Use of high-resolution mass spectrometry to identify precursors and biodegradation products of perfluorinated and polyfluorinated compounds in end-user products.

Structural identification of perfluoroalkyl and polyfluoroalkyl substances found in end-user products and their biodegradation products was performed using ultra-high resolution mass spectrometry. Little attention has so far been paid to the environmental burden of perfluorooctane sulfonate and perfluorooctanoic acid from compounds with a molar mass of ~2,000. Analysis of end-user waterproofing and stain repellent products revealed the presence of numerous ions with molar masses ranging from 1,000 to 2,000 and complex mass spectra. Ultra-high resolution mass spectrometry determined the accurate mass of the observed ions, allowing the cleavage position and fragment structure to be determined. The precursor structures were determined based on reconstitution of the retrieved fragments. Products of fluorochemical manufacturers before voluntary regulation comprised compounds with plural perfluorooctyl chains. In the current product lines, compounds comprising perfluorobutyl chains were detected. Biodegradation tests using activated sludge revealed that biodegradation products consistent with those reported previously were generated even from complex end-user products. For example, the biodegradation test revealed the formation of N-ethyl perfluorooctane sulfonamido acetic acid and various fluorotelomer acids in the samples. The results of the present study suggest that the environmental burden of these compounds should be reevaluated.

Two-dimensional mapping using different chromatographic separations coupled with mass spectrometry for the analysis of ginsenosides in Panax ginseng root and callus.

Two-dimensional (2D) mapping using different chromatographic separations coupled with mass spectrometry is a rapid and simple method for the analysis of a mixture using conventional liquid chromatography mass spectrometry. The 2D map could be created from two different chromatograms obtained with the same detector and different columns or separation methods. In this study, 2D mapping was applied to the analysis of components contained in Panax ginseng, and was evaluated in terms of its effectiveness in the separation of these components. The several glycosides included in Panax ginseng could not be sufficiently separated by one-dimensional chromatography with a reverse phase or a hydrophilic interaction chromatography (HILIC) column, but the components of Panax ginseng could be separated and visualized as a component pattern by 2D mapping. We showed that the components contained in the calli and their quantities were altered by the culture conditions in which the calli were grown by 2D mapping. 2D mapping is expected to be a useful method for visualizing complex component patterns found in glycosides and unknown compounds in foods.

Platinum vapor deposition surface-assisted laser desorption/ionization for imaging mass spectrometry of small molecules.

RATIONALE: Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) allows for the simultaneous detection and imaging of several molecules in a sample. However, when using an organic matrix in the MALDI-IMS of small molecules, inhomogeneous matrix crystallization may yield poorly reproducible peaks in the mass spectra. We describe a solvent-free approach that employs a homogeneously deposited metal nanoparticle layer (or film) for small-molecule detection. METHODS: Platinum vapor deposition surface-assisted laser desorption/ionization imaging mass spectrometry (Pt vapor deposition SALDI-IMS) of small molecules was performed as a solvent-free and organic-matrix-free method. A commercially available magnetron sputtering device was used for Pt deposition. Vapor deposition of Pt produced a homogenous layer of nanoparticles over the surface of the target imaging sample. RESULTS: The effectiveness of Pt vapor deposition SALDI-IMS was demonstrated for the direct detection of small analytes of inkjet ink on printed paper as well as for various other analytes (saccharides, pigments, and drugs) separated by thin-layer chromatography (TLC), without the need for extraction or concentration processes. The advantage of choosing Pt instead of Au in SALDI-IMS was also shown. CONCLUSIONS: A solvent-free approach involving the direct deposition of Pt on samples (SALDI-IMS) is effective for the analysis of inkjet-printed papers and various analytes separated by TLC. This method would be useful in imaging analyses of various insulating materials such as polymers and biological materials.

Evaluation of river pollution of neonicotinoids in Osaka City (Japan) by LC/MS with dopant-assisted photoionisation.

An atmospheric pressure photoionisation (APPI) source for liquid chromatography/mass spectrometry (LC/MS) was applied to determine neonicotinoid pesticides in the aquatic environment. Dopant-assisted APPI was very effective in the ionisation of neonicotinoids. Neonicotinoids generated protonated molecules in APPI with high sensitivity, while adduct ions, such as sodiated molecules, were predominantly generated in conventional electrospray ionisation. The ionisation of neonicotinoids was confirmed by ultra-high-resolution MS. An analytical method coupled with solid phase extraction was developed for acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, and thiamethoxam. Method detection limits were 0.47 to 2.1 ng L(-1) for six neonicotinoids. Dinotefuran was the most frequent and highest among the neonicotinoids examined in the aquatic environment in Osaka, Japan. The maximum concentration of dinotefuran was 220 ng L(-1). Given the toxicity of neonicotinoids for aquatic creatures, the concentrations observed here were substantially low. The change in concentrations was temporally coincident with the period of the neonicotinoid application. Although rapid photodegradation and some degradation products have been elucidated, the degradation products in the aquatic environment were not identified in the present study.

Correlations between Chemical Compositions and Retention Times of Methacrylate Random Copolymers Using LC-ESI-MS.

Correlations between chemical compositions and chromatographic retention times (Rt) of methacrylate random copolymers were studied by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). Twenty-six different polymers including homopolymers of poly(methyl methacrylate) (PMMA), poly(tert-butyl methacrylate) (PTBMA) and poly(2-hydroxyethyl methacrylate) (PHEMA), and their random copolymers of P(MMA-TBMA) and P(MMA-HEMA) with known chemical compositions were studied. The results indicate that there is close correlations between the chemical compositions of the random copolymers and their Rt of the C8 column in the mass spectral ranges of m/z 1,800-2,000. The LC-ESI-MS analysis showed molecular weights of the copolymers distribute in the mass range of ca. 500-20,000, and the structures of polymer terminals and their monomer units can be identified.