1.1 GPC-50

Introduction

Applications

The new, enhanced PL-GPC 50 is a high resolution, cost effective integrated GPC system designed for operation from ambient to 50°C. The standard system comprises a precision solvent delivery system, a sample injection system, a high performance differential refractive index detector and a column oven, with fully integrated software control. For maximum flexibility and applicability, a choice of system enhancements is also available, modules for:

• UV detection
• Viscosity detection
• Online degasser
• Autosampler

The enhanced PL-GPC 50 platform enables fully integrated triple detection, including refractive index (PL-RI), viscometer (PL-BV 400RT) and light scattering (PL-LS) detectors. Additional detector options (UV and ELSD) and combinations are available, supported with integrated software control and processing.

Designed for Ease of Use

The PL-GPC 50 features onboard PC-based system control and Cirrus™ data acquisition and analysis software - everything you need to get up and running in one integrated package. The simplicity of the PL-GPC 50 design and the intuitive interface make it extremely easy to operate. This, combined with high performance and reliability, makes the PL-GPC 50 the ideal choice for any laboratory.

Advantages Over A Modular System

The PL-GPC 50 integrated system has several advantages over a modular system in that it is easier to operate and control, and is highly stable and very robust to changes in ambient conditions. To show the performance of the system, shown below is an overlay comparison of the baseline drift of the PL-GPC 50 at 40°C and a typical modular system at room temperature. The drift of the PL-GPC 50 is less than 1mV in 4 minutes compared to a drift of nearly 3mV on the modular system resulting from changes in the ambient temperature of the laboratory.

Versatility and Performance

For optimized performance, the system is designed to significantly reduce extra column dispersion and band broadening effects, thereby maximizing resolution and accuracy for the GPC separation. The PL-GPC 50 can accommodate up to four regular 300mm GPC columns with easy access for column exchange via the hinged front panel. The RI detector exhibits both high sensitivity and excellent baseline stability for a wide variety of organic GPC and aqueous based eluents.

Excellent Reproducibility

The flow rate precision of the solvent delivery system is fundamental to achieving the most reliable GPC data.
The PL-GPC 50 delivers flow reproducibility of better than 0.07%, resulting in repeatable calibration curves and accurately calculated polymer molecular weight data.

Overlay of five GPC calibration curves generated from five separate injections of each polystyrene standard
(EasiCal PS-1 calibrants)

Overlay of molecular weight distribution plots for five injections of a commercial polystyrene sample

Overlay of molecular weight distribution plots for five injections of a commercial polycarbonate sample

1.2 PL-GPC 120 & PL-GPC 220 Systems

Introduction

Polymer Laboratories' has designed the PL-GPC 120 system specifically for GPC/SEC analyses between 30-120°C, where elevated temperature is required to reduce the eluent viscosity rather than to dissolve the sample. Offering either manual injection as standard or an external autosampler option, the PL-GPC 120 gives improved resolution and reproducibility compared to conventional modular GPC systems.

PL's PL-GPC 220 integrated GPC/SEC system has been developed from PL's highly successful PL-GPC210 instrument. The PL-GPC 220 provides full PC control and unbeatable reproducibility for any GPC/SEC application, across the entire operating range. The flexible PL-GPC 220 is designed to run almost all polymer, solvent and temperature combinations, with full automation, from 30 to 220°C.

Key Advantages of the PL-GPC 120 & PL-GPC 220

• Full PC Control
• HP 1100 Series Isocratic Pump
• Even Greater RI Sensitivity and Stability
• Easy Access Oven with Uniform Temperature Distribution
• Retro or Factory Installed MW Sensitive Detectors
• Dual Zone Heated Autosampler (PL-GPC 220 only)
• Thermostated Solvent Delivery Module (PL-GPC 220 only)
• Multiple Safety Features
• Easy Interfacing to Other Techniques (PL-GPC 220)

PL-GPC 120	PL-GPC 220

1.3 PL-ELS 2100

Evaporative Light Scattering Detector (ELSD)

• Universal detection for non-volatile and semi-volatile compounds
• Ambient operation in 100% water
• High sensitivity
• Rapid equilibration
• Eluent flow up to 5ml/min
• Easy to use software control
• Small footprint
• Easy connection to any HPLC system

The PL-ELS 2100 surpasses other ELSDs for low temperature HPLC applications with semi-volatile compounds. Its innovative design represents the next generation of ELSD technology, providing optimum performance across a diverse range of HPLC applications. The PL-ELS 2100's unique gas control permits evaporation of high boiling solvents at very low temperatures, for example, 100% water at a flow rate of 5ml/min can be removed at 30°C. The novel design of the PL-ELS 2100 provides superior performance compared to competitors' detectors for the analysis of semi-volatile compounds.

Features

• Enhanced Signal Processing
• Low Temperature Operation
• DMSO Transparency
• Superior Peak Shape
• Gas Shut Off

Enhanced Signal Processing
The PL-ELS 2100 features:

1. Programmable gain factor: defines the PMT gain factor to control full scale sensitivity
2. Digitally programmable time constant: defines the time constant of the PL-ELS 2100
3. LED intensity: controls the sensitivity of the PL-ELS 2100 (component peak(s) exceeding the dynamic range of the detector can brought on-scale by reducing the LED intensity)

Low Temperature Operation
The effect of operating temperature on the response of semi-volatile compounds is clearly illustrated in Figure 1. In this analysis, peak 2, indapamide, is essentially non-volatile but the remaining three peaks (acetanilide, ibuprofen and dibutylphthalate) are semi-volatile to different degrees. With the nebulizer and evaporator running at the same temperature, 50°C, peak 2 gives a large response but the other more volatile components give very poor peak response, due to loss through evaporation. As the nebulizer/evaporator temperatures are reduced to ambient temperature (nominally 26°C), the detector shows much better recovery of the semi-volatile components with no deterioration in baseline stability.

DMSO Transparency
In high throughput screening (HTS), DMSO is not removed at the low evaporator temperatures required to detect volatile compounds. Consequently, the resulting DMSO peak can mask potential drug compounds that elute very quickly. Normally, to overcome this, DMSO is evaporated off the sample and the sample is subsequently dissolved in an appropriate solvent. This time-consuming step can create a 'bottleneck' in sample throughput.

Traditionally, the removal of DMSO in HTS to allow ELS detection of fast eluting compounds is facilitated by increasing the evaporator temperature. Depending on the manufacturer, the temperature when this occurs can vary from ca. 40°C to 90°C. However, increasing evaporator temperature decreases the response of volatile compounds. Such an approach is not required with the PL-ELS 2100 due to its unique patented gas control.

In the PL-ELS 2100, the addition of a carefully controlled stream of gas during the evaporation step enables complete removal of the eluent to take place without increasing detector temperature. The benefits of this unique design are highlighted in Figure 2 where DMSO (peak 2) is completely removed at 30°C, by increasing the evaporator gas flow, without any loss of the volatile acetanilide (peak 5).

KEY
1. Adenosine monophosphate
2. DMSO
3. Acetaminophen
4. Caffeine
5. Acetanilide
6. Phenacetin

Superior Peak Shape
The PL-ELS 2100 features a short evaporator tube that guarantees an extremely low sweep volume and minimum peak dispersion. The result is that the PL-ELS 2100 delivers maximum resolution from your separation, especially important for work with small column volumes.

Column: Hypersil BDS C 18 5µm, 50x2.1mm
Eluent: 30% Water : 70% ACN
Flow Rate: 0.1-0.5ml/min
Inj Vol: 10µl
Evap Temp: 40°C
Detector: PL-ELS 2100 (neb=50°C, evap=50°C, gas=1.6 SLM)

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