Analysis of Components in Rubber Compounds Using Mass Spectrometry

1989 ◽  
Vol 62 (3) ◽  
pp. 548-567 ◽  
Author(s):  
Robert P. Lattimer ◽  
Robert E. Harris

Abstract A large number of very successful mass-spectrometric methods have been developed for rubber-compound analysis. The high sensitivity, high specificity, and superb mixture analysis capabilities of modern mass spectrometry make it an invaluable tool in the polymer industry, particularly for qualitative identification of organic additives. In many cases, mass spectrometry can provide unique information that is not available by use of any other technique.

1995 ◽  
Vol 68 (5) ◽  
pp. 783-793 ◽  
Author(s):  
Robert P. Lattimer

Abstract In recent years very effective mass spectrometric methods have been developed for direct polymer compound analysis. The high sensitivity, high specificity, and superb mixture analysis capabilities of modern mass spectrometry make it an invaluable tool in the polymer industry, particularly for qualitative analysis (chemical identification) of organic additives as well as polymeric components. “Survey” mass spectra obtained with soft ionization methods — field ionization (FI-MS) and chemical ionization (CI-MS) — provide diagnostic overviews of chemical composition. The supplemental tandem (MS/MS) and atomic composition (AC-MS) techniques are used to make specific identifications of various organic ingredients. This report describes the direct mass spectrometric analysis of three different elastomer compounds. Organic additives, including curatives, were identified via thermal desorption methods in a commercial EPDM bearing as well as a diene rubber V-belt. The composition of a commercial thermoplastic polyurethane was determined via pyrolysis (Py-CI-MS). These problem-solving examples illustrate the very effective role that mass spectrometry can play in the industrial polymer analysis laboratory.


Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 581 ◽  
Author(s):  
Shuailong Jia ◽  
Runjing Wang ◽  
Kui Wu ◽  
Hongliang Jiang ◽  
Zhifeng Du

The discovery of the anticancer activity of cisplatin and its clinical application has opened a new field for studying metal-coordinated anticancer drugs. Metal-based anticancer drugs, such as cisplatin, can be transported to cells after entering into the human body and form metal–DNA or metal–protein adducts. Then, responding proteins will recognize adducts and form stable complexes. The proteins that were binding with metal-based anticancer drugs were relevant to their mechanism of action. Herein, investigation of the recognition between metal-based anticancer drugs and its binding partners will further our understanding about the pharmacology of cytotoxic anticancer drugs and help optimize the structure of anticancer drugs. The “soft” ionization mass spectrometric methods have many advantages such as high sensitivity and low sample consumption, which are suitable for the analyses of complex biological samples. Thus, MS has become a powerful tool for the identification of proteins binding or responding to metal-based anticancer drugs. In this review, we focused on the mass spectrometry-based quantitative strategy for the identification of proteins specifically responding or binding to metal-based anticancer drugs, ultimately elucidating their mechanism of action.


2021 ◽  
Vol 18 (2) ◽  
pp. 67-87
Author(s):  
Mohamad Fakhri Yaacob ◽  
◽  
Nur Anisah Johari ◽  
Alya Nur Athirah Kamaruzzaman ◽  
Mohd Fakharul Zaman Raja Yahya ◽  
...  

Biofilm represents a major public health concern. It is a highly structured and heterogeneous microbial population that is well protected by a hydrated extracellular matrix. In most cases, the difficulties in combating a wide spectrum of biofilm-associated diseases are due to the presence of dormant cells and differential molecular expression. Proteomics is the large-scale and systematic study of cellular proteome expression at any given time by mass spectrometry. It allows high-sensitivity and high-specificity identification of differentially expressed proteins in the biofilms. Over the past few decades, multiple lines of proteomic works have successfully elucidated various aspects of the biofilm including developmental stages, antimicrobial resistance, and survival mechanisms. However, the heterogeneity of biofilms may contribute to inconsistent proteome expression throughout a proteomic experiment. This is due to the fact that the mature biofilm is often associated with the mixture between monolayer and multilayer biofilms, thick microbial population, and chemical gradient of nutrients. This review highlights the biofilm heterogeneities, the principle of mass spectrometry in proteomics, and the possible strategies for quantitative proteomic analysis of heterogeneous biofilms. It is suggested that isolation of monolayer biofilm, laser capture microdissection, flow cytometry, and subtractive proteome profiling may be considered for an accurate and reliable quantitative proteomics experiment.


2021 ◽  
Vol 21 (10) ◽  
pp. 5036-5043
Author(s):  
Yan Qiao ◽  
Qing-Yun Cai

In this study, we developed a monoclonal antibody against 2,3’,4,5’,6-pentabromodiphenylether (BDE-121) using a synthesized hapten, and established an indirect competitive enzyme-linked immunosorbent assay (IC-ELISA), using gold nanoparticles, to amplify the signal. The monoclonal antibody showed high specificity, with a half inhibitory concentration (IC50) value of 2.78 ng/mL, towards BDE-121. The developed IC-ELISA exhibited high sensitivity and stability as well as good recovery. The intra-assay deviation is below 6.8% and the inter-assay deviations range from 6.5% to 8.7%. The assay of the actual samples was found to be consistent with those of gas chromatography/mass spectrometry (GC/MS).


1988 ◽  
Vol 61 (4) ◽  
pp. 639-657 ◽  
Author(s):  
R. P. Lattimer ◽  
R. E. Harris ◽  
C. K. Rhee ◽  
H-R. Schulten

Abstract Three carbon-black-filled rubber compounds of known composition were analyzed by mass spectrometry. Direct thermal desorption was used with three different methods of ionization (EI, CI, FI). In addition, the three rubbers were examined by FAB-MS (without liquid matrix) as a means for surface desorption/ionization. Extracts of the rubbers were also examined using two different solvents (acetone and acetonitrile). Each extract was examined directly by five methods of ionization (EI, CI, FI, FD, FAB). Of the various vaporization/ionization methods, it appears that FI/FD is the most efficient for identifying typical organic additives in rubber stocks. The analysis can be carried out using either the untreated rubber (FI mode) or else a solvent extract (FD mode). Molecular ions are dominant, which facilitates the characterization of the complex organic additive mixtures that are present in typical compounded rubbers. For samples in which the identity of FD/FI molecular ions is unclear, further analysis using other methods (EI, CI, FAB, MS/MS, GC/MS, LC/MS, high resolution) can be carried out to gain additional information. We conclude that FD and FI yield the most useful information in the shortest period of time. The main difference between the results of this study and those of the volcanizate study is with respect to the curatives. Intact accelerator molecules could readily be observed in the spectra from the uncured stocks, while only accelerator fragments could be observed from the vulcanizates.


The extension of high-sensitivity mass spectrometry to isotope ratios in the range 10 -12 - 10 -15 has been called accelerator mass spectrometry (AMS) because of the use of an additional stage of acceleration that facilitates the removal of molecular interferences and the separation of isobars. In some cases the ultra-high sensitivity is obtained by exploiting the instability of the negative ion of the interfering isobar. It is now possible to measure such isotopes as 14 C at natural abundances as low as one atom in 10 +15 12 C atoms. The ideas behind this significant extension of mass spectrometric techniques will be discussed.


2020 ◽  
Author(s):  
Sawako Suzuki ◽  
Tomoki Minamidate ◽  
Akina Shiga ◽  
Yutarou Ruike ◽  
Kazuki Ishiwata ◽  
...  

Abstract Background: Approximately 60% of adrenocortical carcinomas (ACC) are functional, and Cushing’s syndrome is the most frequent diagnosis that has been revealed to have a particularly poor prognosis. Since 30% of ACC present steroid hormone-producing disorganization, measurement of steroid metabolites in suspected ACC is recommended. Previous reports demonstrated that steroid hormone precursors or their urine metabolites, which can be assessed using liquid chromatography tandem mass spectrometry (LC-MS/MS) or gas chromatography mass spectrometry (GC-MS) respectively, are useful for distinguishing ACC from cortisol-producing adenomas (CPA); however, despite high precision, LC-MS/MS and GC-MS require a highly trained team, are expensive and have limited capacity. Methods: Here, we examined 12 serum steroid metabolites using an immunoassay, which is a more rapid and less costly method than LC-MS/MS, in cortisol-producing ACC and CPA. Further, the correlation of each steroid metabolite to the classification stage and pathological status in ACC was analyzed. Results: Reflecting disorganized steroidogenesis, the immunoassay revealed that all basal levels of steroid precursors were significantly increased in cortisol-producing ACC compared to CPA; in particular, 17-hydroxypregnenolone (glucocorticoid and androgen precursor) and 11-deoxycorticosterone (mineralocorticoid precursor) showed a large area under the ROC curve with high sensitivity and specificity when setting the cut-off at 1.78 ng/ml and 0.4 mg/ml, respectively. Additionally, a combination of androstenedione and DHEAS also showed high specificity with high accuracy. In cortisol-producing ACC, 11-deoxycortisol (glucocorticoid precursor) showed significant positive correlations with predictive prognostic factors used in ENSAT classification, while testosterone showed significant positive correlations to the Ki67-index in both men and women. Conclusion: Less expensive and more widely available RIA and ECLIA may also biochemically distinguish ACC from CPA and may predict the clinicopathological features of ACC.


2020 ◽  
Author(s):  
Sawako Suzuki ◽  
Tomoki Minamidate ◽  
Akina Shiga ◽  
Yutarou Ruike ◽  
Kazuki Ishiwata ◽  
...  

Abstract Background: Approximately 60% of adrenocortical carcinomas (ACC) are functional, and Cushing’s syndrome is the most frequent diagnosis that has been revealed to have a particularly poor prognosis. Since 30% of ACC present steroid hormone-producing disorganization, measurement of steroid metabolites in suspected ACC is recommended. Previous reports demonstrated that steroid hormone precursors or their urine metabolites, which can be assessed using liquid chromatography tandem mass spectrometry (LC-MS/MS) or gas chromatography mass spectrometry (GC-MS) respectively, are useful for distinguishing ACC from cortisol-producing adenomas (CPA); however, despite high precision, LC-MS/MS and GC-MS require a highly trained team, are expensive and have limited capacity. Methods: Here, we examined 12 serum steroid metabolites using an immunoassay, which is a more rapid and less costly method than LC-MS/MS, in cortisol-producing ACC and CPA. Further, the correlation of each steroid metabolite to the classification stage and pathological status in ACC was analyzed. Results: Reflecting disorganized steroidogenesis, the immunoassay revealed that all basal levels of steroid precursors were significantly increased in cortisol-producing ACC compared to CPA; in particular, 17-hydroxypregnenolone (glucocorticoid and androgen precursor ) and 11-deoxycorticosterone (mineralocorticoid precursor) showed a large area under the ROC curve with high sensitivity and specificity when setting the cut-off at 1.78 ng/ml and 0.4 mg/ml, respectively. Additionally, a combination of androstenedione and DHEAS also showed high specificity with high accuracy. In cortisol-producing ACC, 11-deoxycortisol (glucocorticoid precursor) showed significant positive correlations with predictive prognostic factors used in ENSAT classification, while testosterone showed significant positive correlations to the Ki67-index in both men and women.Conclusion: Less expensive and more widely available RIA and ECLIA may also biochemically distinguish ACC from CPA and may predict the clinicopathological features of ACC.


2020 ◽  
Author(s):  
Sawako Suzuki ◽  
Tomoki Minamidate ◽  
Akina Shiga ◽  
Yutarou Ruike ◽  
Kazuki Ishiwata ◽  
...  

Abstract Background: Approximately 60% of adrenocortical carcinomas (ACC) are functional, and Cushing’s syndrome is the most frequent diagnosis that has been revealed to have a particularly poor prognosis. Since 30% of ACC present steroid hormone-producing disorganization, measurement of steroid metabolites in suspected ACC is recommended. Previous reports demonstrated that steroid hormone precursors or their urine metabolites, which can be assessed using liquid chromatography tandem mass spectrometry (LC-MS/MS) or gas chromatography mass spectrometry (GC-MS) respectively, are useful for distinguishing ACC from cortisol-producing adenomas (CPA); however, despite high precision, LC-MS/MS and GC-MS require a highly trained team, are expensive and have limited capacity.Methods: Here, we examined 12 serum steroid metabolites using an immunoassay, which is a more rapid and less costly method than LC-MS/MS, in cortisol-producing ACC and CPA. Further, the correlation of each steroid metabolite to the classification stage and pathological status in ACC was analyzed.Results: Reflecting disorganized steroidogenesis, the immunoassay revealed that all basal levels of steroid precursors were significantly increased in cortisol-producing ACC compared to CPA; in particular, 17-hydroxypregnenolone (glucocorticoid and androgen precursor) and 11-deoxycorticosterone (mineralocorticoid precursor) showed a large area under the ROC curve with high sensitivity and specificity when setting the cut-off at 1.78 ng/ml and 0.4 mg/ml, respectively. Additionally, a combination of androstenedione and DHEAS also showed high specificity with high accuracy. In cortisol-producing ACC, 11-deoxycortisol (glucocorticoid precursor) showed significant positive correlations with predictive prognostic factors used in ENSAT classification, while testosterone showed significant positive correlations to the Ki67-index in both men and women.Conclusion: Less expensive and more widely available RIA and ECLIA may also biochemically distinguish ACC from CPA and may predict the clinicopathological features of ACC.


1990 ◽  
Vol 63 (2) ◽  
pp. 298-307 ◽  
Author(s):  
R. P. Lattimer ◽  
H. Muenster ◽  
H. Budzikiewicz

Abstract In this study, we examined the feasibility of obtaining MS/MS data for organic additives in an uncured rubber compound using several different ionization methods. EI-MS/MS worked well for those additives that gave intense molecular ions (M+·) via this mode of ionization. CI-MS/MS also worked quite well for most additives; the CI MH+ ion currents were generally quite intense and stable over a long period of time. Although fragmentation patterns for MH+ ions are different from those obtained from M+· ions, the fragments are still good diagnostic tools for identifying the original molecule. On the other hand, the FI- and FD-MS/MS analyses of these rubber samples were generally not very satisfactory. This was due to the fact that FI/FD ion currents were too weak and unstable to give daughter-ion spectra with good S/N. It may be concluded that the best way to detect and identify typical organic additives in a compounded rubber is to use a combination of EI- and CI-MS/MS. In this study, intact accelerators were successfully analyzed by MS/MS. The two accelerators in this particular rubber (OBTS and DPG) could be confirmed quite readily by daughter-ion analysis of their intense MH+ ions (CI-MS/MS). Daughter-ion analyses of M+· obtained by either EI, FI or FD modes were not very successful, however. In EI, the difficulty is that molecular ions are quite weak (or even absent) for typical rubber curatives. In FI and FD, on the other hand, a very large proportion of the ion current for accelerators resides in the molecular ion. The difficulty here is that the total ion current produced by FI or FD is rather low. The MS/MS approach has proven to be very useful for direct analysis of organic additives in rubber compounds. The principal advantage in using MS/MS is that more information is available from mixtures than can be obtained by direct analysis using conventional mass spectral methods. The MS/MS technique is also rapid experimentally compared to other techniques for mixture analysis such as GC/MS, LC/MS, or high resolution (AC-MS). Finally, since MS/MS involves two stages of mass analysis, it leads to a great reduction in the chemical noise associated with single-stage mass spectrometry. This leads to the facile confirmation of the presence (or absence) of specific components in a complex mixture.


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