Development of Quantitative Chemical Ionization Using Gas Chromatography/Mass Spectrometry and Gas Chromatography/Tandem Mass Spectrometry for Ambient Nitro- and Oxy-PAHs and Its Applications.

The concentration of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere has been continually monitored since their toxicity became known, whereas nitro-PAHs (NPAHs) and oxy-PAHs (OPAHs), which are derivatives of PAHs by primary emissions or secondary formations in the atmosphere, have gained attention more recently. In this study, a method for the quantification of 18 NPAH and OPAH congeners in the atmosphere based on combined applications of gas chromatography coupled with chemical ionization mass spectrometry is presented. A high sensitivity and selectivity for the quantification of individual NPAH and OPAH congeners without sample preparations from the extract of aerosol samples were achieved using negative chemical ionization (NCI/MS) or positive chemical ionization tandem mass spectrometry (PCI-MS/MS). This analytical method was validated and applied to the aerosol samples collected from three regions in Northeast Asia-namely, Noto, Seoul, and Ulaanbaatar-from 15 December 2020 to 17 January 2021. The ranges of the method detection limits (MDLs) of the NPAHs and OPAHs for the analytical method were from 0.272 to 3.494 pg/m3 and 0.977 to 13.345 pg/m3, respectively. Among the three regions, Ulaanbaatar had the highest total mean concentration of NPAHs and OPAHs at 313.803 ± 176.349 ng/m3. The contribution of individual NPAHs and OPAHs in the total concentration differed according to the regional emission characteristics. As a result of the aerosol samples when the developed method was applied, the concentrations of NPAHs and OPAHs were quantified in the ranges of 0.016~3.659 ng/m3 and 0.002~201.704 ng/m3, respectively. It was concluded that the method could be utilized for the quantification of NPAHs and OPAHs over a wide concentration range.

Particulate Nitrosamines and Nitramines in Seoul and Their Major Sources: Primary Emission versus Secondary Formation.

Seven nitrosamines and three nitramines in particulate matter with an aerodynamic diameter of less than or equal to 2.5 µm (PM2.5) collected in 2018 in Seoul, South Korea, were quantified. Annual mean concentrations of the sum of nitrosamines and nitramines were 9.81 ± 18.51 and 1.12 ± 0.70 ng/m3, respectively, and nitrosodi-methylamine (NDMA) and dimethyl-nitramine (DMN) comprised the largest portion of nitrosamines and nitramines, respectively. Statistical analyses such as non-parametric correlation analysis, positive matrix factorization, analysis of covariance, and orthogonal partial least squared discrimination analysis were carried out to identify contribution of the atmospheric reactions in producing NDMA and DMN. In addition, kinetic calculation using reaction information obtained from the previous chamber studies was performed to estimate concentrations of NDMA and DMN that might be produced from the atmospheric reactions. It was concluded that (1) the atmospheric reactions contributed to the concentrations of NDMA more than they did for those of DMN, (2) the contribution of atmospheric reactions to the concentrations of NDMA and DMN was significant due to high NO2 concentrations in winter, and (3) primary emissions predominantly affected the ambient concentrations of NDMA and DMN in spring, summer, and autumn.

Rapid Characterization and Discovery of Chemical Markers for Discrimination of Xanthii Fructus by Gas Chromatography Coupled to Mass Spectrometry.

Xanthii Fructus (XF) is known as a medicinal plant. It has been used as a traditional medicine because of its high biological efficacy. However, there have been few comprehensive studies on the specific chemical composition of the plant and consequently, the information is lacking for the mechanism of the natural product metabolites in humans. In this study, an efficient analytical method to characterize and discriminate two species of Xanthii Fructus (Xanthium canadense Mill. and Xanthium sibiricum Patrin ex Widder) was established. Volatile organic compounds (VOCs), polar metabolites, and fatty acids were classified by integrated sample preparation, which allowed a broad range for the detection of metabolites simultaneously. Gas chromatography-mass spectrometry (GC-MS) followed by a multivariate statistical analysis was employed to characterize the chemical compositions and subsequently to discriminate between the two species. The results demonstrate that the two species possess obviously diverse chemical characteristics of three different classifications, and discriminant analysis was successfully applied to a number of chemical markers that could be used for the discrimination of the two species. Additional quantitative results for the selected chemical markers consistently showed significant differences between the two species.

Polychlorinated dibenzo-p-dioxins and dibenzofurans levels in piglet liver with various diseases.

This study deals with the levels of toxic polychlorinated dibenzo-p-dioxin and furan congeners (PCDD/Fs) in the livers of piglets affected by infectious diseases using isotope dilution high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Seventeen toxic congeners in the liver samples infected with bacterial and viral diseases were compared. For porcine reproductive and respiratory syndrome virus (PRRSV) samples, the North American- and European-type PRRS diseases were observed. This study shows that there are significantly different levels of PCDD/Fs, present, which vary according to the types of diseases as evidenced by our analysis of the piglet liver samples.

Identification and Characterization of Diploid and Tetraploid in Platycodon grandiflorum.

Platycodon grandiflorum (PG), a species of herbaceous flowering perennial plant of the family Campanulaceae, has been used as a traditional oriental medicine for bronchitis, asthma, pulmonary tuberculosis, diabetes, hepatic fibrosis, bone disorders and many others similar diseases and as a food supplement. For the primary profiling of PG gas chromatography coupled with high resolution - time of flight mass spectrometry (GC/HR-TOF MS) was used as an analytical tool. A comparison of optimal extraction of metabolites was carried out with a number of solvents [hexane, methylene chloride, methanol, ethanol, methanol: ethanol (70:30, v:v)]. In extracts with methanol: ethanol (70:30 v:v) were detected higher amounts of metabolites than with other solvents. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) plots showed significant differences between the diploid and tetraploid metabolite profiles. Extracts of tetraploid showed higher amounts of amino acids, while extracts of diploid contained more organic acids and sugars. Graphical Abstract ᅟ.

Formation of dimethyldithioarsinic acid in a simulated landfill leachate in relation to hydrosulfide concentration.

Dimethyldithioarsinic acid (DMDTA(V)), present in such intense sources as municipal landfill leachate, has drawn a great deal of attention due to its abundant occurrence and different aspect of toxicity. The hydrosulfide (HS(-)) concentration in leachate was studied as a major variable affecting the formation of DMDTA(V). To this end, the HPLC-ICPMS system equipped with the reversed-phase C18 column was used to determine DMDTA(V). Simulated landfill leachates (SLLs) were prepared to cover a mature landfill condition with the addition of sodium sulfate and sulfide at varying concentrations in the presence of dimethylarsinic acid (DMA(V)). The concentration of sodium sulfide added in the SLLs generally exhibited a strong positive correlation with the concentration of DMDTA(V). As such, the formation of DMDTA(V) in the SLLs is demonstrated to be controlled by the interactive relationship between DMA(V) and the HS(-).

Quantitative analysis of heterocyclic amines in urine by liquid chromatography coupled with tandem mass spectrometry.

A sensitive, reproducible, and rapid analytical method for the analysis of trace-level heterocyclic amines (HCAs) that are expected to have high levels of human exposure was developed. Liquid-liquid extraction (LLE) with dichloromethane (DCM) followed by solid-phase extraction (SPE) was carried out. Liquid extraction with DCM under basic conditions was efficient in extracting HCAs from urine samples. For further purification, mixed mode cationic exchange (MCX) cartridges were applied to eliminate the remaining interferences after liquid extraction. Separation and quantification were performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) in selected reaction monitoring (SRM) mode. The overall recoveries ranged between 71.0% and 113.6% with relative standard deviations (RSDs) of 5.1% to 14.7% for the entire procedure. The limits of detection (LODs) and limits of quantification (LOQs) of the proposed analytical method were in the ranges of 0.04 to 0.10 ng/ml and 0.15 to 0.36 ng/ml, respectively. This method was applied to the analysis of monitoring in urine samples for Korean school children, and the results demonstrated that the method can be used for the trace determination of HCAs in urine samples.

Inhibitory Effects of Ginsenoside Metabolites, Compound K and Protopanaxatriol, on GABAC Receptor-Mediated Ion Currents.

Ginsenosides, one of the active ingredients of Panax ginseng, show various pharmacological and physiological effects, and they are converted into compound K (CK) or protopanaxatriol (M4) by intestinal microorganisms. CK is a metabolite derived from protopanaxadiol (PD) ginsenosides, whereas M4 is a metabolite derived from protopanaxatriol (PT) ginsenosides. The γ-aminobutyric acid receptorC (GABAC) is primarily expressed in retinal bipolar cells and several regions of the brain. However, little is known of the effects of ginsenoside metabolites on GABAC receptor channel activity. In the present study, we examined the effects of CK and M4 on the activity of human recombinant GABAC receptor (ρ1) channels expressed in Xenopus oocytes by using a 2-electrode voltage clamp technique. In oocytes expressing GABAC receptor cRNA, we found that CK or M4 alone had no effect in oocytes. However, co-application of either CK or M4 with GABA inhibited the GABA-induced inward peak current (IGABA ). Interestingly, pre-application of M4 inhibited IGABA more potently than CK in a dose-dependent and reversible manner. The half-inhibitory concentration (IC50) values of CK and M4 were 52.1±2.3 and 45.7±3.9 µM, respectively. Inhibition of IGABA by CK and M4 was voltage-independent and non-competitive. This study implies that ginsenoside metabolites may regulate GABAC receptor channel activity in the brain, including in the eyes.

Developing an Improved Strategy for the Analysis of Polychlorinated Dibenzo-p-Dioxins/Furans and Dioxin-like Polychlorinated Biphenyls in Contaminated Soils Using a Combination of a One-Step Cleanup Method and Gas Chromatography with Triple Quadrupole Mass Spectrometry.

Soils contaminated with polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and dioxin-like (dl) polychlorinated biphenyls (PCBs), known as persistent organic pollutants (POPs), have garnered global attention because of their toxicity and persistence in the environment. The standard method for target analytes has been used; however, it is an obstacle in large-scale sample analysis due to the comprehensive sample preparation and high-cost instrumental analysis. Thus, analytical development of inexpensive methods with lower barriers to determine PCDDs/Fs and dl-PCBs in soil is needed. In this study, a one-step cleanup method was developed and validated by combining a multilayer silica gel column and Florisil micro-column followed by gas chromatography with triple quadrupole mass spectrometry (GC-QqQ-MS/MS). To optimize the separation and quantification of 17 PCDDs/Fs and 12 dl-PCBs in soils, the sample cleanup and instrumental conditions were investigated. For quantification method validation, spiking experiments were conducted to determine the linearity of the calibration, recovery, and method detection limit of PCDDs/Fs and dl-PCBs using isotopic dilution GC-QqQ-MS/MS. The applicability of the simultaneous determination of PCDDs/Fs and dl-PCBs was confirmed by the recovery of native target congeners and labeled surrogate congeners spiked into the quality-control and actual soil samples. The results were in good agreement with the requirements imposed by standard methods. The findings in this work demonstrated the high accessibility of the sample cleanup and analysis methods for the efficient determination of PCDDs/Fs and dl-PCBs in contaminated soils.

Significant diethyl phthalate (DEP) degradation by combined advanced oxidation process in aqueous solution.

Ultrasound (US) combined with ultraviolet (UV) irradiation and a titanium dioxide (TiO(2)) catalyst was used to effectively remove diethyl phthalate (DEP) from aqueous solutions. Single (sonolysis, photolysis, photocatalysis) and combined (sonophotolysis, sonophotocatalysis) processes were performed to confirm the synergistic effects and DEP degradation mechanism. Using only US, the optimum frequency for DEP degradation was 283 kHz. At this frequency a high rate of hydrogen peroxide (H(2)O(2)) formation was observed of approximately 0.32 mM min(-1). The pseudo-first order degradation rate constants were 10(-2)-10(-4) min(-1) depending on the process. Significant degradation and mineralization (TOC) of DEP were observed with the sonophotolytic and sonophotocatalytic processes. Moreover, synergistic effects of 1.29 and 1.95 were exhibited at the sonophotocatalytic and sonophotolytic DEP degradation, respectively. Furthermore, additional advantageous reactions may occur in the heterogeneous sonophotocatalytic process due to interactions between US, UV, and the photocatalyst.

Gas chromatography-triple quadrupole mass spectrometry as a cost-effective method for the determination of polychlorinated dibenzo-p-dioxins and furans in contaminated soils.

The aim of this study was to evaluate the performance of gas chromatography (GC)-triple quadrupole mass spectrometry (QqQ, MS/MS) as an alternative to the standard GC-high resolution mass spectrometry (GC-HR/MS) for soils contaminated with polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). GC-QqQ (MS/MS) using a dynamic multiple reaction monitoring (dMRM) mode was optimized for the quantitative analysis of 17 PCDD/Fs. A comparative study between GC-QqQ (MS/MS) and GC-HR/MS was carried out to validate the results of actual field soil samples. Although GC-HR/MS has excellent sensitivity and selectivity, the validation parameters obtained by GC-QqQ (MS/MS) also met the recommended criteria of the standard method. The results for total and I-TEQ (international toxic equivalent) value of the PCDD/F concentrations of over 86.0 pg/g and 4.3 pg I-TEQ/g, respectively, in actual field soil samples showed good agreement between the two methods, falling within ±25% relative difference. In consideration of the remediation goal (100 pg I-TEQ/g), GC-QqQ (MS/MS) can be an alternative cost-effective method for use in soil remediation research.

Characterization of dandelion species using 1H NMR- and GC-MS-based metabolite profiling.

Taraxacum, known as dandelion, is a large genus of plants in the family Asteraceae. Pharmacological studies have shown that these plants display a wide variety of medicinal properties because Taraxacum extracts contain many pharmacologically active metabolites that display anti-inflammatory, antinociceptive, antioxidant, and anticancer activity. Each plant species displays several different natural constituents, the majority of which have not been studied as no global metabolite screen of the diverse Taraxacum species has been performed. In this study, we investigated the metabolite difference in three species of Taraxacum (T. coreanum, T. officinale, and T. platycarpum) by (1)H NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS) coupled with multivariate statistical analyses. The aim of this study was to identify the different chemical compositions of the polar and nonpolar extracts in these species. A partial least-squares discriminant analysis showed a significantly higher separation among nonpolar extracts (mainly fatty acids and sterols) compared to polar extracts (mainly amino acids, organic acids, and sugars) between these species. A one-way ANOVA was performed to statistically certify the metabolite differences of these nonpolar extracts. Taken together, these data suggest that a metabolomic approach using combined (1)H NMR and GC-MS analysis is an effective analytical method to differentiate biochemical compositions among different species in plants.

Trace Level Determination of Saccharides in Pristine Marine Aerosols by Gas Chromatography-Tandem Mass Spectrometry.

The quantification and identification of saccharides in pristine marine aerosols can provide useful information for determining the contributions of anthropogenic and natural sources of the aerosol. However, individual saccharide compounds in pristine marine aerosols that exist in trace amounts are difficult to analyze due to their low concentrations. Thus, in this study, we applied gas chromatography-tandem mass spectrometry (GC-MS/MS) in multiple reaction monitoring (MRM) mode to analyze the particulate matter with an aerodynamic diameter equal or less than 2.5 µm (PM2.5) samples, and the results were compared with those of conventional GC-MS. To investigate the chemical properties of pristine marine aerosols, 12 PM2.5 samples were collected while aboard Araon, an ice-breaking research vessel (IBRV), as it sailed from Incheon, South Korea to Antarctica. The method detection limits of GC-MS/MS for 10 saccharides were 2-22-fold lower than those of GC-MS. Consequently, the advantages of GC-MS/MS include (1) more distinct peak separations, enabling the accurate identification of the target saccharides and (2) the quantification of all individual saccharide compounds with concentrations outside the quantifiable range of GC-MS. Accordingly, the time resolution for sampling saccharides in pristine marine aerosols can be improved with GC-MS/MS.

1H NMR-based metabolomic study on resistance to diet-induced obesity in AHNAK knock-out mice.

AHNAK is a giant protein of approximately 700 kDa identified in human neuroblastomas and skin epithelial cells. Recently, we found that AHNAK knock-out (AHNAK(-/-)) mice have a strong resistance to high-fat diet-induced obesity. In this study, we applied (1)H NMR-based metabolomics with multivariate statistical analysis to compare the altered metabolic patterns detected in urine from high-fat diet (HFD) fed wild-type and AHNAK(-/-) mice and investigate the mechanisms underlying the resistance to high-fat diet-induced obesity in AHNAK(-/-) mice. In global profiling, principal components analysis showed a clear separation between the chow diet and HFD groups; wild-type and AHNAK(-/-) mice were more distinctly separated in the HFD group compared to the chow diet group. Based on target profiling, the urinary metabolites of HFD-fed AHNAK(-/-) mice gave higher levels of methionine, putrescine, tartrate, urocanate, sucrose, glucose, threonine, and 3-hydroxyisovalerate. Furthermore, two-way ANOVAs indicated that diet type, genetic type, and their interaction (gene × diet) affect the metabolite changes differently. Most metabolites were affected by diet type, and putrescine, threonine, urocanate, and tartrate were also affected by genetic type. In addition, cis-aconitate, succinate, glycine, histidine, methylamine (MA), phenylacetylglycine (PAG), methionine, putrescine, uroconate, and tartrate showed interaction effects. Through the pattern changes in urinary metabolites of HFD-fed AHNAK(-/-) mice, our data suggest that the strong resistance to HFD-induced obesity in AHNAK(-/-) mice comes from perturbations of amino acids, such as methionine, putrescine, threonine, and histidine, which are related to fat metabolism. The changes in metabolites affected by microflora such as PAG and MA were also observed. In addition, resistance to obesity in HFD-fed AHNAK(-/-) mice was not related to an activated tricarboxylic acid cycle. These findings demonstrate that (1)H NMR-based metabolic profiling of urine is suitable for elucidating possible biological pathways perturbed by functional loss of AHNAK on HFD feeding and could elucidate the mechanism underlying the resistance to high-fat diet-induced obesity in AHNAK(-/-) mice.

Determination of elemental compositions by gas chromatography/time-of-flight mass spectrometry using chemical and electron ionization.

Many metabolomic applications use gas chromatography/mass spectrometry (GC/MS) under standard 70 eV electron ionization (EI) parameters. However, the abundance of molecular ions is often extremely low, impeding the calculation of elemental compositions for the identification of unknown compounds. On changing the beam-steering voltage of the ion source, the relative abundances of molecular ions at 70 eV EI were increased up to ten-fold for alkanes, fatty acid methyl esters and trimethylsilylated metabolites, concomitant with 2-fold absolute increases in ion intensities. We have compared the abundance, mass accuracy and isotope ratio accuracy of molecular species in EI with those in chemical ionization (CI) with methane as reagent gas under high-mass tuning. Thirty-three peaks of a diverse set of trimethylsilylated metabolites were analyzed in triplicate, resulting in 342 ion species ([M+H](+), [M-CH(3)](+) for CI and [M](+.), [M-CH(3)](+.) for EI). On average, CI yielded 8-fold more intense molecular species than EI. Using internal recalibration, average mass errors of 1.8 +/- 1.6 mm/z units and isotope ratio errors of 2.3 +/- 2.0% (A+1/A ratio) and 1.7 +/- 1.8% (A+2/A ratio) were obtained. When constraining lists of calculated elemental compositions by chemical and heuristic rules using the Seven Golden Rules algorithm and PubChem queries, the correct formula was retrieved as top hit in 60% of the cases and within the top-3 hits in 80% of the cases.

Determination of atmospheric amines at Seoul, South Korea via gas chromatography/tandem mass spectrometry.

Due to their important roles in salt-producing acid-base reactions, new particle formation (NPF), and as precursors in secondary organic aerosol (SOA) producing reactions, the atmospheric concentrations of particulate volatile amines (dimethylamine (DMA), ethylamine, diethylamine (DEA), propylamine, and butylamine) at Seoul were analyzed and evaluated. To quantify the presence of volatile amines in particulate matter with aerodynamic diameters less than or equal to a nominal 2.5 µm (PM2.5), an efficient and rapid analytical method based on in-matrix ethyl chloroformate (ECF) derivatization followed by headspace solid-phase microextraction (HS-SPME) was developed and validated using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) in the multiple reaction monitoring (MRM) mode. The annual mean concentration of the total 5 target amines was 5.56±2.76 ng/m3 and the seasonal difference was small. The concentrations of particulate amines measured in this study were lower than those observed in Zongludak, Turkey, Nanjing, China, and Jeju, Korea but slightly higher than that reported in Kobe, Japan. The concentrations of the nitrosamines (nitrosodimethylamine (NDMA) and nitrosodiethylamine (NDEA)), and of the nitramines (dimethylnitramine (DMN) and diethylnitramine (DEN)) measured along with those of the target amines were used in a simple linear regression analysis. It indicates the contribution of DMA to the formation of NDMA in all seasons (except the fall) and DEA to the formation of NDEA in the summer, while DMA and DEA did not significantly contribute to the formation of nitramines.

Development of non-equilibrium rapid replacement aptamer assay for ultra-fast detection of phthalic acid esters.

In this paper, we developed a non-equilibrium rapid replacement aptamer (NERRA) assay that performed ultra-fast (in 30 s) quantitative detection of phthalic acid esters (PAEs) without waiting for the reaction to reach equilibrium. NERRA assay employed fluorescence PoPo3 dye intercalated in an ssDNA aptamer to selectively detect and quantify the PAEs in water. As the intercalated dye was replaced by the PAEs and quenched in the water, the rate of fluorescence change became proportional to PAEs concentration. The sensitivity of NERRA assay was first evaluated with a commercial spectrofluorometer. The selectivity for PAE mixture, individual PAEs, and non-phthalate compounds were also investigated. NERRA assay was also able to quantitatively detect the PAEs in a common plastic product (picnic mat), and the results were compared with those of gas chromatography mass spectrometry. Finally, a custom analyzer (8.5 cm × 8.5 cm × 16.5 cm) was built to demonstrate the portability of the NERRA assay. Using a commercial spectrofluorometer, NERRA assay was able to quantitatively detect a PAE mixture in 30 min with an LOQ of 0.1 µg/L. Using the portable custom analyzer, the detection time was shortened to 30 s with a tradeoff in the LOQ (1 µg/L). In both cases, the LOQs remain within the environmentally relevant PAE concentrations of 0.1-1472 µg/L.

Discrimination of Platycodon grandiflorum and Codonopsis lanceolata using gas chromatography-mass spectrometry-based metabolomics approach.

Species of herbaceous flowering perennial plant of the family Campanulaceae such as Platycodon grandiflorum (P. grandiflorum) and Codonopsis lanceolata (C. lanceolata) widely used in traditional medicine to treat different diseases. In spite of different medicinal results after consumption of the plants, it is hard to distinguish between two of them, because of their similar morphological characteristics. In this study, a gas chromatography-mass spectrometry (GC-MS) - based metabolite profiling approach was performed and examined to discriminate tuberous roots of P. grandiflorum and C. lanceolate for medicinal purposes. Two basic approaches for sample preparation, headspace solid-phase microextraction (HS-SPME) and solvent extraction were adopted. Multivariate statistical techniques, such as orthogonal partial least-squares discriminant analysis (OPLS-DA) plots showed significant differences between P. grandiflorum and C. lanceolata for polar primary and volatile organic metabolites. A number of potential candidates were suggested as the chemomarkers for discrimination of two plants.

Inter-Laboratory Validation of Method to Determine Residual Enrofloxacin in Chicken Meat.

An inter-laboratory study was performed to evaluate the performance of a method developed for the quantification of enrofloxacin in chicken meat. Liquid-liquid extraction combined with a clean-up procedure based on solid-phase extraction followed by a liquid chromatography-tandem mass spectrometric method was used by three individual laboratories. All the investigated results of calibration curves and limits of quantification were within the acceptable range for regulatory testing of enrofloxacin. The three laboratories received blind a certified reference material to analyze in triplicate and assess using statistical analysis. From the results, no statistical differences were found between the laboratories in the precision of the method. Additionally, all the results of the z-score, which is an indication of fixed interval bias criteria for accuracy from the laboratories, fell within the allowable limits (±2σ). Based on this proficiency testing by inter-laboratory comparisons, the analytical method including the sample preparation step was proven to be applicable.

Development and Validation of Gas Chromatography-Triple Quadrupole Mass Spectrometric Method for Quantitative Determination of Regulated Plasticizers in Medical Infusion Sets.

A method for the quantitative determination of dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), bis(2-ethylhexyl) adipate (DEHA), bis(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), dioctyl terephthalate (DOTP), diisononyl phthalate (DINP), and diisodecyl phthalate (DIDP) in medical infusion sets was developed and validated using gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) in the multiple reaction monitoring (MRM) mode. Solvent extraction with polymer dissolution for sample preparation was employed prior to GC-MS/MS analysis. Average recoveries of the eight target analytes are typically in the range of 91.8-122% with the relative standard deviations of 1.8-17.8%. The limits of quantification (LOQs) of the analytical method were in the ranges of 54.1 to 76.3 ng/g. Analysis using GC-MS/MS provided reliable performance, as well as higher sensitivity and selectivity than GC-MS analysis, especially for the presence of minority plasticizers at different concentrations.