Non-volatile residue (NVR) or non-volatile matter is the soluble, suspended, or particulate material remaining following evaporation of the volatile solvent which contains the material. Analysis of nonvolatile content can be used to determine the purity of a solvent as well as to measure the amount of micro-contamination on the surface of an item or component (i.e. its cleanliness).

NVR determination involves evaporating the organic solvent, then measuring the residue gravimetrically using a sensitive balance and carefully-tared weighing vessels. This type of analysis is fundamental in the fields of water quality and environmental testing, as well as in the chemical, pharmaceutical, medical device and electronic industries.

Determination of non-volatile matter is an important quality assurance test for products in which the presence of any residue may affect product quality and performance, or process efficiency. The NVR test is useful to control manufacturing processes and ensure compliance with specifications. For example:

• Ensuring cleanliness of medical equipment, especially for implantable medical devices
• Minimizing micro-contamination on the components of computer hard disk drives
• Measuring quality of products such as paint, varnish, lacquer and related products
• Upholding the limits for toxic solvent migration in plastic food packaging

Why Accurate Weighing is Important

Weighing non volatile residue is a differential weighing application. The amount of non volatile residue collected is typically very small. When the solvent is very pure, or when very little contamination is present, a large volume needs to be used to provide even a small quantity of the residue. Measurement of such small quantities requires a highly accurate balance; in many cases, the readability required is 10 or 1 µg (5-6 decimal places).

The following method describes the process for determining the amount of NVR on a sample.

Measuring non-volatile residue content is an important quality control technique used in many industries. We understand it can be time-consuming, difficult to perform and prone to error. If you need support with NVR measurement or want advice on which balance to purchase, our team of experts is here to help. Do not hesitate to contact us for assistance.

Handling Small Samples

As the amount of non-volatile residue obtained is very small, a high quality microbalance is necessary to weigh the NVR to the required level of accuracy. Weight is the only measurement required in the determination of NVRs; this limits the sources of errors but makes correct sample handling essential. Using a microbalance requires patience as it can take several seconds for a microbalance to settle. This is accentuated when the non-volatile residue test involves several samples.

User and Environmental Safety

Evaporating organic solvents poses a risk to user safety. Correct procedures should be in place to avoid possible injury from hot liquid. Use of a fume cupboard avoids potential inhalation of the vapours. There are also environmental concerns from the evaporation of solvents. It is recommended that the minimum of solvent possible is used.

Contamination

It is possible for particles and other sources of contamination to be inadvertently introduced from glassware or the surrounding air. A cleanroom is recommended.
The procedure may be carried out in a nitrogen gas environment.

METTLER TOLEDO XPR microbalances are the perfect solution for measuring the small quantities of non-volatile residue obtained in this test.
 

Valid Results Guaranteed

XPR microbalances deliver outstanding weighing performance. The built-in GWP Approved quality assurance function actively monitors the balance to confirm it is safe to weigh: tests, adjustments, levelling and settings must all be in order. The green StatusLight™ indicates ‘go’ so you can be sure your results will be valid.
 

Safe Operation

The new draft shield provides easy access to the weighing pan; all parts are easily removed for cleaning. Cross-contamination risk is reduced thanks to the SmartSens infrared sensors which enable you to open and close the draft shield with the wave of a hand – processes are much more ergonomic too.
 

Efficient Processes

The capacitive touchscreen allows you to “swipe” through settings and methods. The method library saves time and provides higher process security. The built-in notepad automatically records all task parameters and results, eliminating manual transcription. Results are easily transferred to a PC for safe storage and further evaluation: simply use a cable to connect the balance to the PC, which can be located outside your fume cupboard, or just use the USB port to save and transfer data.
 

Space-saving Design

The XPR has the smallest footprint of any microbalance on the market and has the added convenience of being able to place the main terminal wherever it is most easily accessible – even outside your safety cabinet.

Excellence Level microbalances are perfect for non-volatile residue analysis where measurement of extremely small quantities requires use of a highly accurate balance; in many cases, the readability required is 10 or 1 µg (5-6 decimal places). Watch video and learn what are the benefits of using METTLER TOLEDO equipment for NVR analysis.

Maximize the quality of your weighing results within ten steps and make the delicate process of micro-weighing more efficient.

Connect your METTLER TOLEDO microbalance to LabX laboratory software for the highest level of automated data handling and process security.
The NVR method is set up in LabX according to your precise needs and SOP requirements. The application is started directly from the balance touchscreen and users simply follow the onscreen instructions. LabX automatically takes care of all data and calculations, and all information is saved securely in a centralized database.

You benefit from fully tracked samples, automatic data handling, customized reports and increased productivity.