Searching for the Truth: Elemental Analysis–A Powerful but Often Poorly Executed Technique

Proctor, Stephen J.; Lovera, Sergio; Tomich, Anton W.; Lavallo, Vincent

doi:10.1021/acscentsci.2c00761

Cited by 6 publications

(7 citation statements)

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“…The Vario MICRO cube (Elementar) was used to elementally analyze carbon, hydrogen, and sulfur in the PIs with the use of the pyrolysis method. Although elemental analysis data is not fully reliable for synthetic polymer samples, it was reported in the present study for all of the PIs . The Dimension 3100 Nanoscopic IV (Digital Instruments Inc.) was used to perform atomic force microscopy (AFM) measurements on the PIs in the tapping mode.…”

Section: Methodsmentioning

confidence: 92%

“…Although elemental analysis data is not fully reliable for synthetic polymer samples, it was reported in the present study for all of the PIs. 21 The Dimension 3100 Nanoscopic IV (Digital Instruments Inc.) was used to perform atomic force microscopy (AFM) measurements on the PIs in the tapping mode. A Zeiss LSM 780 NLO microscope was used to take the light images.…”

Section: Methodsmentioning

confidence: 99%

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Sulfur-Rich Polyimides Containing Bis(3-(trifluoromethyl)phenyl)thiophene for High-Refractive-Index Applications

et al. 2022

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Three series of sulfur-containing polyimides with the bis(3-(trifluoromethyl)phenyl)thiophene moiety were reported. The synthesis of high-refractive-index polyimides was carried out using a nucleophilic substitution reaction. For that, two new sulfur-containing aromatic amino monomers were developed, one bifunctional and one trifunctional. The monomer and polymer structures were successfully characterized by NMR and Fourier transform infrared (FTIR) spectroscopic methods. Free-standing polyimide films of ∼10 μm were prepared, and they were found to have high thermodynamic stability with T g as high as 257 °C and T d5% above 500 °C. The films were flexible as well as tough with up to 16 ± 7% elongation at break, with a Young’s modulus of 2.6 ± 5 GPa. Indication for melt processability of one of the polyimides was also demonstrated at a temperature of 30 °C above its T g. Thin films with thickness in the nanometer range were coated over modified Si-wafers. Increase in the sulfur and aromatic contents in the polymer backbone resulted in the increase of their refractive index; thus, the polymers synthesized in this work exhibited refractive index as high as 1.76 at 589 nm. The transmittance and birefringence of the polyimides were found to improve by modification in the chemical structure. The tuneable optical properties and good dynamic stability of the polyimides make them potential candidates in optoelectronic applications.

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Section: Methodsmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Sulfur-Rich Polyimides Containing Bis(3-(trifluoromethyl)phenyl)thiophene for High-Refractive-Index Applications

et al. 2022

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“…The weights of these combustion products are used to calculate the combustion of samples. The weight percentage of C and H is determined by infrared detection, whereas N content is measured by thermal conductivity detection [24,47].…”

Section: Elemental Analysis (Ea)mentioning

confidence: 99%

Physicochemical Characterization of Nanobiocomposites

Dmour¹

2022

Biocomposites - Recent Advances [Working Title]

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Nanobiocomposites (NBCs) have many applications in drug delivery, tissue engineering, etc. The need for NBC physicochemical characterization is mandatory before investigating their usefulness in developing drug delivery systems. This chapter will explore the basic and the most recent techniques used in the physicochemical characterization of these biocomposites. Examples of physical properties include morphological properties using microscopy (size, porosity, etc.), particle size analysis and surface charge, powder X-ray diffraction, thermal, mechanical, and rheological properties, etc. Examples of chemical properties include molecular weight determination, solubility and purity assessment, degree of functionalization, and gelling properties, using spectroscopic techniques (UV, MS, NMR, etc.). For each property, the following points will be elucidated: sample preparation, factors affecting the accuracy of the test results, examples of data interpretation from the recently published literature, and test limitations, if any.

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“…The analytical techniques may necessarily change from case to case, but the standards still must be met. Admittedly, the required standards are sometimes difficult to meet, to the chagrin of many authors. − However, it is a requirement that adds considerable value to articles published in Inorganic Chemistry . For one, it ensures some measure of reproducibility, which is one of the most important hallmarks of science.…”

mentioning

confidence: 99%

“…It is likely that a holistic approach to characterization, especially the use of IR and NMR spectroscopies, could have avoided these errors. Perhaps ironically, elemental analysis, a much maligned technique in recent years, − would have also revealed major discrepancies in at least two of these examples. That said, even if the appropriate complementary spectroscopic and physical data are recorded, they still need to be properly weighted and interpreted.…”

mentioning

confidence: 99%

We Need to Talk about New Materials Characterization

et al. 2023

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Metrics & MoreArticle RecommendationsT he range of molecules and materials published in Inorganic Chemistry has increased substantially over the years. In addition to traditional coordination complexes, main-group molecules, and extended solid-state phases, the journal now regularly publishes the synthesis and characterization of metal− organic frameworks (MOFs), atomically precise nanoclusters (APNCs), colloidal nanomaterials, inorganic composites, engineered metalloenzymes, and bioconjugates. This diversification raises an interesting fundamental question: What characterization standards should editors, reviewers, and readers expect for these diverse classes of materials?The Inorganic Chemistry Author Guidelines state that "For all new compounds, evidence adequate to establish both identity and degree of purity (homogeneity) must be provided." The guidelines further add that "Single-crystal X-ray diffraction results are not, in general, acceptable as the only means of characterization of new compounds. Compounds must also be characterized by spectroscopic and analytical methods appropriate for the particular sample or compound. Methods may include elemental analyses to demonstrate bulk composition, NMR spectroscopy, mass spectrometry, infrared spectroscopy, and electronic spectroscopy." Similar guidance is provided in the Organometallics Author Guidelines, which specifically state that "For all new compounds, Organometallics requires a clear statement in the Experimental Section explaining how purity has been established." The guidelines also state that "Single-crystal X-ray diffraction results are not acceptable as the only means of characterization of new compounds." Importantly, for both journals, the methods used to establish the identity and purity of these compounds are not explicitly specified. However, the Author Guidelines do suggest a list of suitable characterization methods, which for sure are biased toward those researchers doing traditional molecular chemistry.Nevertheless, in our opinion, traditional and nontraditional materials alike must meet an equally high standard for evidence of identity and purity. The analytical techniques may necessarily change from case to case, but the standards still must be met. Admittedly, the required standards are sometimes difficult to meet, to the chagrin of many authors. 1−3 However, it is a requirement that adds considerable value to articles published in Inorganic Chemistry. For one, it ensures some measure of reproducibility, which is one of the most important hallmarks of science. In addition, it ensures that the reported data are robust and reliable and can be used to inform the research of other scientists, which American Chemical Society Publications and other publishers are embracing. For example, the ACS has recently developed a Research Data Policy and is rolling out standardized guidelines for reporting data for commonly used

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Searching for the Truth: Elemental Analysis–A Powerful but Often Poorly Executed Technique

Abstract: In this first reaction, the authors express their opinion about the misgivings of CHN combustion analysis. These views are in reaction to the manuscript titled An International Study Evaluating Elemental Analysis.

Cited by 6 publications

References 3 publications

Sulfur-Rich Polyimides Containing Bis(3-(trifluoromethyl)phenyl)thiophene for High-Refractive-Index Applications

Sulfur-Rich Polyimides Containing Bis(3-(trifluoromethyl)phenyl)thiophene for High-Refractive-Index Applications

Physicochemical Characterization of Nanobiocomposites

We Need to Talk about New Materials Characterization

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