Nitrocellulose Nitrogen Analysis via HPLC Retention Time

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods are inadequate for accurately determining the nitrogen content in unstable, unrefined, or refined nitrocellulose samples, particularly those that are wet or in acid/water, as they require drying and are not suitable for analyzing nitrocellulose with varying nitrogen levels.

Innovation Solution

A method utilizing High Performance Liquid Chromatography (HPLC) to analyze the nitrogen content of nitrocellulose, where the sample is dissolved in a suitable solvent and separated using a reversed phase column with a polar solvent gradient, allowing for accurate measurement through retention time correlation with nitrogen content, even in unstable or unrefined forms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing methods are used to determine nitrogen content in nitrocellulose, then the analysis can be performed on stable, dry samples, but the method is inadequate for unstable, unrefined, or wet samples requiring drying steps that may alter sample composition

Engineering Contradiction:

Improvenitrogen content determination accuracyVSAvoidsample type compatibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention changes the physical state parameter of the sample from requiring dry conditions to accepting wet or acid-containing samples directly. By developing an HPLC method that works with samples in their native wet state, the need for drying steps is eliminated, thereby maintaining sample integrity and expanding adaptability to various sample types including unstable and unrefined nitrocellulose.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If traditional analysis methods are used, then simple sample preparation is possible, but the methods cannot accurately analyze nitrocellulose with varying nitrogen levels including high nitrogen content samples

Engineering Contradiction:

Improvesample preparation simplicityVSAvoidnitrogen content measurement accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The invention replaces traditional mechanical/chemical preparation methods (drying, refining) with an HPLC-based analytical system. This substitution enables accurate measurement of nitrogen content across a wide range including high nitrogen content samples, while maintaining relatively simple sample preparation by dissolving samples in suitable solvents without requiring extensive pretreatment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If drying steps are applied to wet nitrocellulose samples before analysis, then sample stability is improved, but sample composition may be altered and analysis accuracy is reduced

Engineering Contradiction:

Improvesample stabilityVSAvoidnitrogen content determination accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The invention performs preliminary dissolution of the wet nitrocellulose sample in a suitable solvent before HPLC analysis. This preliminary action stabilizes the sample in solution, preventing decomposition that would occur during drying, while preserving the original nitrogen content and composition for accurate measurement.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables precise determination of nitrogen content with an accuracy of ±0.10% or better, providing insights into nitration distribution and uniformity, and distinguishing different nitrogen levels in nitrocellulose samples, including those with high nitrogen content.

Implementation Method 1

The nitrogen content of the sample is determined by comparing the retention time of the sample to a graph of retention time to amount of nitrogen due to the linear correlation of retention time and percent nitrogen substitution

Methodology Applied

Scientific EffectChromatography: Chromatography

Data Source

PatentUS8658428B2Methodology for determination of nitrogen content in nitrocellulose

Publication Date: 2014.02.25 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

In at least one embodiment, the invention is directed to a method of determining the nitrogen content in nitrocellulose by High Performance Liquid Chromatography (HPLC). It is within the scope of the invention for the sample of nitrocellulose to be unstable nitrocellulose, unrefined nitrocellulose, or refined nitrocellulose. The sample of nitrocellulose can wet or dry. A sample of nitrocellulose that is wet can be in acid or in water. Before HPLC, the sample is dissolved in a suitable solvent. The nitrogen content of the sample is determined by comparing the retention time of the sample to a graph of retention time to amount of nitrogen due to the linear correlation of retention time and percent nitrogen substitution.