1-Nitroso Pyridinium: Chemical Characteristics, Analytical Significance, and Research Applications

Understanding the chemical identity of an impurity is an important part of pharmaceutical research and analytical quality control. Even compounds present at very low concentrations may require careful investigation when their presence could affect the purity profile of a drug substance, the interpretation of analytical results, or the assessment of potential risks. Nitroso-containing compounds have received particular attention in pharmaceutical analysis because their chemical structures and possible formation pathways can influence how they are detected and evaluated.

1-Nitroso Pyridinium is a nitrogen-containing chemical compound listed by Chemicea Pharmaceuticals under its impurity standards category. Its chemical name is 1-nitrosopyridin-1-ium, and its listed CAS Registry Number is 45590-75-8. The compound provides a specific chemical identity for researchers investigating nitroso-related chemistry and evaluating analytical reference materials.

For pharmaceutical scientists, the value of studying a compound such as 1-Nitroso Pyridinium lies in understanding its molecular characteristics, establishing reliable identification methods, and selecting suitable reference material for laboratory investigations. These activities help researchers generate more dependable analytical data and maintain traceability throughout impurity-related studies.

This article examines the chemical identity of 1-Nitroso Pyridinium, its relevance to analytical chemistry, the considerations involved in impurity investigation, and the role of reference standards in laboratory quality practices.

1. What Is 1-Nitroso Pyridinium?

1-Nitroso Pyridinium is a nitrogen-containing compound identified by the chemical name 1-nitrosopyridin-1-ium. The name indicates a relationship to the pyridine chemical framework, in which nitrogen is incorporated into a six-membered aromatic ring. The compound is distinguished by its nitroso-related functionality and positively charged pyridinium designation.

Chemicea lists the compound with the molecular formula C5H5N2O and a molecular weight of 109.11 g/mol. These identifiers provide a starting point for laboratory documentation, reference-material selection, and analytical method development.

However, a molecular formula or molecular weight alone cannot confirm the identity of a chemical in an unknown sample. Different compounds can share the same molecular formula, while impurities, degradation products, and related substances may produce overlapping analytical signals under certain conditions.

Researchers should therefore consider multiple sources of evidence when establishing identity. Depending on the study, these may include chromatographic retention behaviour, mass spectrometric data, spectroscopic characterization, and comparison with an appropriately characterized reference material.

The exact chemical identity is especially important when a compound is being investigated for a specific analytical purpose. Similar terminology does not necessarily mean that two substances have identical structures, reactivity, or analytical behaviour.

2. Chemical Information and Identification Details

The available product information provides the following identifiers for 1-Nitroso Pyridinium.

Product name: 1-Nitroso Pyridinium

Chemical name: 1-Nitrosopyridin-1-ium

CAS Number: 45590-75-8

Molecular formula: C5H5N2O

Molecular weight: 109.11 g/mol

Chemicea catalogue number: CP-NIT119

Product category: Impurity Standards

For laboratory use, researchers should verify the identifiers against the current product documentation and the specific requirements of their study. Where available, supporting information such as a certificate of analysis, assigned purity, analytical characterization, storage conditions, and handling instructions should be reviewed before the material is used.

It is also important to distinguish between an identifier used for ordering a reference material and evidence establishing its suitability for a particular analytical method. A reference standard must meet the needs of the intended application, including the required level of characterization and documentation.

3. Understanding Nitroso Chemistry

Nitroso chemistry involves compounds containing a nitrogen–oxygen functional arrangement. The properties of an individual nitroso compound depend on its complete molecular structure, electronic environment, substituents, and surrounding chemical conditions.

Nitrosamines form one important group within the broader chemistry of N-nitroso compounds. Research has demonstrated that their structure and reactivity can affect analytical behaviour and the interpretation of toxicological findings. Nevertheless, not every compound containing a nitroso-related structural feature should automatically be treated as chemically equivalent to a conventional nitrosamine.

This distinction matters when evaluating 1-Nitroso Pyridinium. Its pyridinium designation and reported molecular structure should be considered specifically rather than assuming that its properties are identical to those of familiar pharmaceutical nitrosamine impurities.

The broader literature on N-nitroso chemistry provides useful context for understanding nitrogen–nitrogen bonding, electronic effects, chemical reactivity, and analytical challenges. A detailed review published in the Journal of Organic Chemistry discusses the structural features and reactions of N-nitrosamines, offering background for researchers working with related chemical systems.

For practical laboratory work, the key principle is to establish the structure and behaviour of the individual compound using appropriate evidence. General knowledge about nitroso chemistry can guide an investigation, but compound-specific conclusions require compound-specific data.

4. Why Is Accurate Impurity Identification Important?

Pharmaceutical impurities can originate from several stages of a product's life cycle. These include raw-material handling, synthesis, purification, equipment contact, packaging, and storage. Some substances arise from unintended side reactions, while others may develop through chemical changes under particular processing or storage conditions.

Accurate identification allows analytical scientists to distinguish a genuine impurity from an analytical artefact, a background signal, or an unrelated compound. This distinction becomes especially important when an unexpected peak appears during routine testing or when a method is being developed to investigate a suspected contaminant.

For example, a laboratory may observe an unfamiliar signal during chromatographic analysis. The initial observation establishes that a component may be present, but it does not establish the component's identity. Further investigation may be required to determine its molecular characteristics and relationship to the sample under examination.

A reference material with suitable identity and documentation can support this process by providing a comparison point. Researchers can examine whether the unknown component behaves consistently with the reference material under defined analytical conditions.

Such comparisons should be interpreted carefully. Agreement in a single retention time, for example, is not necessarily sufficient to establish identity. Combining complementary evidence generally provides a more robust basis for a conclusion.

5. Analytical Approaches for Investigating 1-Nitroso Pyridinium

The analytical method selected for a compound should reflect its chemical properties, the sample matrix, the required detection capability, and the purpose of the investigation. No single analytical technique is suitable for every impurity study.

Chromatographic separation

High-performance liquid chromatography (HPLC) and ultra-high-performance liquid chromatography (UHPLC) can be used to separate components in complex mixtures. Depending on the compound and method, chromatographic analysis may help researchers evaluate sample composition, assess separation from related substances, and compare the behaviour of a test sample with that of a reference material.

Method development should consider stationary-phase chemistry, mobile-phase composition, detector compatibility, and the possibility of interactions between the analyte and other sample components.

The retention time of a reference material can provide useful comparative information, but it should not be treated as definitive proof of identity on its own.

Mass spectrometry

Mass spectrometry can provide information about molecular mass and characteristic ion signals. When coupled with liquid chromatography, LC-MS or LC-MS/MS may support the detection and investigation of trace-level compounds, depending on instrument performance and method suitability.

For 1-Nitroso Pyridinium, the reported molecular formula and molecular weight can help guide initial analytical assessment. Researchers must still establish the appropriate ionization behaviour, expected ions, and fragmentation characteristics experimentally or through reliable compound-specific data.

A proposed mass-spectrometric identification should be supported by suitable evidence rather than inferred solely from a nominal mass match.

Spectroscopic characterization

Spectroscopic techniques can provide complementary structural information. Nuclear magnetic resonance (NMR) spectroscopy may help characterize the chemical environment of nuclei within a molecule, while infrared spectroscopy can provide information about selected functional groups.

The suitability of each technique depends on the amount of material available, sample purity, instrument sensitivity, and the chemical behaviour of the compound. For some investigations, several techniques may be needed to build a sufficiently complete picture of molecular identity.

Method verification and validation

An analytical method intended for routine testing should be evaluated against its intended use. Relevant characteristics may include specificity, accuracy, precision, linearity, range, detection capability, quantitation capability, and robustness, as applicable.

The appropriate validation strategy depends on whether the method is used for identification, quantitative determination, impurity profiling, or another purpose. Researchers should document the rationale for the selected approach and ensure that the method performs adequately in the actual sample matrix.

6. The Role of Reference Standards in Impurity Research

Reference standards help laboratories establish a consistent basis for comparing analytical results. Their usefulness depends not only on the compound name but also on identity confirmation, characterization, assigned values where applicable, and supporting documentation.

In impurity research, an appropriate reference material can assist with several activities:

Peak identification: Comparing the analytical behaviour of a sample component with that of a characterized material.

Method development: Evaluating separation conditions and detector response.

Quantitative analysis: Supporting calibration or response assessment when the material's assigned value and intended use are suitable.

Specificity assessment: Investigating whether the target compound can be distinguished from other sample components.

Documentation: Providing a traceable reference point for laboratory records and analytical investigations.

A reference standard should not automatically be assumed to be a certified reference material or a primary standard. Those descriptions require specific evidence and documentation. Laboratories should review the material's stated status and intended use before incorporating it into a validated procedure.

For researchers looking for this compound, Chemicea provides product information for 1-Nitroso Pyridinium reference material. Availability, pack size, and supporting documentation should be confirmed directly with the supplier before ordering.

7. Potential Research Applications

The relevance of 1-Nitroso Pyridinium depends on the scientific question being investigated. Its chemical identity makes it a defined subject for compound-specific analytical work, but its precise role in a particular pharmaceutical process should not be assumed without supporting evidence.

Potential areas of investigation may include:

Analytical reference comparison: Researchers may use appropriately characterized material as a comparison point when investigating a sample suspected of containing the same compound.

Chemical characterization: Laboratory studies may examine its structural characteristics and analytical response using suitable instrumental methods.

Method development: Scientists may assess whether a proposed chromatographic or spectrometric method can detect and distinguish the compound under defined conditions.

Impurity investigation: When supported by a plausible chemical pathway and appropriate evidence, the material may be relevant to an investigation into an unexpected analytical signal or a suspected process-related component.

Research documentation: Consistent chemical identifiers and appropriate reference documentation help researchers maintain clarity across analytical reports, method-development records, and laboratory communications.

These are potential research uses rather than a claim that the compound is routinely found in a particular drug, manufacturing process, or finished pharmaceutical product. Establishing such a connection requires compound-specific evidence.

8. Considerations for Storage, Handling, and Laboratory Quality

Before using a chemical reference material, laboratory personnel should consult its current safety data sheet, product documentation, and supplier-provided storage instructions. Appropriate handling procedures should reflect the substance's documented hazards and the laboratory's chemical safety requirements.

Researchers should avoid assuming that a compound is stable under all routine laboratory conditions. Temperature, light exposure, moisture, solvent compatibility, and storage duration may influence some chemical materials. The relevant stability characteristics should be established from available documentation or appropriate studies.

Good laboratory practice also requires clear labelling, controlled access where necessary, accurate inventory records, and documentation of material use. Where a reference material has an assigned purity or value, its certificate and any relevant uncertainty information should be retained according to the laboratory's quality procedures.

If a material is used to prepare calibration solutions or analytical controls, the preparation details, calculation basis, and applicable storage conditions should be recorded. These practices improve reproducibility and make it easier to investigate differences between analytical runs.

9. Selecting a Suitable 1-Nitroso Pyridinium Reference Material

Selecting a reference material involves more than matching the compound name. Researchers should confirm that the material's identity, documentation, and intended application align with the study's requirements.

Before purchasing, consider the following points:

Identity: Confirm the chemical name, CAS Number, molecular formula, and other available identifiers.

Characterization: Review the available analytical evidence supporting the assigned identity.

Purity information: Check whether a purity value is provided and how it has been determined.

Documentation: Ask whether a certificate of analysis and relevant supporting records are available.

Intended application: Determine whether the material is suitable for qualitative identification, quantitative work, method development, or another purpose.

Storage and stability: Follow the supplier's documented recommendations and verify any relevant limitations.

Supply requirements: Confirm pack size, availability, lead time, and any shipping or handling requirements.

These checks help ensure that the selected material meets the practical and scientific needs of the laboratory. They also reduce the risk of relying on a material whose documentation does not support the intended analytical conclusion.

Chemicea lists 1-Nitroso Pyridinium under its impurity standards portfolio. Researchers can review the product details and submit an enquiry to Chemicea to confirm current availability and obtain information relevant to their intended use.

Conclusion

1-Nitroso Pyridinium is a defined nitrogen-containing compound with the listed chemical name 1-nitrosopyridin-1-ium, CAS Number 45590-75-8, molecular formula C5H5N2O, and molecular weight 109.11 g/mol. These identifiers provide a starting point for chemical documentation and analytical investigation.

Its study should be approached through compound-specific evidence rather than assumptions based on the general behaviour of other nitroso compounds. Chromatographic separation, mass spectrometry, and spectroscopic characterization can contribute complementary information when selected according to the purpose of the investigation.

Reference materials also play an important role in impurity research, provided their identity, characterization, documentation, and suitability are established for the intended application. Careful material selection, sound analytical practice, and complete laboratory records help make impurity investigations more reliable and reproducible.

For product-specific information, researchers can visit Chemicea's 1-Nitroso Pyridinium product page to review the available details and enquire about supply.

Frequently Asked Questions (FAQs)

1. What is 1-Nitroso Pyridinium?

1-Nitroso Pyridinium is a nitrogen-containing chemical compound listed under the chemical name 1-nitrosopyridin-1-ium. It is included in Chemicea's impurity standards category.

2. What is the CAS Number of 1-Nitroso Pyridinium?

The listed CAS Registry Number is 45590-75-8. Researchers should verify the identifier against current product documentation before using it in analytical records.

3. What is the molecular formula of 1-Nitroso Pyridinium?

The molecular formula listed by Chemicea is C5H5N2O, with a reported molecular weight of 109.11 g/mol.

4. How can 1-Nitroso Pyridinium be investigated analytically?

Depending on the study, researchers may consider HPLC or UHPLC, mass spectrometry, and suitable spectroscopic techniques. The final method should be selected and evaluated for the compound, sample matrix, and intended analytical purpose.

5. Why are reference standards used in impurity analysis?

Reference standards provide a defined comparison material that can support compound identification, method development, and quantitative analysis when appropriately characterized and suitable for the intended use.

6. Where can researchers enquire about 1-Nitroso Pyridinium?

Researchers can visit the Chemicea 1-Nitroso Pyridinium product page to review product information and enquire about availability and supporting documentation.