Sliding Windows in Ion Mobility (SWIM): A New Approach to Increase the Resolving Power in Trapped Ion Mobility-Mass Spectrometry Hyphenated with Chromatography

Over the past decade, the separation efficiency achieved by linear IMS instruments has increased substantially, with state-of-the-art IM technologies, such as the trapped ion mobility (TIMS), the cyclic traveling wave ion mobility (cTWIMS), and the structure for lossless ion manipulation (SLIM) platforms commonly demonstrating resolving powers in excess of 200. However, for complex sample analysis that require front end separation, the achievement of such high resolving power in TIMS is significantly hampered, since the ion mobility range must be broad enough to analyze all the classes of compounds of interest, whereas the IM analysis time must be short enough to cope with the time scale of the preseparation technique employed. In this paper, we introduce the concept of sliding windows in ion mobility (SWIM) for chromatography hyphenated TIMS applications that bypasses the need to use a wide and fixed IM range by using instead narrow and mobile ion mobility windows that adapt to the analytes’ ion mobility during chromatographic separation. GC-TIMS-MS analysis of a mixture of 174 standards from several halogenated persistent organic pollutant (POP) classes, including chlorinated and brominated dioxins, biphenyls, and PBDEs, demonstrated that the average IM resolving power could be increased up to 40% when the SWIM mode was used, thereby greatly increasing the method selectivity for the analysis of complex samples

Sliding Windows in Ion Mobility (SWIM): A New Approach to Increase the Resolving Power in Trapped Ion Mobility-Mass Spectrometry Hyphenated with Chromatography

Over the past decade, the separation efficiency achieved by linear IMS instruments has increased substantially, with state-of-the-art IM technologies, such as the trapped ion mobility (TIMS), the cyclic traveling wave ion mobility (cTWIMS), and the structure for lossless ion manipulation (SLIM) platforms commonly demonstrating resolving powers in excess of 200. However, for complex sample analysis that require front end separation, the achievement of such high resolving power in TIMS is significantly hampered, since the ion mobility range must be broad enough to analyze all the classes of compounds of interest, whereas the IM analysis time must be short enough to cope with the time scale of the preseparation technique employed. In this paper, we introduce the concept of sliding windows in ion mobility (SWIM) for chromatography hyphenated TIMS applications that bypasses the need to use a wide and fixed IM range by using instead narrow and mobile ion mobility windows that adapt to the analytes’ ion mobility during chromatographic separation. GC-TIMS-MS analysis of a mixture of 174 standards from several halogenated persistent organic pollutant (POP) classes, including chlorinated and brominated dioxins, biphenyls, and PBDEs, demonstrated that the average IM resolving power could be increased up to 40% when the SWIM mode was used, thereby greatly increasing the method selectivity for the analysis of complex samples

Sliding Windows in Ion Mobility (SWIM): A New Approach to Increase the Resolving Power in Trapped Ion Mobility-Mass Spectrometry Hyphenated with Chromatography

Over the past decade, the separation efficiency achieved by linear IMS instruments has increased substantially, with state-of-the-art IM technologies, such as the trapped ion mobility (TIMS), the cyclic traveling wave ion mobility (cTWIMS), and the structure for lossless ion manipulation (SLIM) platforms commonly demonstrating resolving powers in excess of 200. However, for complex sample analysis that require front end separation, the achievement of such high resolving power in TIMS is significantly hampered, since the ion mobility range must be broad enough to analyze all the classes of compounds of interest, whereas the IM analysis time must be short enough to cope with the time scale of the preseparation technique employed. In this paper, we introduce the concept of sliding windows in ion mobility (SWIM) for chromatography hyphenated TIMS applications that bypasses the need to use a wide and fixed IM range by using instead narrow and mobile ion mobility windows that adapt to the analytes’ ion mobility during chromatographic separation. GC-TIMS-MS analysis of a mixture of 174 standards from several halogenated persistent organic pollutant (POP) classes, including chlorinated and brominated dioxins, biphenyls, and PBDEs, demonstrated that the average IM resolving power could be increased up to 40% when the SWIM mode was used, thereby greatly increasing the method selectivity for the analysis of complex samples

Chemicals and materials.

Procellariiform seabirds are known to have high rates of plastic ingestion. We investigated the bioaccessibility of plastic-associated chemicals [plastic additives and sorbed persistent organic pollutants (POPs)] leached from plastic over time using an in vitro Procellariiform gastric model. High-density polyethylene (HDPE) and polyvinyl chloride (PVC), commonly ingested by Procellariiform seabirds, were manufactured with one additive [decabrominated diphenyl ether (PBDE-209) or bisphenol S (BPS)]. HDPE and PVC added with PBDE-209 were additionally incubated in salt water with 2,4,4’-trichloro-1,1’-biphenyl (PCB-28) and 2,2’,3,4,4’,5’-hexachlorobiphenyl (PCB-138) to simulate sorption of POPs on plastic in the marine environment. Our results indicate that the type of plastic (nature of polymer and additive), presence of food (i.e., lipids and proteins) and gastric secretions (i.e., pepsin) influence the leaching of chemicals in a seabird. In addition, 100% of the sorbed POPs were leached from the plastic within 100 hours, while only 2–5% of the additives were leached from the matrix within 100 hours, suggesting that the remaining 95% of the additives could continue to be leached. Overall, our study illustrates how plastic type, diet and plastic retention time can influence a Procellariform’s exposure risk to plastic-associated chemicals.</div

Fig 2 -

Percentage of plastic additives (A) and PCBs (B) released from HDPE and PVC in different solutions after 20h. HDPE and PVC pieces with 1% PBDE-209 + PCB-28 and -138 or HDPE and PVC pieces with 1% BPS were leached in hexane, salmon oil, calanus oil, an aqueous digestive solution made of albumin, pepsin, HCl and water (“Acid/pep/alb solution”), an acidic pepsin solution (“Acid/pep solution”), acidic water and water for 20h at 38°C (800 rpm; n = 3). Panel A) the concentrations of additives (PBDE-209 in black and BPS in white) leached from HDPE and PVC. Panel B) the concentrations of PCBs (PCB-28 in black and PCB-138 in white) leached from HDPE and PVC. Values with different uppercase letters (A, B, C, D, E, F for PBDE-209 or PCB-28) or lowercase letters (a, b, c, d, e, f for BPS or PCB-138) show significant differences between treatments (p-val < 0.05). Asterisk (*) (PBDE-209 or PCB-28) and pound sign (#) (BPS or PCB-138) depict significant differences between polymers for each chemical and treatment (p-val < 0.05). Error bars represent standard deviation, n = 3.</p

Experimental design.

Two HDPE and PVC plastic plates were supplemented with decabrominated diphenyl ether (PBDE-209) or bisphenol S (BPS) at a concentration of 1% (w/w). Plastic plates were cut in 5 mm x 5 mm x 1 mm square pieces. A total of 300 pieces of each polymer with 1% PBDE-209 were incubated in 100 ml of salt water under agitation (150 rpm; RT; in the dark) for three weeks with polychlorinated biphenyl -28 and -138 (PCB-28 and PCB-138). To study the influence of lipids, enzymes, proteins and acidity, ten plastic pieces (HDPE or PVC) containing either 1% BPS or 1% PBDE-209 + PCBs-28 and -138 were exposed to either (i) salmon (ii) calanus oil, (iii) an acidic albumin-pepsin solution (iv) an acidic pepsin solution or (v) acidic water for 20 hours at 38°C. Hexane and milli-Q water were used as controls. To study the influence of contact time on the release of chemicals, 10 plastic pieces containing either 1% BPS or 1% PBDE-209 + PCB-28 and -138 were incubated in the Procellariiform gastric model (PGM), containing an acidic albumin-pepsin solution mixed either with salmon oil or calanus oil for 100 hours. This gastric solution was replaced every 20 hours. Controls of water mixed with hexane were run in parallel.</p

Example of wax ester found in the oil of calanus finmarchicus.

Example of wax ester found in the oil of calanus finmarchicus.</p

Comprehensive overview of the influence of the polymer type and digestive conditions on the leaching of PBDE-209, PCBs and BPS.

Comprehensive overview of the influence of the polymer type and digestive conditions on the leaching of PBDE-209, PCBs and BPS.</p

Concentration of BPS released from HDPE (1) and PVC (2) in each phase of the salmon or calanus gastric fluid over time.

Concentration of BPS released from HDPE (1) and PVC (2) in each phase of the salmon or calanus gastric fluid over time.</p

Statistical analysis.

Procellariiform seabirds are known to have high rates of plastic ingestion. We investigated the bioaccessibility of plastic-associated chemicals [plastic additives and sorbed persistent organic pollutants (POPs)] leached from plastic over time using an in vitro Procellariiform gastric model. High-density polyethylene (HDPE) and polyvinyl chloride (PVC), commonly ingested by Procellariiform seabirds, were manufactured with one additive [decabrominated diphenyl ether (PBDE-209) or bisphenol S (BPS)]. HDPE and PVC added with PBDE-209 were additionally incubated in salt water with 2,4,4’-trichloro-1,1’-biphenyl (PCB-28) and 2,2’,3,4,4’,5’-hexachlorobiphenyl (PCB-138) to simulate sorption of POPs on plastic in the marine environment. Our results indicate that the type of plastic (nature of polymer and additive), presence of food (i.e., lipids and proteins) and gastric secretions (i.e., pepsin) influence the leaching of chemicals in a seabird. In addition, 100% of the sorbed POPs were leached from the plastic within 100 hours, while only 2–5% of the additives were leached from the matrix within 100 hours, suggesting that the remaining 95% of the additives could continue to be leached. Overall, our study illustrates how plastic type, diet and plastic retention time can influence a Procellariform’s exposure risk to plastic-associated chemicals.</div