Feasibility of a Selective Epoxidation Technique for Use in Quantification of Peracetic Acid in Air Samples Collected on Sorbent Tubes.

Peracetic acid is a disinfection agent used in medical and food processing facilities, and occupational exposures have been documented. To facilitate characterization of daily occupational exposures, the current work describes the development of a personal sampling technique to quantify the peracetic acid concentration in air samples. Peracetic acid atmospheres were generated in 100 L Teflon chambers, and samples were collected on 350 mg XAD-7 solid sorbent tubes for 4 h at a flow rate of 250 mL/min using a personal sampling pump. Indirect measurement of peracetic acid was achieved by desorption from the sorbent and subsequent treatment with cyclohexene to initiate an epoxidation reaction, formally known as the Prilezhaev reaction. The epoxidation product, cyclohexene oxide, was quantified by gas chromatography-mass spectrometry. The reaction enabled quantification of peracetic acid with high specificity over the common co-contaminants hydrogen peroxide and acetic acid, which were introduced in 10-fold and 100-fold excess to challenge the reaction. The technique also demonstrated an overall estimate of bias and precision of 11 and 8%, respectively, and a limit of detection of 60 ppbv was estimated. Preliminary storage experiments indicate that unreacted peracetic acid is stable on the sorbent tubes for 72 h when stored at -20 °C following collection. Overall, the specificity of the reaction and capability to sample for longer time periods than current methods, in addition to the use of safer personal sampling materials, demonstrate the utility of this technique for peracetic acid measurement in air.

Mass SARS-CoV-2 Testing in a Dormitory-Style Correctional Facility in Arkansas.

Objectives. To assess SARS-CoV-2 transmission within a correctional facility and recommend mitigation strategies.Methods. From April 29 to May 15, 2020, we established the point prevalence of COVID-19 among incarcerated persons and staff within a correctional facility in Arkansas. Participants provided respiratory specimens for SARS-CoV-2 testing and completed questionnaires on symptoms and factors associated with transmission.Results. Of 1647 incarcerated persons and 128 staff tested, 30.5% of incarcerated persons (range by housing unit = 0.0%-58.2%) and 2.3% of staff tested positive for SARS-CoV-2. Among those who tested positive and responded to symptom questions (431 incarcerated persons, 3 staff), 81.2% and 33.3% were asymptomatic, respectively. Most incarcerated persons (58.0%) reported wearing cloth face coverings 8 hours or less per day, and 63.3% reported close contact with someone other than their bunkmate.Conclusions. If testing remained limited to symptomatic individuals, fewer cases would have been detected or detection would have been delayed, allowing transmission to continue. Rapid implementation of mass testing and strict enforcement of infection prevention and control measures may be needed to mitigate spread of SARS-CoV-2 in this setting.

Large-Format Additive Manufacturing and Machining Using High-Melt-Temperature Polymers. Part I: Real-Time Particulate and Gas-Phase Emissions.

The literature on emissions during material extrusion additive manufacturing with 3-D printers is expanding; however, there is a paucity of data for large-format additive manufacturing (LFAM) machines that can extrude high-melt-temperature polymers. Emissions from two LFAM machines were monitored during extrusion of six polymers: acrylonitrile butadiene styrene (ABS), polycarbonate (PC), high-melt-temperature polysulfone (PSU), poly(ether sulfone) (PESU), polyphenylene sulfide (PPS), and Ultem (poly(ether imide)). Particle number, total volatile organic compound (TVOC), carbon monoxide (CO), and carbon dioxide (CO2) concentrations were monitored in real-time. Particle emission rate values (no./min) were as follows: ABS (1.7 × 1011 to 7.7 × 1013), PC (5.2 × 1011 to 3.6 × 1013), Ultem (5.7 × 1012 to 3.1 × 1013), PPS (4.6 × 1011 to 6.2 × 1012), PSU (1.5 × 1012 to 3.4 × 1013), and PESU (2.0 to 5.0 × 1013). For print jobs where the mass of extruded polymer was known, particle yield values (g-1 extruded) were as follows: ABS (4.5 × 108 to 2.9 × 1011), PC (1.0 × 109 to 1.7 × 1011), PSU (5.1 × 109 to 1.2 × 1011), and PESU (0.8 × 1011 to 1.7 × 1011). TVOC emission yields ranged from 0.005 mg/g extruded (PESU) to 0.7 mg/g extruded (ABS). The use of wall-mounted exhaust ventilation fans was insufficient to completely remove airborne particulate and TVOC from the print room. Real-time CO monitoring was not a useful marker of particulate and TVOC emission profiles for Ultem, PPS, or PSU. Average CO2 and particle concentrations were moderately correlated (r s = 0.76) for PC polymer. Extrusion of ABS, PC, and four high-melt-temperature polymers by LFAM machines released particulate and TVOC at levels that could warrant consideration of engineering controls. LFAM particle emission yields for some polymers were similar to those of common desktop-scale 3-D printers.

Large-Format Additive Manufacturing and Machining Using High-Melt-Temperature Polymers. Part II: Characterization of Particles and Gases.

Extrusion of high-melt-temperature polymers on large-format additive manufacturing (LFAM) machines releases particles and gases, though there is no data describing their physical and chemical characteristics. Emissions from two LFAM machines were monitored during extrusion of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) polymers as well as high-melt-temperature Ultem (poly(ether imide)), polysulfone (PSU), poly(ether sulfone) (PESU), and polyphenylene sulfide (PPS) polymers. Filter samples of particles were collected for quantification of elements and bisphenol A and S (BPA, BPS) and visualization of morphology. Individual gases were quantified on substance-specific media. Aerosol sampling demonstrated that concentrations of elements were generally low for all polymers, with a maximum of 1.6 mg/m3 for iron during extrusion of Ultem. BPA, an endocrine disruptor, was released into air during extrusion of PC (range: 0.4 ± 0.1 to 21.3 ± 5.3 µg/m3). BPA and BPS (also an endocrine disruptor) were released into air during extrusion of PESU (BPA, 2.0-8.7 µg/m3; BPS, 0.03-0.07 µg/m3). Work surfaces and printed parts were contaminated with BPA (<8-587 ng/100 cm2) and BPS (<0.22-2.5 ng/100 cm2). Gas-phase sampling quantified low levels of respiratory irritants (phenol, SO2, toluene, xylenes), possible or known asthmagens (caprolactam, methyl methacrylate, 4-oxopentanal, styrene), and possible occupational carcinogens (benzene, formaldehyde, acetaldehyde) in air. Characteristics of particles and gases released by high-melt-temperature polymers during LFAM varied, which indicated the need for polymer-specific exposure and risk assessments. The presence of BPA and BPS on surfaces revealed a previously unrecognized source of dermal exposure for additive manufacturing workers using PC and PESU polymers.

Undeclared formaldehyde levels in patient consumer products: formaldehyde test kit utility.

PURPOSE: Formaldehyde allergic contact dermatitis (ACD) may be due to products with free formaldehyde or formaldehyde-releasing agents; however, assessment of formaldehyde levels in such products is infrequently conducted. The present study quantifies total releasable formaldehyde from "in-use" products associated with formaldehyde ACD and tests the utility of commercially available formaldehyde spot test kits. MATERIALS AND METHODS: Personal care products from 2 patients with ACD to formaldehyde were initially screened at the clinic for formaldehyde using a formaldehyde spot test kit. Formaldehyde positive products were sent to the laboratory for confirmation by gas chromatography-mass spectrometry. In addition, 4 formaldehyde spot test kits were evaluated for potential utility in a clinical setting. RESULTS: Nine of the 10 formaldehyde spot test kit positive products obtained from formaldehyde allergic patients had formaldehyde with total releasable formaldehyde levels ranging from 5.4 to 269.4 µg/g. Of these, only two shampoos tested listed a formaldehyde-releasing agent in the ingredients or product literature. Subsequently, commercially available formaldehyde spot test kits were evaluated in the laboratory for ability to identify formaldehyde in personal care products. CONCLUSIONS: Chemical based formaldehyde spot test were more reliable than the enzymatic based test in identifying product releasable formaldehyde content. It is concluded that product labeled ingredient lists and available information are often inadequate to confirm the potential for formaldehyde exposure and chemical based spot test kits may have utility for identification of potential formaldehyde exposure from personal care products.

Three-dimensional printing with nano-enabled filaments releases polymer particles containing carbon nanotubes into air.

Fused deposition modeling (FDM™) 3-dimensional printing uses polymer filament to build objects. Some polymer filaments are formulated with additives, though it is unknown if they are released during printing. Three commercially available filaments that contained carbon nanotubes (CNTs) were printed with a desktop FDM™ 3-D printer in a chamber while monitoring total particle number concentration and size distribution. Airborne particles were collected on filters and analyzed using electron microscopy. Carbonyl compounds were identified by mass spectrometry. The elemental carbon content of the bulk CNT-containing filaments was 1.5 to 5.2 wt%. CNT-containing filaments released up to 1010 ultrafine (d < 100 nm) particles/g printed and 106 to 108 respirable (d ~0.5 to 2 µm) particles/g printed. From microscopy, 1% of the emitted respirable polymer particles contained visible CNTs. Carbonyl emissions were observed above the limit of detection (LOD) but were below the limit of quantitation (LOQ). Modeling indicated that, for all filaments, the average proportional lung deposition of CNT-containing polymer particles was 6.5%, 5.7%, and 7.2% for the head airways, tracheobronchiolar, and pulmonary regions, respectively. If CNT-containing polymer particles are hazardous, it would be prudent to control emissions during use of these filaments.

Identification and quantification of carbonyl-containing α-pinene ozonolysis products using O-tert-butylhydroxylamine hydrochloride.

The yields of carbonyl-containing reaction products from the ozonolysis of α-pinene have been investigated using concentrations of ozone found in the indoor environment ([O3] ≤ 100 ppb). An impinger was used to collect gas-phase oxidation products in water, where the derivatization agent O-tert-butylhydroxylamine hydrochloride (TBOX) and gas chromatography-mass spectrometry were used to identify carbonyl-containing species. Seven carbonyl-containing products were observed. The yield of the primary product, pinonaldehyde was measured to be 76 %. Using cyclohexane as a hydroxyl radical (OH) scavenger, the yield of pinonaldehyde decreased to 46 %, indicating the influence secondary OH radicals have on α-pinene ozonolysis products. Furthermore, the use of TBOX, a small molecular weight derivatization agent, allowed for the acquisition of the first mass spectral data of oxopinonaldehyde, a tricarbonyl reaction product of α-pinene ozonolysis. The techniques described herein allow for an effective method for the collection and identification of terpene oxidation products in the indoor environment.

A chamber study of alkyl nitrate production formed by terpene ozonolysis in the presence of NO and alkanes.

Organic nitrates are relatively long-lived species and have been shown to have a potential impact on atmospheric chemistry on local, regional, and even global scales. However, the significance of these compounds in the indoor environment remains to be seen. This work describes an impinger-based sampling and analysis technique for organic nitrate species, focusing on formation via terpene ozonolysis in the presence of nitric oxide (NO). Experiments were conducted in a Teflon film environmental chamber to measure the formation of alkyl nitrates produced from α-pinene ozonolysis in the presence of NO and alkanes using gas chromatography with an electron capture detector. For the different concentrations of NO and O3 analyzed, the concentration ratio of [O3]/[NO] around 1 was found to produce the highest organic nitrate concentration, with [O3] = 100 ppb & [NO] = 105 ppb resulting in the most organic nitrate formation, roughly 5 ppb. The experiments on α-pinene ozonolysis in the presence of NO suggest that organic nitrates have the potential to form in indoor air between infiltrated ozone/NO and terpenes from household and consumer products.

Limonene ozonolysis in the presence of nitric oxide: Gas-phase reaction products and yields.

The reaction products from limonene ozonolysis were investigated using the new carbonyl derivatization agent, O-tert-butylhydroxylamine hydrochloride (TBOX). With ozone (O3) as the limiting reagent, five carbonyl compounds were detected. The yields of the carbonyl compounds are discussed with and without the presence of a hydroxyl radical (OH•) scavenger, giving insight into the influence secondary OH radicals have on limonene ozonolysis products. The observed reaction product yields for limonaketone (LimaKet), 7-hydroxyl-6-oxo-3-(prop-1-en-2-yl)heptanal (7H6O), and 2-acetyl-5-oxohexanal (2A5O) were unchanged suggesting OH• generated by the limonene + O3 reaction does not contribute to their formation. The molar yields of 3-isopropenyl-6-oxo-heptanal (IPOH) and 3-acetyl-6-oxoheptanal (3A6O) decreased by 68% and >95%; respectively, when OH• was removed. This suggests that OH• radicals significantly impact the formation of these products. Nitric oxide (NO) did not significantly affect the molar yields of limonaketone or IPOH. However, NO (20 ppb) considerably decreased the molar reaction product yields of 7H6O (62%), 2A5O (63%), and 3A6O (47%), suggesting NO reacted with peroxyl intermediates, generated during limonene ozonolysis, to form other carbonyls (not detected) or organic nitrates. These studies give insight into the transformation of limonene and its reaction products that can lead to indoor exposures.

Gas-phase reaction products and yields of terpinolene with ozone and nitric oxide using a new derivatization agent.

The new derivatization agent, O-tert-butylhydroxylamine hydrochloride (TBOX) was used to investigate the carbonyl reaction products from terpinolene ozonolysis. With ozone (O3) as the limiting reagent, four carbonyl compounds were detected: methylglyoxal (MG), 4-methylcyclohex-3-en-1-one, (4MCH), 6-oxo-3-(propan-2-ylidene) heptanal (6OPH), and 3,6-dioxoheptanal (36DOH). The tricarbonyl 36DOH has not been previously observed. Using cyclohexane as a hydroxyl radical (OH•) scavenger, the yields of 6OPH and 36DOH were reduced indicating the influence secondary OH• radicals have on terpinolene ozonolysis products. However, the MG yield increased and the 4MCH yield was unchanged when OH•radicals were scavenged suggesting they are only made by the terpinolene + O3 reaction. The detection of 36DOH using TBOX highlights the advantages of a smaller molecular weight derivatization agent for the detection of multi-carbonyl compounds. The product yields from terpinolene ozonolysis experiments conducted in the presence of 20 ppb nitric oxide (NO) remained unchanged except for MG which decreased. However, in experiments where O3 was kept constant at 50 ppb and NO was varied (20, 50, 100 ppb) MG, 6OPH, 36DOH decreased with increasing NO while 4MCH increased with increasing NO. The use of TBOX derivatization if combined with other derivatization agents may address a recurring need to simply and accurately detect multi-functional oxygenated species in air.

A new agent for derivatizing carbonyl species used to investigate limonene ozonolysis.

A new method for derivatizing carbonyl compounds is presented. The conversion of a series of dicarbonyls to oximes in aqueous solution and from gas-phase sampling was achieved using O-tert-butyl-hydroxylamine hydrochloride (TBOX). Some advantages of using this derivatization agent include: aqueous reactions, lower molecular weight oximes, and shortened oxime-formation reaction time. Additionally, the TBOX derivatization technique was used to investigate the carbonyl reaction products from limonene ozonolysis. With ozone (O3) as the limiting reagent, four carbonyl compounds were detected: 7-hydroxy-6-oxo-3-(prop-1-en-2-yl)heptanal; 3-Isopropenyl-6-oxoheptanal (IPOH), 3-acetyl-6-oxoheptanal (3A6O) and one carbonyl of unknown structure. Using cyclohexane as a hydroxyl (OH•) radical scavenger, the relative yields (peak area) of the unknown carbonyl, IPOH, and 3A6O were reduced indicating the influence secondary OH radicals have on limonene ozonolysis products. The relative yield of the hydroxy-dicarbonyl based on the chromatogram was unchanged suggesting it is only made by the limonene + O3 reaction. The detection of 3A6O using TBOX highlights the advantages of a smaller molecular weight derivatization agent for the detection of multi-carbonyl compounds. The use of TBOX derivatization if combined with other derivatization agents may address a recurring need to simply and accurately detect multi-functional oxygenated species in air.

Cavity ring-down spectroscopy with an automated control feedback system for investigating nitrate radical surface chemistry reactions.

Nitrate radical (NO(3)(●)) surface chemistry of indoor environments has not been well studied due to the difficulty in generating and maintaining NO(3)(●) at low concentrations for long term exposures. This article presents the Surface Chemistry Reactant Air Delivery and Experiment System (SCRADES), a novel feedback controlled system developed to deliver nitrate radicals at specified concentrations (50-500 ppt, ±30 ppt) and flow rates (500-2000 ml min(-1)) to a variety of indoor surfaces to initiate reaction chemistry for periods of up to 72 h. The system uses a cavity ring-down spectrometer (CRDS), with a detection limit of 1.7 ppt, to measure the concentration of NO(3)(●) supplied to a 24 l experiment chamber. Nitrate radicals are introduced via thermal decomposition of N(2)O(5) and diluted with clean dry air until the desired concentration is achieved. Additionally, this article addresses details concerning NO(3)(●) loss through the system, consistency of the NO(3)(●) concentration delivered, and stability of the CRDS cavity over long exposure durations (72 h).

Irritancy and allergic responses induced by exposure to the indoor air chemical 4-oxopentanal.

Over the last two decades, there has been an increasing awareness regarding the potential impact of indoor air pollution on human health. People working in an indoor environment often experience symptoms such as eye, nose, and throat irritation. Investigations into these complaints have ascribed the effects, in part, to compounds emitted from building materials, cleaning/consumer products, and indoor chemistry. One suspect indoor air contaminant that has been identified is the dicarbonyl 4-oxopentanal (4-OPA). 4-OPA is generated through the ozonolysis of squalene and several high-volume production compounds that are commonly found indoors. Following preliminary workplace sampling that identified the presence of 4-OPA, these studies examined the inflammatory and allergic responses to 4-OPA following both dermal and pulmonary exposure using a murine model. 4-OPA was tested in a combined local lymph node assay and identified to be an irritant and sensitizer. A Th1-mediated hypersensitivity response was supported by a positive response in the mouse ear swelling test. Pulmonary exposure to 4-OPA caused a significant elevation in nonspecific airway hyperreactivity, increased numbers of lung-associated lymphocytes and neutrophils, and increased interferon-γ production by lung-associated lymph nodes. These results suggest that both dermal and pulmonary exposure to 4-OPA may elicit irritant and allergic responses and may help to explain some of the adverse health effects associated with poor indoor air quality.

Surface chemistry of a pine-oil cleaner and other terpene mixtures with ozone on vinyl flooring tiles.

Indoor environments are dynamic reactors where consumer products (such as cleaning agents, deodorants, and air fresheners) emit volatile organic compounds (VOCs) that can subsequently interact with indoor oxidants such as ozone (O(3)), hydroxyl radicals, and nitrate radicals. Typically, consumer products consist of mixtures of VOCs and semi-VOCs which can react in the gas-phase or on surfaces with these oxidants to generate a variety of oxygenated products. In this study, the reaction of a pine-oil cleaner (POC) with O(3) (100ppb) on a urethane-coated vinyl flooring tile was investigated at 5% and 50% relative humidity. These results were compared to previous α-terpineol+O(3) reactions on glass and vinyl surfaces. Additionally, other terpene and terpene alcohol mixtures were formulated to understand the emission profiles as seen in the POC data. Results showed that the α-terpineol+O(3) reaction products were the prominent species that were also observed in the POC/O(3) surface experiments. Furthermore, α-terpineol+O(3) reactions generate the largest fraction of oxygenated products even in equal mixtures of other terpene alcohols. This finding suggests that the judicial choice of terpene alcohols for inclusion in product formulations may be useful in reducing oxidation product emissions.

Feasibility of detection and quantification of gas-phase carbonyls in indoor environments using PFBHA derivatization and solid-phase microextraction (SPME).

Solid-phase microextraction (SPME) was evaluated for the detection and quantification of the gas-phase carbonyls: citronellal, glyoxal, methylglyoxal, and beta-ionone. Prepared air samples containing the carbonyl compounds were collected at a flow rate of 2.8 L min(-1) in an impinger containing a 25% reagent water/75% methanol collection liquid. The aqueous samples were then derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), extracted with a PDMS/DVB coated SPME fiber, and analyzed by GC-MS. Detection limits with a sample air volume of 76 L were calculated to be 0.03 ppbv, 0.34 ppbv, 0.12 ppbv, and 0.28 ppbv for citronellal, glyoxal, methylglyoxal, and beta-ionone, respectively.

Irritancy and sensitization potential of glyoxylic acid.

Glyoxylic acid, a small dicarboxylic acid, has been detected at measurable levels in the atmosphere and is suspected to be present in indoor air environments. It is generated through the ozonolysis of several high volume production compounds that are commonly found indoors. Glyoxylic acid was tested in a combined irritancy and local lymph node assay (LLNA). It tested positive in the LLNA with an EC3 value of 5.05%. Significant increases were observed in the B220+cell population in the draining lymph nodes. No changes were identified in the IgE+B220+ cell population in the draining lymph nodes or total serum IgE levels; this suggests that glyoxylic acid functions as a T-cell-mediated contact sensitizer. Exposure to volatile organic compounds (VOC), similar to glyoxylic acid, emitted from building materials, cleaning formulations or other consumer products, and /or indoor chemistry have been linked to adverse health effects. These results may provide an explanation for some of adverse health effects associated with indoor air exposure.

Field and laboratory emission cell automation and control system for investigating surface chemistry reactions.

A novel system [field and laboratory emission cell (FLEC) automation and control system] has been developed to deliver ozone to a surface utilizing the FLEC to simulate indoor surface chemistry. Ozone, humidity, and air flow rate to the surface were continuously monitored using an ultraviolet ozone monitor, humidity, and flow sensors. Data from these sensors were used as feedback for system control to maintain predetermined experimental parameters. The system was used to investigate the chemistry of ozone with alpha-terpineol on a vinyl surface over 72 h. Keeping all other experimental parameters the same, volatile organic compound emissions from the vinyl tile with alpha-terpineol were collected from both zero and 100 ppb (parts per 10(9)) ozone exposures. System stability profiles collected from sensor data indicated experimental parameters were maintained to within a few percent of initial settings. Ozone data from eight experiments at 100 ppb (over 339 h) provided a pooled standard deviation of 1.65 ppb and a 95% tolerance of 3.3 ppb. Humidity data from 17 experiments at 50% relative humidity (over 664 h) provided a pooled standard deviation of 1.38% and a 95% tolerance of 2.77%. Data of the flow rate of air flowing through the FLEC from 14 experiments at 300 ml/min (over 548 h) provided a pooled standard deviation of 3.02 ml/min and a 95% tolerance range of 6.03 ml/min. Initial experimental results yielded long term emissions of ozone/alpha-terpineol reaction products, suggesting that surface chemistry could play an important role in indoor environments.

Use of solid-phase microextraction to detect and quantify gas-phase dicarbonyls in indoor environments.

Solid-phase microextraction (SPME) was evaluated for the detection and quantification of the gas-phase dicarbonyls, glyoxal (GLY) and methylglyoxal (MGLY). Additionally, polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB), and carbowax/divinylbenzene (CW/DVB) fibers were tested to determine the optimum fiber for detection of these species. GLY and MGLY were derivatized with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA), extracted with SPME from headspace or bag chamber and then analyzed by GC/MS. The PDMS/DVB SPME fiber for on-fiber derivatization and subsequent sampling for gas-phase methylglyoxal provided the optimum combination of analytical reproducibility and sensitivity. Linearity of the calibration curve was achieved across a range of 11-222 microg/m(3) (4-75 ppb).

Comparison of laser desorption and matrix-assisted laser desorption/ionization for ruthenium and osmium trisbipyridine complexes using Fourier transform mass spectrometry.

Metal-bipyridine complexes are a vehicle for developing approaches for studying the fluorescence of gas-phase ions; however, conclusions regarding fluorescence behavior depend on explicitly identifying the ionic species in the gas phase. [Ru(bpy)(3)]X(2) and [Os(bpy(3))]X(2), (where bpy = 2,2'-bipyridine and X = Cl or PF(6)), were studied using direct laser desorption (LD) and matrix-assisted laser desorption/ionization (MALDI) using Fourier transform mass spectrometry (FTMS). LD spectra of the PF(6) salt of the Ru and Os complexes reveal counterion attachment, fluoride transfer, and significant losses of H for a number of peaks. LD of the chloride salt complexes produced loss of a single bpy ligand, chloride attachment, and losses of H. Spectra of [Ru(bpy(3)]X(2) where X = BF(4)(-), CF(3)SO(3)(-), and SCN(-) were also collected using LD and compared with the spectra for Cl(2) and PF(6) salts. Regardless of counterion, loss of H is observed in LD spectra. MALDI spectra of the trisbipyridyl complexes using 2,5-dihydroxybenzoic acid (DHB) and sinapinic acid (SA) as the matrix were also obtained. The spectra using SA as matrix show intact molecular ion peaks with very little fragmentation and no counterion attachment. Unlike SA, the spectra obtained using DHB look similar to LD spectra with significant losses of H. Our results are consistent with a reaction scheme for hydrogen loss from a carbon that also involves breaking of the metalz.sbnd;nitrogen bond, rotation of a pyridine ring, and re-formation of an ortho-metallated complex by a metalz.sbnd;C bond. These results demonstrate the importance of ion generation method and the utilization of FTMS for correct characterization of metal poly(pyridyl) complexes.