Volatile anticancer drug determination by thermal desorption technique with polydimethylsiloxane-coated macroporous silica adsorbent in gas chromatography-mass spectrometry

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.

A urinary biomarker for monitoring exposures to 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate in rats

2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MB) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TMPD-DB) are widely used primarily as surface stabilizers for water-based paints and plasticizers, respectively. Exposure to these compounds has been suspected as being associated with sick building syndrome and allergic diseases such as asthma in general populations. Therefore, it is very important to be able to know the amounts of these compounds absorbed into the body in order to evaluate its adverse effects on humans in living environments. In the present study, the urinary excretion kinetics of TMPD-MB and TMPD-DB were studied in animals to establish for urinary metabolites suitable as biomarkers for monitoring exposure. A single dose (48-750 mg/kg body weight) of TMPD-MB or TMPD-DB was administered intraperitoneally to male Sprague-Dawley rats, and their urine was collected periodically for a week. Two major metabolites, 2,2,4-trimethyl-1,3-pentanediol (TMPD) and 3-hydroxy-2,2,4-trimethylvaleric acid (HTMV), were measured in the urine samples. Their kinetics were evaluated by moment analysis of the urinary excretion rates of the metabolites versus time curves. The urinary excretion amounts of HTMV were suggested to be proportional to the absorption amounts over a wide exposure range of both TMPD-MB and TMPD-DB. The amounts of HTMV accounted for almost the same level, i.e., 4-5% of the dose at the lowest dosage, in rats tested for both TMPD-MB and TMPD-DB. Urinary HTMV was considered to be an optimal biomarker for monitoring exposure to mixtures of these compounds.

Characterization of Cooked Nonglutinous Rice Cultivars Based on Flavor Volatiles and Their Change during Storage

Characterizing fleshly cooked rice cultivars according to the volatile aroma compounds helps consumers select a favorite and is useful for the development of new cultivars that will have a pleasant aroma. In the present study, six Japanese nonglutinous cultivars, which were freshly harvested in 2021, were characterized based on their flavor volatiles after being freshly cooked. In order to extract the volatile compounds just after cooking, the vaporized compounds were extracted for 5 min using a solid-phase microextraction (SPME) fiber and were measured via gas chromatography/mass spectrometry (GC/MS). Multiple comparison tests statistically detected four volatile aroma compounds: 2-pentylfuran, nonanal, 4-vinylphenol, and indole. From among the six rice cultivars tested, the proportions of the latter two compounds showed significant differences, and in principal component analysis of cooked rice, these two best characterized freshly harvested and freshly cooked Japanese nonglutinous rice cultivars; indole was indicative of Nipponbare, and 4-vinylphenol was indicative of Koshihikari and Ichihomare. In the present study, changes in the volatile aroma compounds of the freshly cooked rice cultivars were found to slightly differentiate according to storage times: 2-pentylfuran tended to increase, nonanal first increased and then decreased, and 4-vinylphenol and indole either remained almost unchanged or were only slightly decreased during storage. Therefore, establishing the differences in rice cultivar types revealed that the characteristics of the flavor volatiles of freshly cooked rice after long-term storage significantly depend on how the rice cultivar is stored.

A novel set of volatile urinary biomarkers for late-life major depressive and anxiety disorders upon the progression of frailty: a pilot study

Mood and anxiety disorders are frequent in the elderly and increase the risk of frailty. This study aimed to identify novel biomarkers of major depressive disorder (MDD) and anxiety in the elderly. We examined 639 participants in the community-dwelling Otassha Study (518 individuals considered healthy control, 77 with depression, anxiety, etc.), mean age 75 years, 58.4% of female. After exclusion criteria, we analyzed VOCs from 18 individuals (9 healthy control, 9 of MDD/agoraphobia case). Urinary volatile and semi-volatile organic compounds (VOCs) were profiled using solid-phase microextraction and gas chromatography-mass spectrometry. Six urinary VOCs differed in the absolute area of the base peak between participants with MDD and/or agoraphobia and controls. High area under the receiver-operating characteristic curve (AUC) values were found for phenethyl isothiocyanate (AUC: 0.86, p = 0.009), hexanoic acid (AUC: 0.85, p = 0.012), texanol (AUC: 0.99, p = 0.0005), and texanol isomer (AUC: 0.89, p = 0.005). The combined indices of dimethyl sulfone, phenethyl isothiocyanate, and hexanoic acid, and texanol and texanol isomer showed AUCs of 0.91 (p = 0.003) and 0.99 (p = 0.0005) and correlated with the GRID-HAMD and the Kihon Checklist (CL score), respectively. These VOCs may be valuable biomarkers for evaluating MDD and/or agoraphobia in the elderly.

Extraction of Volatile Anticancer Drugs in Air Using a Solid-Phase Extraction Type Device Followed by Gas Chromatography-Mass Spectrometric Analysis

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.

Effect of surfactin on removal of semi-volatile organic compound: Emphasis on enhanced biofiltration performance

The performance of a lab-scale biotrickling filter (BTF) inoculated with a mixed fungal consortium was investigated for the simultaneous abatement of 2-ethylhexanol; a hydrophobic semi-volatile organic compound (SVOC), and propylene glycol monomethyl ether (PGME). The BTF performance was investigated in the presence of lipopeptide-type biosurfactant, surfactin. The effect of surfactin on the removal efficiency and elimination capacity was examined at stretched inlet loading rates (LR): 1.04 to 15.7 and 3.2-48 g m^-3 h^-1 of PGME and 2-ethylhexanol, respectively. Seeding the BTF with 50 mg L^-1 of surfactin maintained high and consistent removal efficiencies of PGME and 2-ethylhexanol up to LRs of 15.7 and 32 g m^-3 h^-1, with removal efficiencies of 98.5 and 99%, respectively. Once the LR of 2-ethylhexanol increased to 48 g m^-3 h^-1, a substrate inhibition was observed, accompanied by a sudden decrease in removal efficiency from 99.2 to 62.3%. At the same LR, the BTF performance was improved by reseeding 100 mg L^-1 of surfactin, hence, reinstated the removal efficiency of 2-ethylhexanol to 92.7% and achieving a maximum elimination capacity of 44.5 g m^-3 h^-1. This enhanced SVOC uptake rate was further confirmed by a considerable increase in reaction rate constant from 0.005 to 0.017 s^-1. A batch study was also conducted at the end of the experimental run to better understand the correlation between surfactin concentrations and the time-dependent partition coefficient of 2-ethylhexanol. Biofilm microbial community structure revealed relative abundancy of 72 and 28% of Trichoderma asperellum and Fusarium solani, respectively. The findings of this study show for the first time that the removal of a semi-VOC such as 2-ethylhexanol is feasible in the presence of surfactin and hence improving the bioavailability of hydrophobic semi-VOC.

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.

Using SPME-GC/REMPI-TOFMS to Measure the Volatile Odor-Active Compounds in Freshly Cooked Rice

The volatile odor-active compounds of cooked rice were evaluated using a method that combined solid-phase microextraction (SPME) with gas chromatography-resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (GC/REMPI-TOFMS). An SPME fiber was held at the upper levels of the cooked rice and given an extraction time of 5 min. By using a nanosecond ultraviolet (266 nm) pulsed laser for ionization, two compounds, 4-vinylphenol and indole, which are considered to be important for the characteristic flavor of cooked rice, could be detected from all types of cultivars measured in the present study-nonglutinous rice, glutinous rice, and aromatic rice. In the case of fresh nonglutinous rice, the amounts of introduction for 4-vinylphenol and indole to GC were ca. 70 and 20 pg, respectively. While both peak areas decreased with increases in the time needed to maintain warmth, the decreasing behaviors differed slightly with a noteworthy rapid decrease for indole. For nonglutinous rice, the peak areas for 4-vinylphenol were almost the same, whether it was fresh (measured within 1 month from harvest) or aged (measured 6-12 months after harvest), but those of indole significantly decreased following storage. We also found differences among cultivars: the peak area for 4-vinylphenol in nonglutinous rice was somewhat strong; the peak area for indole was intensely strong in glutinous rice; however, the peak areas for both 4-vinylphenol and indole were weak in aromatic rice. Volatile odor-active compounds were detected in a sensitive and time-resolved manner; therefore, the proposed method could be useful for differentiating varieties of cooked rice from the viewpoints of cooking conditions, freshness, and cultivar types.

Portable dehumidifiers condensed water: A novel matrix for the screening of semi-volatile compounds in indoor air

The comprehensive identification of organic species existing in indoor environments is a key issue to understand their impact in human health. This study proposes the analysis of condensed water samples, collected with portable dehumidifiers, to characterize semi-volatile compounds in the gas phase of confined areas. Water samples are concentrated by solid-phase extraction (SPE). The obtained extracts are analysed by gas chromatography (GC) time-of-flight mass spectrometry (TOF-MS), following a non-target screening data mining approach. In first term, spectra of deconvoluted compounds are compared with those in NIST low resolution library; thereafter, tentative identifications are verified using an in-house database of accurate electron ionization (EI) MS spectra. Chromatographic (retention index) and spectral data are combined for unambiguous species identification. The potential of condensed water samples to reflect changes in the composition of indoor atmospheres, the match between data obtained using different dehumidifiers, and the relative concentration efficiency of condensed water compared to that attained by active sampling of moderate air volumes are discussed. A total of 141 semi-volatile compounds were identified (98 confirmed against authentic standards) in a set of 21 samples obtained from different homes and working places. This list contains more than 40 fragrances (including several potential allergens), solvents and intermediates in the production of polymeric materials, plasticizers and flame retardants.

Direct Detection of Lysozyme in Viscous Raw Hen Egg White Binding to Sodium Dodecyl Sulfonate by Reactive Wooden-tip Electrospray Ionization Mass Spectrometry

Direct characterization of native protein binding to ligands in raw biological samples is a challenging task, because the ligand solution might induce proteins to aggregation, flocculation and denaturation. In this work, we developed a reactive wooden-tip electrospray ionization mass spectrometry (ESI-MS) for formation and characterization of protein-ligand complexes upon rapid mixing in electrospray droplets. Raw viscous hen egg white (HEW) was directly loaded onto a wooden tip to induce spray ionization, and sodium dodecyl sulfonate (SDS) solution was directly loaded into the HEW spray by a pipette tip, and thus lysozyme-DS complexes were then formed in the electrospray droplets and were detected subsequently by mass spectrometry. The new approach was successfully applied to investigate interaction of SDS and native lysozyme in electrospray droplets of standard solution and raw egg white. Our results showed that wooden-tip ESI-MS is a promising method to form and characterize protein-ligand complexes.

Polyethylene Terephthalate Nanofiber Sheet as the Novel Extraction Medium for the Determination of Phthalates in Water Samples

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 (CO₂) 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.