The quantitative surface analysis of an antioxidant additive in a lubricant oil matrix by desorption electrospray ionization mass spectrometry

Rationale Chemical additives are incorporated into commercial lubricant oils to modify the physical and chemical properties of the lubricant. The quantitative analysis of additives in oil-based lubricants deposited on a surface without extraction of the sample from the surface presents a challenge. The potential of desorption electrospray ionization mass spectrometry (DESI-MS) for the quantitative surface analysis of an oil additive in a complex oil lubricant matrix without sample extraction has been evaluated. Methods The quantitative surface analysis of the antioxidant additive octyl (4-hydroxy-3,5-di-tert-butylphenyl)propionate in an oil lubricant matrix was carried out by DESI-MS in the presence of 2-(pentyloxy)ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate as an internal standard. A quadrupole/time-of-flight mass spectrometer fitted with an in-house modified ion source enabling non-proximal DESI-MS was used for the analyses. RESULTS An eight-point calibration curve ranging from 1 to 80 μg/spot of octyl (4-hydroxy-3,5-di-tert-butylphenyl)propionate in an oil lubricant matrix and in the presence of the internal standard was used to determine the quantitative response of the DESI-MS method. The sensitivity and repeatability of the technique were assessed by conducting replicate analyses at each concentration. The limit of detection was determined to be 11 ng/mm additive on spot with relative standard deviations in the range 3-14%. CONCLUSIONS The application of DESI-MS to the direct, quantitative surface analysis of a commercial lubricant additive in a native oil lubricant matrix is demonstrated

Direct analysis of oil additives by high-field asymmetric waveform ion mobility spectrometry-mass spectrometry combined with electrospray ionization and desorption electrospray ionization

© 2016 American Chemical Society. The analysis of corrosion inhibitors in the presence and absence of an oil matrix is reported using electrospray ionization (ESI) and desorption electrospray ionization (DESI), hyphenated with miniaturized high-field asymmetric waveform ion mobility spectrometry (FAIMS) and mass spectrometry (MS). The target analytes were successfully ionized in solution by ESI and directly from steel surfaces using DESI ambient ionization at levels ≥0.0004% w/w (4 ppm) in oil. Differences in the mass spectral profiles observed for the additive/oil mixture are attributed to differences between the ESI and DESI ionization processes. The use of FAIMS improved selectivity for ESI generated analyte ions through reduction in the chemical noise resulting from the oil matrix. DESI enabled the direct, rapid, native state interrogation of oil samples on steel surfaces without sample pretreatment, and the hyphenation of DESI with the miniaturized FAIMS enhanced the relative analyte responses of the surface-active corrosion inhibitors

How to establish the outer limits of reperfusion therapy

Reperfusion therapy with intravenous alteplase and endovascular therapy are effective treatments for selected patients with acute ischemic stroke. Guidelines for treatment are based upon randomized trials demonstrating substantial treatment effects for highly selected patients based on time from stroke onset and imaging features. However, patients beyond the current established guidelines might benefit with lesser but still clinically significant treatment effects. The STAIR (Stroke Treatment Academic Industry Roundtable) XI meeting convened a workgroup to consider the “outer limits” of reperfusion therapy by defining the current boundaries, and exploring optimal parameters and methodology for determining the outer limits. In addition to statistical significance, the minimum clinically important difference should be considered in exploring the limits of reperfusion therapy. Societal factors and quality of life considerations should be incorporated into assessment of treatment efficacy. The threshold for perception of benefit in the medical community may differ from that necessary for the Food and Drug Administration approval. Data from alternative sources such as platform trials, registries and large pragmatic trials should supplement randomized controlled trials to improve generalizability to routine clinical practice. Further interactions between industry and academic centers should be encouraged

The qualitative and quantitative analysis of lubricant oil additives by direct analysis in real time-mass spectrometry

The application of direct analysis in real time combined with mass spectrometry (DART-MS) to the qualitative analysis of lubricant and oil additives, and the quantitative analysis of a lubricant antioxidant additive is reported. The additives were analysed alone and in the presence of a base oil, from filter paper, glass and steel surfaces, showing the potential of the DART-MS technique for the direct, rapid analysis of lubricant oil additives. The quantitative capabilities of the technique were evaluated for the antioxidant in an oil matrix at concentrations in the range 0.1-8mg/mL in oil (1-80μg antioxidant on spot), using a structural analogue of the antioxidant as an internal standard. The linearity (R2 =0.997), precision (% RSD=2.6%) and LOD (0.04mg/mL in oil) of the method demonstrates that DART-MS is capable of the rapid determination of additives in oil without pre-extraction

\u3cem\u3eIn the Place of Justice\u3c/em\u3e Reading Guide

What happens to a man when he is stripped of his freedom? What happens to a person when they are told they aren’t deserving of a fair chance? These are questions that, thankfully, very few people ever have to answer. Most are lucky to be born into a world where they are treated equally by those around them. Wilbert Rideau was not so lucky; he was born into a world that said he didn\u27t matter. Trapped inside Jim Crow society with very few opportunities, Rideau would eventually make the choice to commit a terrible crime. In the aftermath of his actions, he would go on to spend forty-four years in one of the most violent prisons in America. During those years he would face and overcome challenges that no person should ever be faced with. During his time in prison, Rideau experienced pain, despair, rejuvenation, and redemption amongst other hardships within the American Justice System. He also grew into an eloquent advocate for prisoners, prison reform and prisoners\u27 civil rights as well as into a thoughtful journalist and memoirist

\u3cem\u3eThe Sojourn\u3c/em\u3e Reading Guide

World War I was said to be the war to end all wars. But who were the men that fought this war? What happened to them before they were soldiers? And what remained after? Andrew Krivak\u27s short novel The Sojourn, offers some answers to these questions as well as offering a meditation on language and storytelling as tools for promoting peace. Words and shared language build relationships in this book. And at the end of the Great War, which consumes the middle portion of the novel, the shadow of these relationships is what remains, along with the remnants of a destroyed Empire. It is from these ashes of society and identity that Jozef Vinich must rise or burn and which ashes readers must sift to discover the root of peace. After all, this is a book on which The Dayton Literary Peace Prize was bestowed

Direct Analysis of Oil Additives by High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometry Combined with Electrospray Ionization and Desorption Electrospray Ionization

This is an Open Access Article. It is published by American Chemical Society under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/© 2016 American Chemical Society. The analysis of corrosion inhibitors in the presence and absence of an oil matrix is reported using electrospray ionization (ESI) and desorption electrospray ionization (DESI), hyphenated with miniaturized high-field asymmetric waveform ion mobility spectrometry (FAIMS) and mass spectrometry (MS). The target analytes were successfully ionized in solution by ESI and directly from steel surfaces using DESI ambient ionization at levels ≥0.0004% w/w (4 ppm) in oil. Differences in the mass spectral profiles observed for the additive/oil mixture are attributed to differences between the ESI and DESI ionization processes. The use of FAIMS improved selectivity for ESI generated analyte ions through reduction in the chemical noise resulting from the oil matrix. DESI enabled the direct, rapid, native state interrogation of oil samples on steel surfaces without sample pretreatment, and the hyphenation of DESI with the miniaturized FAIMS enhanced the relative analyte responses of the surface-active corrosion inhibitors

Application of the D3‐creatine muscle mass assessment tool to a geriatric weight loss trial: A pilot study

BackgroundTraditionally, weight loss (WL) trials utilize dual energy X-ray absorptiometry (DXA) to measure lean mass. This method assumes lean mass, as the sum of all non-bone and non-fat tissue, is a reasonable proxy for muscle mass. In contrast, the D3 -creatine (D3 Cr) dilution method directly measures whole body skeletal muscle mass, although this method has yet to be applied in the context of a geriatric WL trial. The purpose of this project was to (1) describe estimates of change and variability in D3 Cr muscle mass in older adults participating in an intentional WL intervention and (2) relate its change to other measures of body composition as well as muscle function and strength.MethodsThe INVEST in Bone Health trial (NCT04076618), used as a scaffold for this ancillary pilot project, is a three-armed, 12-month randomized, controlled trial designed to determine the effects of resistance training or weighted vest use during intentional WL on a battery of musculoskeletal health outcomes among 150 older adults living with obesity. A convenience sample of 24 participants (n = 8/arm) are included in this analysis. At baseline and 6 months, participants were weighed, ingested a 30 mg D3 Cr tracer dose, provided a fasted urine sample 3-6 days post-dosage, underwent DXA (total body fat and lean masses, appendicular lean mass) and computed tomography (mid-thigh and trunk muscle/intermuscular fat areas) scans, and performed 400-m walk, stair climb, knee extensor strength, and grip strength tests.ResultsParticipants were older (68.0 ± 4.4 years), mostly White (75.0%), predominantly female (66.7%), and living with obesity (body mass index: 33.8 ± 2.7 kg/m2 ). Six month total body WL was -10.3 (95% confidence interval, CI: -12.7, -7.9) kg. All DXA and computed tomography-derived body composition measures were significantly decreased from baseline, yet D3 Cr muscle mass did not change [+0.5 (95% CI: -2.0, 3.0) kg]. Of muscle function and strength measures, only grip strength significantly changed [+2.5 (95% CI: 1.0, 4.0) kg] from baseline.ConclusionsAmong 24 older adults, significant WL with or without weighted vest use or resistance training over a 6-month period was associated with significant declines in all bioimaging metrics, while D3 Cr muscle mass and muscle function and strength were preserved. Treatment assignment for the trial remains blinded; therefore, full interpretation of these findings is limited. Future work in this area will assess change in D3 Cr muscle mass by parent trial treatment group assignment in all study participants

\u3cem\u3eBrother, I\u27m Dying\u3c/em\u3e Reading Guide

When political unrest and death surround a family, how do they find peace? In Brother, I’m Dying, Edwidge Danticat explores this question in her memoir of two brothers and the families they raised. Through the course of their lives many issues of interest to peace readers are explored, from the devastating impact on individual lives of foreign intervention in Haiti and US immigration policy, to the strengthening bonds of family and their resistance to severance by death