.0 ng L-1 for all the investigated analytes, and relative standard deviations of the peak area of the analytes in indoor air were less than 12%. The collection device could be reused for over 50 samplings.

Quantitative Determination of 2-Ethyl-1-hexanol, Texanol and TXIB in In-door Air Using a Solid-Phase Extraction-type Collection Device Followed by Gas Chromatography-Mass Spectrometry.

In this study, in-door air semi-volatile organic compounds (SVOCs) including 2-ethyl-1-hexanol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (texanol), and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), which are scheduled for adding as regulated compounds concerning indoor air reference values in Japan, were quantitatively extracted using a solid-phase extraction-type collection device, followed by sensitively determined by gas chromatography-mass spectrometry. The developed method has shown a good extraction recovery up to an air sampling volume of 900 L. The extracted analytes were quantitatively and rapidly eluted by 7 mL of acetone. The limit of quantification of the analytes were 0.7, 2.1 and 0.2 ng L-1 in air sample at a sampling volume of 300 mL without any concentration of a desorption solvent. The developed method was applied to simultaneous determinations of the investigated target analytes and phthalate esters in real indoor air samples.

Quantitative Determination of Phthalate Esters from Air Samples Using a Solid-Phase Extraction-type Collection Device.

In this study, a solid-phase extraction-type collection device, with styrene-divinylbenzene polymer particles (Sunpak-H) as the adsorbent, was used for the quantitative determination of phthalate esters in air samples. The collection and elution recoveries of eight volatile phthalate esters, i.e., dimethyl phthalate, diethyl phthalate, dipropyl phthalate, diisobutyl phthalate, dibutyl phthalate, butyl-benzyl phthalate, di(2-ethylhexyl) phthalate, and dioctyl phthalate, were quantitatively evaluated. All analytes were collected using the device up to a sampling volume of 10000 L at a sampling temperature of 35°C without breakthrough. During air collection, moisture was not trapped on the adsorbent. The collected analytes were completely eluted from the device by passing 3 mL of acetone. The eluted solvent was injected into a gas chromatography-mass spectrometry system after the eluted solvent was concentrated, if necessary. After washing the adsorbent using acetone, the device could be reused more than 50 times. The limit of quantification for the analytes was less than 1 ng L-1 in air at a sampling volume of 600 L with solvent concentration. This device was successfully applied for the quantitative determination of phthalate esters in real air samples, including indoor and in-car air.

A Newly Designed Solid-Phase Extraction-type Collection Device for Precise Determination of Polycyclic Aromatic Hydrocarbons in Air.

A newly designed styrene-divinylbenzene copolymer adsorbent packed solid-phase extraction (SPE)-type collection device for the quantitative determination of airborne polycyclic aromatic hydrocarbons (PAHs) containing two to five rings is reported in this manuscript. This SPE-type collection device offers rapid, easy and quantitative elution of the analytes and easier reuse. A small collection device was initially developed for investigating the basic collection and elution performances of the adsorbent with respect to PAHs. The analytes were quantitatively collected on the adsorbent up to 3 m3 of air sampling at a sampling temperature of 35°C. The collected analytes were then completely eluted from the adsorbent by passing 3 mL of dichloromethane without carry-over of the analyte. During air collection, because no moisture was trapped on the adsorbent, the subsequent gas chromatography-mass spectrometric analysis was not influenced by moisture. Based on these successful performances, a wide-bore collection device was introduced for collecting larger air samples. After a quantitative investigation of the collection and elution performances of the wide-bore collection device, it device was successfully applied for precise determinations of PAHs in atmospheric air. Further application and employment of the device for the precise determination of semi-volatile organic compounds in environmental air samples is expected due to these excellent results.

Polydimethylsiloxane-coated partitioning sample collection device for the precise quantification of polycyclic aromatic hydrocarbons in air.

A novel partitioning collection device comprising a glass cartridge packed with poly(dimethylsiloxane)-coated macroporous silica particles was developed for the precise quantification of polycyclic aromatic hydrocarbons in air. The analyte collection and elution performances achieved using different amounts of poly(dimethylsiloxane) coating were quantitatively evaluated. The sample retention power increased with increasing the coating, and more than 250 L of air could be collected without analyte breakthrough at a sampling temperature of 35°C. During the air collection, the moisture in the air was not retained on the particles due to the hydrophobic surface of the sorbent. A complete and rapid elution of the collected analytes from the device was accomplished by the passage of only 10 mL of acetone with ultrasonication for 1 min. The proposed method was successfully applied for the determination of airborne polycyclic aromatic hydrocarbons in tunnel air.

Partitioning sample collection/solvent extraction cartridge packed with octadecyl-derivatized macroporous silica particles for the analysis of sesquiterpenes in air samples.

A novel sampling device based on the partition of target analytes to the extraction medium was developed for the determination of sesquiterpenes in air samples. The extraction medium was prepared by the chemical derivatization of a specially prepared macroporous silica, with a specific surface area of 2.0 m2 /g. Taking advantage of the sample extraction, which was mainly based on the partition of sesquiterpenes between air and a C18 -bonded phase, the extracted analytes were rapidly and quantitatively desorbed just by passing a small amount of desorption solvent for subsequent analysis by gas chromatography with mass spectrometry. Several experimental conditions, such as the sampling volume and temperature, were systematically evaluated. Under optimized conditions, desorption of the extracted analytes was completed within 1 min with a desorption efficiency of more than 99.9%, achieved using 5 mL of acetone for all the evaluated sesquiterpenes. The applicability of the developed device was confirmed by the determination of several sesquiterpenes from coniferous trees. Although further improvements of the device are required for collecting large volumes or high-temperature air samples, the potential of the developed sampling device was confirmed by determining traces of semivolatile organic compounds in air samples.

Metrological effectiveness of an analytical method for volatile organic compounds standard materials using post-column reaction GC/FID system.

The metrological effectiveness of an analytical method using the post-column reaction GC/FID system was evaluated. The SI-traceable certified reference material (CRM), the eight ester phthalates mixture standard solution, was used as a sample. We assigned specific value to n-eicosane and it was used as an internal standard. A known quantity of n-eicosane was added to the CRM, and the mixture was measured with the post-column reaction GC/FID system. Six phthalate esters were chromatographically separated and determined. The assigned values by our system are in good agreement with the certified values of the CRM, and the combined uncertainties of the measurements by the present system were better than those of the CRM. Our method is classified as a primary ratio method and the specific values of many organic compounds can be assigned very precisely by using a small number of reference materials. Also, the method can make it possible to avoid the purity determination of raw materials and directly to assign their specific values after the preparation of the standard mixture. Conclusively, this post-column reaction GC/FID system is very effective for the chemical metrology.

Calibration of an evaporative light-scattering detector as a mass detector for supercritical fluid chromatography by using uniform Poly(ethylene glycol) oligomers.

The quantitativeness of an evaporative light-scattering detector (ELSD) for supercritical fluid chromatography (SFC) was evaluated by using an equimass mixture of uniform poly(ethylene glycol) (PEG) oligomers. Uniform oligomers, in which all molecules have an identical molecular mass, are useful for the accurate calibration of detectors. We calibrated the SFC-ELSD system for various concentrations and molecular masses by using an equimass mixture of PEG oligomers. ELSD not only showed a good linear response to the injected concentration over a wide concentration range, from 10(-4) to 10(-1)g/mL, but also showed a strong dependence on the molecular mass of the solute. By using chromatograms of the equimass mixture of uniform oligomers to calibrate SFC-ELSD, it was possible to determine exact values of not only the average mass but also the molecular-mass distribution for a PEG 1540 sample. The average molecular mass was shifted to a higher value by several percentage points after calibration of the ELSD.

Development of analytical methods for polycyclic aromatic hydrocarbons (PAHs) in airborne particulates: a review.

In the present work, the different sample collection, pretreatment and analytical methods for polycyclic aromatic hydrocarbons (PAHs) in airborne particulates is systematacially reviewed, and the applications of these pretreatment and analytical methods for PAHs are compared in detail. Some comments on the future expectation are also presented.

Solid-phase extraction with C30 bonded silica for analysis of polycyclic aromatic hydrocarbons in airborne particulate matters by gas chromatography-mass spectrometry.

A solid-phase extraction (SPE) method using triacontyl bonded silica (C30) as sorbent was developed for the determination of 16 US Environmental Protection Agency polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matters quantitatively by gas chromatography-mass spectrometry (GC-MS). Optimization experiments were conducted using spiked standard aqueous solution of PAHs and real airborne particulates samples aiming to obtain highest SPE recoveries and extraction efficiency. Factors were studied in SPE procedures including the concentration of organic modifier, flow rate of sample loading and elution solvents. The ultrasonication time and solvents were also investigated. Recoveries were in the range of 68-107% for standard PAHs aqueous solution and 61-116% for real spiked sample. Limits of detection (LODs) and limits of quantification (LOQs) with standard solution were in the range of 0.0070-0.21 microgL(-1) and 0.022-0.67 microgL(-1), respectively. The optimized method was successfully applied to the determination of 16 PAHs in real airborne particulate matters.

Simplification of determination method for standard materials using post-column reaction GC/FID.

For the simple and fast preparation of highly reliable standard materials, a post-column reaction GC/FID system was developed and evaluated on the mixture of oxygen-containing organic compounds. The oxygen-containing organic compounds mixing solution were determined with the post-column reaction GC/FID system using n-dodecane as an internal calibration standard. Required value of relative expanded uncertainty as an original source of SI-traceable standard materials was within 1% and it aimed at this value as accuracy of the quantitative analysis. The results showed good agreement between the prepared concentrations and analytical values using post-column reaction GC/FID system. These results indicated that the post-column reaction GC/FID system would be used for getting SI-traceable values.

Monitoring nano-flow rate of water by atomic emission detection using helium radio-frequency plasma.

Recently, high-performance nano-scale flow pumping systems have been developed for micro and miniaturized analysis systems. A novel device capable of measuring and monitoring nanoliter scale flow rates has been required for the further development of the pumping system. In this study, an atomic emission detector using helium radio-frequency plasma (RFP-AED) was used for the measurement of the nanoliter scale flow rate of water by quantitatively detecting the emission from hydrogen in the water molecules. Monitoring nano-flow rates of water in the range up to 1.0 microl min(-1), and the change in the flow rate by the indication of the ratio of the emissions of H (656.3 nm) and He (667.8 nm) were successful. At present, the lowest flow rate that could be determined reproducibly was 4 nl min(-1) calculated as five times the standard deviation of the background noise. Additionally, similar evaluations for the deviation of each flow rate by using the RFP-AED and a flow-injection system were produced.