White by Another Name? Can Anti-Christian Bias Claims Serve as a Racial Dog Whistle?

Four preregistered experiments (N = 4,307) explored whether anti-Christian bias claims can discreetly signal White allyship among Christian American adults. In Experiments 1 and 2, reading about anti-Christian bias led White, but not Black, Christians to perceive more anti-White bias. Experiments 3 and 4 demonstrate the connection between Christian and White can be leveraged by politicians in the form of a racial dog whistle. In Experiment 3, White Christians perceived a politician concerned about anti-Christian bias as caring more about anti-White bias and more willing to fight for White people (relative to a control). This politician was also perceived as less offensive than a politician concerned about anti-White bias. In Experiment 4, Black Christians perceived a politician concerned about anti-Christian bias as less offensive than one concerned about anti-White bias yet still unlikely to fight for Black people. Results suggest "anti-Christian bias" can provide a relatively palatable way to signal allegiance to White people.

Anti-Black attitudes predict decreased concern about COVID-19 among Whites in the U.S. and Brazil

RATIONALE

From the earliest days of the COVID-19 pandemic, public health officials and news organizations reported pervasive racial disparities in the infection, morbidity, and mortality of the virus. In both the U.S. and Brazil, Black, Native, and mixed-race individuals were more negatively impacted by COVID-19 than White people. Simultaneously, significant social factions downplayed the threat and insisted on living "normally". We examined how these two factors coexisted.

OBJECTIVE

We sought to establish whether Whites' anti-Black attitudes predicted their concern about the pandemic and tendency to behave in ways that exacerbated the pandemic.

METHODS

and Results: In five studies, conducted in two countries (total N = 3425), we found that anti-Black attitudes (above and beyond political orientation, White racial identification, and perceptions of racial disparities) were associated with less concern about COVID-19, lower adoption of health and social distancing behaviors, and greater interest in returning to normalcy.

DISCUSSION

We discuss how efforts to combat anti-Blackness may improve the health of the general population.

Backlash against the #MeToo movement: How women’s voice causes men to feel victimized

Three studies examined whether perceived increase in women’s “voice” (i.e., being heard and taken seriously about sexual assault) contributes to perceptions of bias against men. In Study 1, both men and women who perceived women to have a greater voice related to sexual assault, perceived greater victimization of men. This relationship was stronger for relatively conservative participants. In Study 2, relatively conservative (but not relatively liberal) participants who read about #MeToo perceived greater men’s victimization than those in the control condition. Study 3 examined responses to perceiving that men are victimized by #MeToo. For relatively conservative (but not liberal) men, perceptions of men’s victimhood led to less willingness to work alone with a woman and less willingness to combat sexual assault (relative to a control condition). Thus, while the #MeToo movement brings awareness of issues of sexual assault, it also generates a backlash among the more conservative, and may accentuate gender disparities.

The Pandemic as a Portal: Reimagining Psychological Science as Truly Open and Inclusive

Psychological science is at an inflection point: The COVID-19 pandemic has exacerbated inequalities that stem from our historically closed and exclusive culture. Meanwhile, reform efforts to change the future of our science are too narrow in focus to fully succeed. In this article, we call on psychological scientists-focusing specifically on those who use quantitative methods in the United States as one context for such conversations-to begin reimagining our discipline as fundamentally open and inclusive. First, we discuss whom our discipline was designed to serve and how this history produced the inequitable reward and support systems we see today. Second, we highlight how current institutional responses to address worsening inequalities are inadequate, as well as how our disciplinary perspective may both help and hinder our ability to craft effective solutions. Third, we take a hard look in the mirror at the disconnect between what we ostensibly value as a field and what we actually practice. Fourth and finally, we lead readers through a roadmap for reimagining psychological science in whatever roles and spaces they occupy, from an informal discussion group in a department to a formal strategic planning retreat at a scientific society.

Is LGBT progress seen as an attack on Christians?: Examining Christian/sexual orientation zero-sum beliefs

As social policies have changed to grant more rights to lesbian, gay, bisexual, and transgender (LGBT) individuals, some Christians in the United States have suggested that LGBT rights impede Christians' religious freedom. Across five studies, we examined the causes and consequences of zero-sum beliefs (ZSBs) about Christians and LGBT individuals. We demonstrate that Christians' beliefs about conflict with sexual minorities are shaped by their understandings of Christian values, social change, interpretation of the Bible, and in response to religious institutions. In Study 1, heterosexual cisgender Christians endorsed ZSBs more than other groups. Christians reported perceiving that anti-LGBT bias has decreased over time while anti-Christian bias has correspondingly increased. In Study 2, Christians' zero-sum beliefs increased after they reflected on religious values, suggesting that intergroup conflict is seen as being a function of Christian beliefs. Study 3 confirmed the role of symbolic threat in driving ZSBs; perceived conflict was accentuated when Christians read about a changing cultural climate in which Christians' influence is waning. An intervention using Biblical scripture to encourage acceptance successfully lowered zero-sum beliefs for mainline but not fundamentalist Christians (Study 4). A final field study examined how ZSBs predict sexual prejudice in response to changing group norms. After a special conference in which the United Methodist Church voted to restrict LGBT people from marriage and serving as clergy, zero-sum beliefs became a stronger predictor of sexual prejudice (Study 5). We discuss the implications of Christian/LGBT ZSBs for religious freedom legislation, attitudes toward sexual minorities, and intergroup conflict more generally. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Conflicting Motivations: Understanding How Low-Status Group Members Respond to Ingroup Discrimination Claimants

Previous research has found that among low-status individuals, both group identification (GID) and status-legitimizing beliefs (SLBs) motivate varying responses to ingroup discrimination claimants. SLBs are traditionally thought to motivate decreased support for low-status claimants, while GID is thought to motivate increased liking and support of ingroup members. The current research examines these conflicting influences on ingroup claimants among women (Studies 1a and 1b) and Latino/as (Studies 2 and 3). We find that when SLBs are strongly endorsed (Studies 1a, 1b, and 2) or primed (Study 3), GID does not predict liking or support for a claimant. Only when SLB endorsement is low and identity safety cues are absent does GID predict liking and support for a claimant. Our results suggest that when motivations conflict, SLBs seem to more strongly predict reactions to ingroup claimants.

Reactions to anti-male sexism claims: The moderating roles of status-legitimizing belief endorsement and group identification

Men increasingly identify as victims of gender discrimination, but it is unclear how people react to men who claim to be victims of gender bias. We examined how status-legitimizing belief endorsement (SLBs) and gender identification (GID) moderated men and women’s reactions to a man who claimed to have lost a promotion because of anti-male sexism or another cause. Consistent with theory that claiming bias against high-status groups reinforces the status hierarchy, SLB endorsement was associated with more positive reactions toward an anti-male bias claimant for both men and women. Group identification, in contrast, affects group-specific concerns and thus differentially predicted male and female participants’ reactions. Men evaluated the claimant more positively the more strongly they identified with their gender. The more women identified with their gender, the more negatively they evaluated the male claimant. We also demonstrated that SLBs and GID moderated the extent to which the claimant was perceived as sexist. We discuss how these reactions may perpetuate gender inequality.

The threat of racial progress and the self-protective nature of perceiving anti-White bias

In two studies we tested whether racial progress is threatening to Whites and whether perceiving anti-White bias assuages that threat. Study 1 revealed that Whites primed with racial progress exhibited evidence of threat (lower implicit self-worth relative to baseline). Study 2 replicated the threat effect from Study 1 and examined how perceiving discrimination may buffer Whites’ self-worth. After White participants primed with high racial progress attributed a negative event to their race, their implicit self-worth rebounded. Participants primed to perceive low racial progress did not experience fluctuations in implicit self-worth. Furthermore, among those primed with high racial progress, greater racial discounting (attributing rejection to race rather than to the self) was associated with greater self-worth protection. These studies suggest that changes to the racial status quo are threatening to Whites and that perceiving greater racial bias is a way to manage that threat.

Priming status-legitimizing beliefs: Examining the impact on perceived anti-White bias, zero-sum beliefs, and support for Affirmative Action among White people

The current research examines how status-legitimizing beliefs (SLBs) influence White people's perceptions of anti-White bias, endorsement of zero-sum beliefs, and support for Affirmative Action. We suggest that SLBs perpetuate inequality by increasing White people's perceptions of zero-sum beliefs and anti-White bias, which in turn lead to decreased support for Affirmative Action. White individuals primed with SLBs perceived greater anti-White bias, endorsed greater zero-sum beliefs, and indicated less support for Affirmative Action than individuals primed with neutral content. Mediation analysis revealed that the SLB prime decreased support for Affirmative Action by increasing perceptions of anti-White bias. This research offers experimental evidence that SLBs contribute to White people's perceptions of anti-White bias and to decreased support for Affirmative Action.

Racial progress as threat to the status hierarchy: implications for perceptions of anti-White bias

In three studies, we examined how racial progress affects Whites' perceptions of anti-White bias. When racial progress was chronically (Study 1) and experimentally (Study 2) salient, Whites who believed the current U.S. status hierarchy was legitimate were more likely to report that Whites were victims of racial discrimination. In contrast, Whites who perceived the current status system as illegitimate were unaffected by the salience of racial progress. The results of Study 3 point to the role of threat in explaining these divergent reactions to racial progress. When self-affirmed, Whites who perceived the status hierarchy as legitimate no longer showed increased perceptions of anti-White bias when confronted with evidence of racial progress. Implications for policies designed to remedy social inequality are discussed.

Gas chromatography with spectroscopic detectors

In recent years, capillary gas chromatography (GC) with Fourier Transform Infrared (FT-IR) and/or mass spectral (MS) detection has become a primary analytical tool for qualitative and quantitative analysis of complex mixtures. Because of the wide range of applications, the analytical requirements have motivated a variety of chromatographic and detection developments. This review examines those, illustrating with applications that demonstrate the power of GC and multidimensional GC-MS, GC-FT-IR and GC-FT-IR-MS systems for solving a variety of analytical problems. In addition, the article discusses the integrated performance of such analytical systems with the aid of recent sample introduction and computer data analysis advances.

Fragmentation of an alkali metal-attached peptide probed by collision-induced dissociation fourier transform mass spectrometry and computational methodology

Collision-induced dissociation of metal-cationized N-CBZ-Gly-Pro-Gly-Pro-Ala was studied by Fourier transform mass spectrometry. Lithium-, sodium-, potassium- and rubidium-cationized peptide species were generated by matrix-assisted laser desorption/ionization (MALDI) using 2,5-dihydroxybenzoic acid as matrix, together with appropriate metal salts. The experimental mass spectrometric results were interpreted with the aid of Monte Carlo conformational searches using the Amber(*) force field, together with ab initio molecular orbital calculations with Gaussian-94 for the singly lithium- and potassium-cationized peptides. It is concluded that metal coordination plays a key role in guiding the gas-phase fragmentation of the cationized peptide. In contrast to lithium and sodium, potassium and rubidium apparently do not coordinate to the C-terminal carbonyl. When the peptide is cationized with the two smaller alkali metals, losses corresponding to alanine and CBZ are observed, while the coordination of potassium and rubidium results in only CBZ loss upon dissociation.

Investigation of low-voltage on-resonance ion selection for Fourier transform mass spectrometry

Low-voltage on-resonance ion selection (LOIS) was recently introduced as an alternative technique for ion selection and storage. Under high pressure conditions and similar to the technique of quadrupolar axialization, unwanted (unselected) trapped ions are eliminated from the analysis cell through collisions with cell plates following orbital expansion. The ions remaining after tens of seconds of mass selection can be detected with better coherence, leading to improvements in ion detection and sensitivity. Here, experiments designed to test ion remeasurement and ion transfer capabilities are presented. Simulations of ion motion give insight into the possible mechanism of ion cooling, which does appear to be the same as that of the axialization process. Because of its ease of use, lack of need for additional hardware devices, and comparable ion selection results, LOIS is an attractive alternative for trapped ion experiments.

Importance of matrix:analyte ratio for buffer tolerance using 2,5-dihydroxybenzoic acid as a matrix in matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry and matrix-assisted laser desorption/ionization-time of flight

Many biological samples destined for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) contain buffers. The presence of these buffers often inhibits the ability to obtain spectra. Here, the results of a study of the effects of six different buffers on spectra of three representative small proteins are reported utilizing 2,5-dihydroxybenzoic acid as matrix. These proteins, bovine insulin, cytochrome c, and bovine albumin have masses from approximately 5000 to 66,000 Da. Three different sample preparation techniques were investigated: aerospray, dried-drop, and acetone redeposition. Both MALDI Fourier transform and time-of-flight mass spectrometry results show that buffer tolerance of MALDI-MS samples depends upon several factors, including the relative amount of the buffer in the MALDI matrix, as well as the identity of the specific buffer. Furthermore, the rate at which buffer tolerance decreases as buffer concentration is increased varies from buffer to buffer. The current results reveal that, at very high matrix:analyte ratios, buffer tolerance of MALDI is dramatically greater than concluded in previous literature reports.

Poly(ethylene glycol) limits of detection using internal matrix-assisted laser desorption/ionization Fourier transform mass spectrometry

Detection limits of poly(ethylene glycol) were examined in the mass range 2000-6000 Da. Using an aerospray sample deposition technique, highly uniform sample surfaces were produced. This method allows signal averaging of spectra from up to 400 shots on the same sample spot. It is found that, as the material available for desorption is decreased, the overall average sample consumption per shot is decreased. Experimentally determined detection limits of 40 and 280 fmol (based on the average molecular masses of 2000 and 6000) were found for PEG 2000 and PEG 6000, respectively. The sample spectra show oligomer distributions in agreement with their higher concentration counterparts. However, at the lowest signal-to-noise levels, oligomers at the extremes of the distribution are no longer detected, making the polymer distribution appear to be narrower in mass range.

Fourier transform mass spectrometry-advancing years (1992-mid. 1996)

This article is one of a series of Fourier transform mass spectrometry (FTMS) reviews that has appeared in this journal at ca. 3-4 year intervals. A comprehensive review of the recent theoretical developments, instrumental developments, electrospray ionization (ESI), and MALDI is given. Ion dissociation techniques are also discussed because of their contributions to gaining insight into chemical structure. Special sections have been devoted to discussing the emerging fields of surface analysis, polymer analysis, Buckminsterfullerenes (buckyballs), and hydrogen/deuterium exchange studies. This review, although not all-inclusive, is intended to be a starting point for those wishing to learn more about the current status of FTMS, and also as a representative cross-section of the literature for those familiar with the technique. © 1997 John Wiley & Sons, Inc.

Applications of multidimensional-gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared-mass spectrometry

Gas chromatography systems with coupled columns in a multidimensional (MD) mode have become more important for the analysis of complex mixtures, due to the increased selectivity that can be achieved by the use of multiple columns with differing stationary phases. Coupling two or more detectors can also help to increase the information content of the analysis. This review presents the various strategies used in multidimensional gas chromatography (MDGC), with Fourier transform infrared (FT-IR) and/or mass spectrometric (MS) detection, with an emphasis on applications of these techniques for analysis of components in complex matrices. © 1997 John Wiley & Sons, Inc.

Off-line coupling of capillary electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

An automated fraction collection interface is used in conjunction with matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry to analyze material isolated by capillary electrophoresis (CE). CE fractions are deposited directly on the MALDI probes so that individual peaks from the electropherogram are associated with a single sample spot on the probe. MALDI matrices with high acid concentrations afford enhanced tolerance of electrophoresis buffers. The utility of this hybrid instrument is demonstrated by separation and mass analysis of a tryptic digest of cytochrome c and synthetic mixtures of four proteins. Mass assignments corresponding to the protonated molecular ions are in good agreement with those predicted from molecular structure. Miniaturization of the interface affords enhanced sensitivity, with good-quality spectra from separations of as little as 25 fmol of protein.

Analysis of high-mass biomolecules using electrostatic fields and matrix-assisted laser desorption/ionization in a Fourier transform mass spectrometer

A new decelerating technique that places dc potentials on the orthogonal excitation and receiver plates as well as the rear trapping plate (conductance limit) of the source cell of a dual cubic cell has been applied to the standard matrix-assisted laser desorption/ionization Fourier transform mass spectrometry technique. When this five-plate trapping method is applied, high-mass ions with large translational kinetic energies can be trapped efficiently and detected. Using this approach, low-resolution spectra of carbonic anhydrase (MW = 29,000), egg albumin (MW = 45,000), and bovine albumin (MW = 66,000) have been obtained. Because the new decelerating method requires no modification to the existing cell, it is also possible to obtain high-resolution spectra for compounds with masses of ca. 14,000 Da and lower. Utilizing the five-plate trapping method, a bovine insulin spectrum with a resolving power of 20,000 was obtained. It is not yet possible to obtain higher resolution for the higher mass proteins. The reasons for this difficulty are currently being investigated.

High-mass analysis using quadrupolar excitation/ion cooling in a Fourier transform mass spectrometer

Quadrupolar axialization has been applied to matrix-assisted laser desorption/ionization Fourier transform mass spectrometric analysis of singly charged polymer and protein ions. When a quadrupolar excitation is applied in the presence of argon collision gas, ions are driven to the center of the cell, where they can traverse the conductance limit and be detected in the lower pressure analyzer cell of a dual cell instrument. It is shown that single frequency quadrupolar excitation permits highly selective detection of single oligomers of poly(ethylene glycol) 6000. Resolution enhancement is demonstrated for bovine insulin and ubiquitin, where spectra with resolving powers of 92,000 and 25,000, respectively, are obtained. Finally, quadrupolar axialization is demonstrated to be effective for molecules with masses as large as 13,000 Da.

Analysis of hydrocarbon dendrimers by laser desorption time-of-flight and fourier transform mass spectrometry

The first mass spectrometric analysis of a new class of hydrocarbon dendrimers that result from a convergent synthetic approach is reported. Molecular weights of a series of phenylacetylene dendrimers (715 to 14776 u MW) are characterized by ultraviolet matrix-assisted laser desorption (MALDltime-of-flight (TOF) mass spectrometry, direct and silver chemical ionization infrared laser desorption Fourier transform mass spectrometry @I'MSl, and ultraviolet matrix-assisted laser desorption silver chemical ionization Fourier transform mass spectromeby. New matrices and techniques were developed to facilitate analysis of the dendrimers. Mass measurement accuracies between 10 and 25 ppm are obtained for molecular ion species of the five dendrimers analyzed. Laser desorption time-of-flight and FI'MS techniques are shown to be complementary, with FTMS providing high mass resolution (27,000-67,000 resolving power) and accuracy for lower mass dendrimers (10-14 ppm) and MALD TOF yielding the highest resolution (1100 resolving power) and accuracy (25 ppm) for the largest dendrimer. These results are consistent with proposed empirical formulas.

Structure of the novel heme adduct formed during the reaction of human hemoglobin with BrCCl3 in red cell lysates

It was previously shown that the reductive debromination of BrCCl3 to trichloromethyl radical by human hemoglobin leads to formation of dissociable altered heme products, two of which are identical to those formed from myoglobin and one which is novel. In this study, we have elucidated the structure of this novel adduct with the use of mass spectrometry, as well as 1H and 13C NMR as a substitution product of a -C(Cl) = CCl2 moiety for a beta-hydrogen atom on the prosthetic heme's ring I vinyl group. From studies with the use of 13C-enriched BrCCl3, it was determined that the added carbon atoms were derived from 2 eq of BrCCl3. A mechanism that involves multiple reductive events and a radical cation heme intermediate is proposed. Consistent with this mechanism, cellular reductants were found to selectively enhance the amount of this novel dissociable heme adduct. These studies reveal fine differences between myoglobin and hemoglobin in the accessibility of reactive intermediates to the ring I vinyl group, as well as the potential importance of cellular reductants on the course of heme alteration.

Ultrahigh resolution matrix-assisted laser desorption/ionization of small proteins by Fourier transform mass spectrometry

Recent research has demonstrated that matrix-assisted laser desorption/ionization (MALDI) is feasible for Fourier transform mass spectrometric analysis of biomolecules with masses in excess of 50,000 Da. Here, the effects of electrostatic deceleration times and laser energy upon mass resolution are reported. It is demonstrated that optimum deceleration times for singly-charged MALDI-generated protein ions ranging in mass from 2627 to 29,000 Da are a linear function of m1/2 when a 9.5-V decelerating potential is used. Furthermore, higher resolution is obtained with laser fluences close to the threshold for MALDI. Slow metastable decay of molecular ions in the absence of co-matrix is demonstrated for melittin and bovine insulin. It appears that the resolution enhancing effect of co-matrix may result from slowing molecular ion unimolecular decomposition rates sufficiently to allow infrared emission to compete with metastable decay, thus providing the requisite population of long-lived ions for high mass resolution. A spectrum of bovine insulin molecular ion with mass resolution of 30,000 is presented, together with several spectra of lower mass proteins with mass resolution in excess of 100,000. Detection of a doubly-charged carbonic anhydrase trimer ion with a mass of 87,000 Da is reported.

Silver nitrate chemical ionization for analysis of hydrocarbon polymers by laser desorption fourier transform mass spectrometry

Addition of silver nitrate to nonpolar hydrocarbon polymer solutions prior to their analysis by laser desorption Fourier transform mass spectrometry is shown to allow efficient silver ion chemical ionization. High-quality mass spectra are thus obtained for polymers, such as polystyrene, polyisoprene, polybutadiene, and polyethylene, that previously failed to yield useful mass spectra using conventional laser desorption. Accurate mass measurement experiments and isotopic ratios verify that the spectra are those of silver-attached oligomer ion distributions. Mass measurement errors for complete oligomer distributions average between 3 and 12 ppm for oligomers with masses between 400 and 6000 D whereas unit mass resolution is maintained throughout the entire spectral range.

Investigation of a "screened" electrostatic ion trap for analysis of high mass molecules by fourier transform mass spectrometry

With the recent adaptation of matrix-assisted laser desorption/ionization (MALDI) of large biomolecules and polymers to Fourier transform mass spectrometric analysis, it is of interest to explore the possible advantages of using a "screened" electrostatic ion trapping technique. It is demonstrated that the observed rate of change of ion cyclotron resonance frequency with trapping potential is in excellent agreement with theory, being independent of mass and charge, in the mass range from 1185 to just under 17,000 Da. When a screened cubic trap is used in a ca. 7-T magnetic field, the electrical potential within the trap is effectively reduced, and ion cyclotron resonance frequency shifts as a function of trapping potential are decreased by a factor of 25. There is no evidence of significant improvement in mass resolution with this trap design, except when higher trapping potentials are compared. In a 9.7-V screened trap measurement, a bovine insulin spectrum with an average resolution of 10,000 is obtained. Comparable mass resolution under conventional trapping conditions could not be obtained for trapping potentials greater than 1.2 V. It is evident from this study that use of the screened trap technique could offer advantages for MALDI-Fourier transform mass spectrometry.

Comparative study of photodissociation and surface-induced dissociation by laser desorption Fourier transform mass spectrometry

Photodissociation (PD) and surface-induced dissociation (SID) are compared for structural analysis of several nonvolatile compounds analyzed by laser desorption Fourier transform mass spectrometry (LD/FTMS). SID and PD of a porphyrin and two metalloporphyrins were investigated using a variety of experimental conditions. Optimum structural information is obtained from PD when parent ions are irradiated for relatively long times (10-30 s) using 575-nm radiation and short times (0.5-1 s) using 308- or 388-nm radiation. Shorter irradiation times in the visible region resulted in less efficient production of structurally significant product ions, while longer times in the ultraviolet region produced more nonspecific fragment ions, apparently at the expense of more structurally significant fragment ions. SID conversion efficiencies for the porphyrins are estimated for collision energies from 25 to 360 eV, with maximum conversion efficiency found using 62- and 115-eV collision energies for the two porphyrins studied. Results from a concurrent study on the combined use of PD and SID for MS/MS/MS are discussed in the context of these results. The MS3 ion spectra generated by the two dissociation techniques differ more significantly than MS2 product ion spectra. These data suggest some general guidelines for MSn studies of nonvolatile compounds analyzed by LD/FTMS, employing PD and SID for ion activation.

Energy deposition in iron pentacarbonyl ions undergoing surface-induced dissociation in a Fourier transform mass spectrometer

Internal energy deposition into iron pentacarbonyl positive ions undergoing surface-induced dissociation (SID) in a Fourier transform mass spectrometer is estimated from the abundances and known critical energies of the product fragment ions. A narrow energy distribution, comparable to that reported in earlier BQ and tandem quadrupole SID studies of the same compound, is observed. As judged by the ratio of fragment ions to incident parent ions observed, SID of iron pentacarbonyl in the 3 T Fourier transform mass spectrometer is more efficient, but results in lower conversion of laboratory to internal energy. This may be a result of the more shallow collision incidence angle employed in the Fourier transform mass spectrometer measurements (a few degrees), which contrasts with the 32-60° collision angles used in the earlier BQ and tandem quadrupole mass spectrometry studies. Collision-induced dissociation with He under single collision conditions is also reported, Not unexpectedly, conversion of kinetic to internal energy was lower than found in a previous Fourier transform mass spectrometer study of the iron pentacarbonyl cation employing argon as collision gas under multiple collision conditions.

Surface-induced dissociation by Fourier transform mass spectrometry

A detailed procedure for performing surface-induced dissociation (SID) of ions in a dual-cell Fourier transform mass spectrometer is described. It is shown that the technique is applicable to both electron ionization and laser desorption measurements. SID spectra of perfluorotri-n-butylamine, anthracene, (5,10,15,20-tetraphenyl-21H,23H-prophinato)-iron(III) chloride, and [5,10,15,20-tetrakis(2,6-dibromo-phenyl)-21H,23H-prophina to]iron(III) chloride are presented. Conversion efficiencies of molecular ions between 1% and 30% are obtained. It is concluded the method holds promise for dissociation of high mass laser-desorbed ions.

Analysis of copolymers by laser desorption fourier transform mass spectrometry

A series of methylmethacylate/butylacrylate, methylmethacrylate/styrene, and poly-(ethylene glycol)/poly(propylene glycol) copolymers were analyzed by laser desorption Fourier transform mass spectrometry. Molecular weight distributions and overall copolymer compositions were determined. Typical spectra arise from a distribution of alkali metal cationized oligomer ions reflecting copolymer composition. Number- and weight-average molecular weights were calculated for each category of copolymer series as well as for overall copolymer mixtures. In addition, mass spectra were analyzed to estimate copolymer monomer contributions; these results were compared with manufacturer free mix ratios as a test of the relative accuracy of the analysis. Although a dual-cell Fourier transform mass spectrometer was used, all copolymer analyses reported were carried out as single (source) cell measurements to ensure that no mass discrimination would occur. A series of Fourier transform mass spectrometry dual-cell experiments also were performed to evaluate the effect of ion transfer time on molecular weight averages and compositions. As expected, mass discrimination occurred when short transfer times and analyzer cell detection were employed. Under these conditions, molecular weight averages varied by more than 50% from values obtained in the single-cell measurements.

Photodissociation of laser-desorbed ions as a structure determination tool

Laser desorption Fourier transform mass spectrometry (LD/FTMS) of porphyrins, metalloporphyrins, and alkaloids is used to investigate XeCl excimer laser photodissociation of trapped ions as an alternative to collision-induced dissociation for structure analysis purposes. It is shown that the presence of an appropriate metal enhances photodissociation and that in situ metal attachment during the laser desorption event may be a useful analytical strategy. Iron-, manganese-, and chromium-attached species are examined in order to assess the effect of metal upon the propensity for photodissociation with 308-nm excitation.

Analysis of antimycin A by reversed-phase liquid chromatography/nuclear magnetic resonance spectrometry

A mixture of closely related streptomyces fermentation products, antimycin A, is separated, and the components are identified by using reversed-phase high-performance liquid chromatography with directly linked 400-MHz proton nuclear magnetic resonance detection. Analyses of mixtures of three amino acids, alanine, glycine, and valine, are used to determine optimal measurement conditions. Sensitivity increases of as much as a factor of 3 are achieved, at the expense of some loss in chromatographic resolution, by use of an 80-microL NMR cell, instead of a smaller 14-microL cell. Analysis of the antimycin A mixture, using the optimal analytical high-performance liquid chromatography/nuclear magnetic resonance conditions, reveals it to consist of at least 10 closely related components.

Laser desorption/Fourier transform mass spectrometry of steroids

Mass spectra of six representative underivatized steroids and three parent hydrocarbons were obtained using laser desorption/Fourier transform (LD/FT) mass spectrometry. The carbonyl steroids, with the exception of aldosterone, yielded abundant [M + H]+ ions. For cholesterol, a major fragment ion was that corresponding to dehydration. The hydrocarbons produced [M + H]+, M+ and [M - H]+ ions, in addition to expected alkyl cleavage ions including those resulting from methyl loss. The LD/FT mass spectra of all were qualitatively similar to electron ionization spectra, but showed somewhat less fragmentation.

Laser desorption/Fourier transform mass spectra of glycoalkaloids and steroid glycosides

Positive- and negative-ion mass spectra of five glycoconjugates were obtained using laser desorption/Fourier transform mass spectrometry. These were the glycoalkaloids alpha-solanine and alpha-tomatine and the steroid glycosides gitoxin, lanatoside A and digitonin. Doping with KCl yielded both potassium- and chloride-attachment ions. Few fragment ions were observed for these species, with the exception of digitonin, although the negative-ion spectra showed relatively more fragmentation than the positive-ion spectra. All major fragments appeared to arise from losses of sugar groups due to cleavages at the glycosidic linkages. This contrasted sharply with the behavior of the malto-oligosaccharides studied in this laboratory.

Laser desorption Fourier transform mass spectra of malto-oligosaccharides

Laser desorption mass spectra of malto-oligomers, including starch, have been obtained using Fourier transform mass spectrometry. Fragmentations of these oligomers have been examined after doping with metal salts to obtain cation-attachment ions. Doping starch with NaCl, KBr and Ag2O results in analogous cation-attachment oligosaccharide fragment ions for all three metal ions. A distinct and unusual fragmentation pattern is observed for the larger oligomers.