GPC-IR®

A solution like no other in High-Temperature GPC/SEC:
Automated, Reliable and Polyolefin-dedicated

GPC-IR® Overview

 

Fully-automated, high-temperature Gel Permeation Chromatography (GPC) / Size Exclusion Chromatography (SEC) system, with highly sensitive Infrared detection for Molar Mass Distribution and Chemical Composition Analysis of Polyolefins

GPC-IR® is a reliable, multiple-detector GPC / SEC system dedicated to the characterization of polyolefins. It incorporates high-stability Infrared (IR) detection, which delivers an outstanding baseline and simultaneous detection of concentration and chemical composition, which adds a new dimension to the GPC analysis. The built-in IR detection provides the most comprehensive characterization of polymers such as High-Density Polyethylene (HDPE), Polypropylene (PP), Low-Density Polyethylene (LDPE), Linear Low-Density Polyethylene (LLDPE), EP copolymers, EVA, EBA and others in the group of polyolefins.

DETECTION:
Three different infrared detectors are available: the classic IR4, which offers a broader spectral range enabling the analysis of the carbonyl group containing copolymers; the IR5, with enhanced sensitivity and stability to measure concentration and chemical composition (SCB/1000TC); and the latest IR6, which offers the same superior performance as the IR5 but with the additional capability of measuring carbonyls group in the band of 1740 cm-1.

Other detectors that can be coupled to the GPC-IR® system are Polymer Char’s four-capillary bridge viscometer and a Multi-Angle Light Scattering for the determination of absolute molar mass and the study of Long-Chain Branching (LCB).

The processing of the data becomes simple and powerful thanks to the GPC One Software , a comprehensive calculations package that integrates all the detectors’ signals.

AUTOMATION:
GPC-IR® automatically performs all of the sample preparation steps, including the initial filling of vials with solvent, and the removal of fillers and gels through an in-line filtration system.  As a result, neither vial transfer nor manual handling of solvent is required throughout the whole analytical process. Another key automation feature implemented to overcome the usual hassles of a high-temperature analysis is a Sample Care protocol that avoids degradation of the sample throughout the whole analytical cycle.

The GPC-IR complies with the ISO 16014-4 and ASTM D6474 methods for High-Temperature GPC measurement.

GPC-IR® Features

Click on each feature to display

The full characterization of polyethylene and polypropylene polymers requires a high-temperature GPC/SEC analysis to be made with specific detectors. GPC-IR® incorporates infrared detectors, demonstrated to be the best option for this kind of polymers. The three models available, IR4, IR5, and IR6 ( can measure both concentration and composition (SCB/1000TC). The triple detector configuration is completed with a four-capillary bridge built-in Viscometer (developed by Polymer Char), and a multi-angle Light Scattering.

GPC/SEC columns are fragile and need to be isolated from temperature changes. For this purpose, GPC-IR® was designed with a dedicated and precise (0.01ºC) oven to hold only the columns. The columns can remain at high-temperature even when the detectors and injector oven need to be cooled down for maintenance tasks.

Every step is automated by GPC-IR®, including: filling of vials with solvent, dissolution of the sample by shaking, injection into the columns, and in-line filtration with backflush cleaning. The only manual requirements are weighing the sample and starting the software. Neither vial transfer nor manual handling of solvents will be needed throughout the entire process.

Sample degradation has been present historically in SEC analyses due to long dissolution times, the use of stirrers, and the presence of oxygen in the vials. However, when using GPC-IR®, sample degradation is significantly minimized thanks to the exact time of dissolution for each sample, gentle shaking, and a nitrogen purge in each vial. Furthermore, the dissolution time can now be shortened due to an efficient and homogeneous heat transfer to the vials.

The GPC One® Calculations Software was developed with the leaders in the industry in order to meet the needs of both, highly experienced users and new ones as well. All of the detectors’ signals are integrated to become the most comprehensive calculations software package available in the market. The GPC One® Software is complemented with built-in customizable reports and statistical quality control tools.

GPC-IR® is designed to easily access each component and facilitate the maintenance tasks when needed.

GPC-IR® Detectors

The following are the detectors available for GPC-IR:

IR4

IR4

The IR4 is the standard Detector integrated by default in all the Polymer Char analytical instruments. IR4 is a dual-wavelength infrared detector, which uses the principle of infrared absorption spectroscopy to measure the concentration and composition in polyolefins.

IR5

IR5

The IR5 is a high sensitivity infrared detector designed for measuring concentration and short-chain branching with superb stability. It incorporates interference filters at five different wavelengths and a thermoelectrically cooled MCT detector with high sensitivity (no liquid Nitrogen required).

IR6

IR6

The IR6 Detector is the latest IR Detector developed by Polymer Char, with the same performance and sensitivity than IR5 Detector and the additional capability of measuring carbonyls group in the band of 1740 cm-1. We recommend the IR6 Detectors for users willing to analyze polyolefin type EVA, EBA, and others with carbonyls group present in the IR band above.

Viscometer

Viscometer

Polymer Char offers a highly sensitive Four-Capillary Differential Bridge Viscometer or a Two-Capillary Relative Viscometer. Both options are an ideal complement to the infrared detection systems implemented in many of the polyolefin characterization instruments, such as GPC-IR or CEF. Viscometer configuration is optimized to achieve a better performance in each technique.

Light Scattering

Light Scattering

The use of a Light Scattering is especially effective in some techniques like GPC/SEC, for instance, when searching for Long Chain Branching results, among others. The GPC-IR design can integrate an external Light Scattering for high-temperature to its software and hardware.

GPC-IR® Software


The high-temperature GPC / SEC technique requires complex data processing as multi-detection methods become widespread. Processing all the detectors signals in a single software environment and a uniform manner is a wish for most users. Tracking the quality of the results given by the instrument is a critical aspect to quickly validate or reject a given analysis. In many cases, it is also necessary to adapt the results and to process the unique company needs.

Polymer Char’s GPC One Software platform has been developed to achieve all those goals, including also updated data acquisition hardware with multiple computer communication interfaces. All the detectors signals are acquired and processed in a single environment in an easy and efficient way, allowing the analysts to have reports customized without going through multiple dedicated software tools for each task.

 

A Statistical Quality Control database has been integrated into the software packages to help to track the performance of the GPC / SEC instrumentation. With this new approach, the performance of all the elements in the system is monitored in a simple and efficient way by defining control charts. This ensures the reliability of the results by alerting of malfunctioning parts and other sources of error as calibration drifts or detector S/N degradation.

Also, it is possible to customize the data processing and calibration procedures as well as the generated reports. Unique protocols that many companies need to follow for implementing specific data corrections or established calculation methods are integrated seamlessly into the standard software.

This package is provided together with Polymer Char’s GPC-IR instrument, but it is also compatible with other vendors’ GPC instruments and detectors through the Data Unit 200 device.

Read more about GPC One Software

GPC-IR® Video

GPC-IR® FAQs


The purpose of a GPC (or SEC) instrument is the analysis of the Molar Mass Distribution, which has been always considered a demanding task due to the requirement of high-temperature operation for the dissolution of polyolefins, and multi-detection methods.

Long-chain branching is measured much the same by all GPC instruments, using a triple detector (concentration, viscosity, and light-scattering). However, what's unique about GPC-IR, is the addition of a fourth detector (Infrared IR4, IR5, or IR6) to measure Short-chain branching and functional groups in polyolefin copolymers along with the molar mass distribution; and also, to analyze very low levels of branching in HDPE pipe resins. Another significant feature that sets apart our system from others is the full automation of the whole sample preparation process. Unlike other HT GPCs available, the user never manipulates solvents manually when operating GPC-IR.

Up to 42 vials can be handled by the GPC-IR autosampler, and they can be dissolved and analyzed without supervision. The total time will depend on the number of columns and the number of injections done per vial. Each injection of each vial will last the programmed analysis time (typically 55 min for a 3-columns set). So, the total time should be NxA, being N the total number of injections, and A the Analysis time. Only the dissolution time of the first sample should be added to this total time, as the dissolution of the injection “i” will be carried out while the sample “i-1” is being analyzed.

16mg of sample are used as a standard for preparing a 2mg/mL solution in the autosampler vial.

1,2,4-Trichlorobenzene (TCB) and Orto-Dichlorobenzene (oDCB) are the most used solvents. To use other solvents please consult Polymer Char first.

The GPC-IR instrument is focused on high-temperature applications (maximum temperature of the column oven: 250ºC, solvent, and columns dependant) but it can be used at room temperature as well.

The only tasks required by the user are weighing the dry samples, and putting them inside the disposable glass vials in the autosampler tray. The rest of the steps are performed by the instrument automatically: filling of vials, sample dissolution, filtration, injection, as well as rinsing of the valves and lines.

Different dissolution times can be selected in the GPC-IR Software for each vial in the run-queue within the same run; therefore, samples with different preparation requirements can be analyzed at once.

Solvents don’t need to be handled at any time; the whole process is fully automated and the instrument performs all the needed steps: vials filling, dissolution, filtration, injection, etc.; under software control.

For a completely automated solvent handling process, Polymer Char also offers separately a trolley to transfer fresh and waste solvent from the reservoir station to the instruments. Visit the Solvent Handling Trolley clicking on the following link:

When using a GPC-IR instrument, no pre-filtration step is required thanks to an in-line filter integrated in the instrument, connected in the high-temperature zone before the injection valve. After each sample, this filter is automatically cleaned in backflush to be ready and clean again for the next injection.

There is no solvent handling or vial transfer at any moment. Vials used throughout the whole process are the same: disposable, glass 10 ml vials.

GPC-IR is specially designed for Polyolefin analysis at high temperature with chlorinated solvents. The instrument with the standard IR detector can be used to analyze all polymers soluble in chlorinated solvents (TCB, o-DCB, perchloroethylene), which have C-H bonds in the backbone. When adapting an external Refractive Index or an ELSD detector, it can also be used with all types of synthetic polymers.

Concentration in Polymer Char Instruments is measured by an integrated Infrared Detector. The GPC-IR instrument can use IR4, IR5, or IR6 to measure both concentration and chemical composition as well. The IR6 Detector is the latest IR Detector developed by Polymer Char with same capabilities and features as the IR5 detector and the additional capability of measuring carbonyls group in the band of 1740 cm-1. For more information, click below on any of the infrared detectors.

Additional detectors can be easily connected to the GPC-IR instrument, such as a capillary viscometer, a Light Scattering, and an external Refractive Index or ELSD detectors.

The GPC-IR injection system has been designed in an innovative way that allows up to 3 injections per vial with no dilution of the sample concentration. Therefore, the reproducibility among the injections is outstanding.

The columns are isolated in a dedicated and high-precision oven, to better protect them from suffering any temperature changes during maintenance tasks.

The columns can be kept continuously at high temperature while performing maintenance tasks in the detectors, filters, or injection loop because these are all located in a dedicated oven, where the temperature can be operated independently from the detectors/injector oven.

After each injection, the data can be accessed and processed through the GPC-IR Software database. Polymer Char’s GPC One is currently the most comprehensive GPC Calculations Software package, because it integrates all of the detectors signals and can be customized to include in-house data-processing procedures. A reporting tool has also been developed, generating reports in Excel adapted to each user's needs.

Yes, the infrared detectors obtain this information and one of the three available is recommended depending on the application. The IR4 has a methyls group sensitive sensor for short-chain branching quantification across the molar mass distribution. The highly sensitive IR5 is recommended when low levels of SCB need to be detected. Finally, the new IR6 detector provides outstanding sensitivity and baseline stability in concentration, composition and carbonyls signals even with low concentration values.

LCB results can be obtained by just using the standard capillary viscometer by comparison of the branched sample intrinsic viscosity with that of a linear reference at every molar mass slice. Nevertheless, more accurate results are produced when using both light scattering and viscometer detectors. SCB information is very useful to correct LCB calculations.

The capacity of the vials is 10mL and on standard conditions, they're filled with 8mL, from which up to three injections can be done. The minimum required is 6mL but the number of injections per vial is reduced.

The standard injection loop is 200uL but it can vary according to the user's needs.

Preventive maintenance is recommended once a year. For more information, click on the link below.

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