Firma:              Carlo Erba

Modell:            HR 5300

Kommentar:    Dokumente engl.

Injection Systems

According to the different Base Unit configurations the following injection systems are available:

Dual capillary injection system

lt includes:

•     Non-vaporizing, septumless cold on-column injector.

     Based on the original design proposed by Grob, this injector is also fitted with a special secondary cooling system (patent No. 4269608) ensuring a complete sample transfer from the syringe to the capillary column.

     This ensures peak area and relative peak area standard deviations below 1.5% and 0.5% respectively.

     Besides this unsurpassed capabilities, the secondary cooling system also permits injection temperatures higher than the sample solvent boiling point therefore preventing the consequences of the flooding effect responsible for peak distortion.

     The injection procedure can be automated by the OC 516 Module which, besides permitting automatic actuation of injector valve and secondary cooling by simple manual syringe insertion, also starts oven temperature programmer and computing integrator.

•     Split-splitless injector

     The design of this capillary injector is based strictly on Grob's original idea.

     lt finds its major field of application for samples which are undilutable or contain arge amounts of heavy by-products.

     lt can be used for either split or splitless injection thus covering a large range of applications. The injector accepts different sized glass liners to meet the requirements imposed by sample volume and to avoid sample-metal contact therefore preserving the nature of the sample. Septum flushing and sample splitting is accomplished by two high precision micrometric valves located in a heated area.

     These valves can be automated for unattended operations with autosamplers. Temperature setting is via keyboard in the range 50°C to 450°C in 1°C increments.

Pneumatic Circuits

Different pneumatic circuits are available for carrier and auxiliary gases. Their composition is strictly related to the different configurations of injection systems and base body compartments fitted into the Base Units.

Carrier Gas

•     Dual independent capillary-designed circuit (5160-00 and 5360-00)

     This circuit features two separate lines for cold on-column and split-splitless injector. Each line includes:

     A high precision bleed and diffusion-proof metal bellow pressure controller (PRV-20/3) for accurate carrier regulation in the range 0 to 2.5 Kg/sq cm.

     The cold on-column injector line is prearranged for direct connection of CP/CF modale for constant pressure/flow operations.

     A metal shut-off valve, particularly useful for prompt leak check and easy flow rate measurement.

     A 60 mm diameter pressure gauge.

•     Dual independent packed-column designed circuit (5320-00 and 5340-00)

     This circuit features two separate lines for packed column injectors.

     Each line includes:

     A high precision bleed and diffusion-proof metal bellow pressure controller (PRV-20/5) for accurate carrier gas regulations in the range 0 to 5 Kg/sq cm.

     A high constancy flow controller.

     A metal shut-off valve.

     A 60 mm diameter pressure gauge.

•     Dual independent packed and capillary-designed circuit (5330-00 and 5380-00) This circuit features two separate lines for packed column and capillary split-splitless injector respectively.

     The line for packed column injector is the same as reported before for 5320-00 and

     5340-00 while that for the capillary injector was described for 5160-00 and 5360-00.

Auxiliary gases

• Two different pneumatic plumbings are available

They consist of:

Three independent lines (5160-00) for hydrogen, air and make-up.

Five independent lines (5320-00, 5330-00, 5340-00, 5360-00 and 5380-00), two for hydrogen, two for air and a make-up.

Each line includes:

A high precision metal diaphragm pressure controller.

A 40 mm diameter pressure gauge.

Column Oven

The Mega Series column oven has been optimized to produce the best possible oven temperature stability and uniformity, fundamental parameters determining accuracy and precision of retention data.

Innovative patented solutions as a new concept in air circulation and a unique fan design permit the column to be immersed in an ideal, thermally quiet zone with a peak to peak temperature variation of less than 0.05% of actual temperature.

This permits low thermal mass capillary columns (flexible fused silica) to be used without any problem of peak distortion or splitting.

This column oven accepts true side by side column installation of both packed and capillary type while still providing a large usable space for different valving configurations.

Technical Data

Temperature range: from 8°C above ambient to 450°C.

Subambient operations down to -70°C are possible through an optionally available N2 cryogenic unit.

Program rates: 0 to 49.9°C/min in 0.1°C/min through three-ramp programmer. Practical upper limit is 50°C/min during initial ballistic programming as may be required by splitless and cold on-column injections. Usable space: mm 320 (h) x 320 (w) x 160 (d).

Multi Function Controller MFC 500

The Multi Function Controller MFC 500 is the simple, easy to understand yet accurate keyboard operated control station of Mega Series. lt includes:

Address keyboard

This section contains all the addresses of the four zones the MFC 500 is divided into. They are: injector one, injector two, oven and detector base body compartments. lt also includes "ACTUAL TEMP" and LIST keys for prompt visualization of the different temperatures and program parameters respectively.

Numeric keyboard

This keyboard is used to set the values of the individual operating parameters previously selected through the address keyboard.

lt also includes "CHRONO" key to verify or re-adjust carrier gas or fuel gas flows through a digital stopwatch.

Large graphic array

lt includes:

MEMORY display for all set parameters (°C, °K, MIN, °C/MIN); ACTUAL TEMP display for instant comparison with preset parameters.

TIME ELAPSED for the elapsed time of each program phase.

DATA/CHRONO display for monitoring each parameter entry and stopwatch.

Temperature program array with mobile cursor indicating actual phase in progress.

Trouble shooting and communication signals including "ready" and "alarms" lamps for system status indication or transmission to external devices.

Complete multi-program storage and recall

Facilities are provided to store up to 10 complete programs which can be recalled at any time.

Battery back up

In case of total power failure a battery back up preserves operating parameters stored in memory for 30 days.

Column Iimit protection

Ensures that column maximum temperature will not be exceeded. Setting is independent from temperature program and is realized through digital thumbwheel switches for maximum safety.

Main power breaker

An automatic electromagnetic switch ensures protection of electric and electronic circuitry against current overloads.

General Base Unit Specifications

Physical size

Height: 677 mm, width 779 mm, depth 581 mm

Power requirements

15 amp. dedicated line.

220 VAC ± 10%; 50/60 Hz.

Maximum power consumption: 2200 VA (including injectors and detector base body) during full power heat-up.

FPD

The Flame Photometric Detector (FPD) is based an the measurement of the characteristic radiation emitted by particular excited species during their transition to the ground state. Sulphur- and Phosphorous- containing compounds introduced in a hydrogen rich flame decompose giving rise to excited S2 and HPO'species respectively.

The emission spectrum of S2 shows a maximum intensity at 394 nm while HPO" has a maximum emission at 526 nm. These emissions are isolated by appropriate narrow band optical filters and converted into measurable electrical signals by a photomultiplier tube.

The interference Filter (394 nmforsulphur and 526 nm forphosphorous) is placed between the emission chamber of the FPD and the photomultiplier tube.

As it has been well established there is a quadratic type relationship between the number of sulphur atoms introduced in the flame and the S2 emission, while for phosphorous compounds exists a linear relationship between the HPO" emission and the phosphorous concentration. Consequently, when operating in sulphur mode a suitable linearising system, such as the LIN 500, has to be utilised to get the correct quantitative results.

TECHNICAL SPECIFICATIONS.

Operating Temperature Range          room temperature up to 250 °C in 10 °C steps.

Sulphur filter                            394 nm

Detection limit (diazinon)        Sulphur 1 x 10 ^-11 gS/sec

                                               Phosphorous 5 x 10 ^-13 gP/sec

Selectivity                                S/Hydrocarbon 10 ⁴ gP/Hydrocarbon 10 ⁵

Linear range                            Sulphur 5 x 10 ² (with lineariser)

                                               Phosphorous 10 ³

Multi Function Actuator MFA 515

INTRODUCTION

The Multi Function Actuator Model 515 is the control unit for the Cold-Split-Splitless multi-injector and the Cold Trap device optionally available as an accessory device when using the Thermal Desorption TDAS 5000 or the Headspace HS 250 autosamplers.

The Cold-Split-Splitless injector represent an universal sampling system for high resolution gas chromatography and is based on the CEST patent of 1980 which consists of an auxiliary device fitted to the lower part of the cold on-column injector inside the oven.

This injection system permits the introduction of the liquid sample into a vaporising chamber maintained at a suitable initial temperature to avoid any sample evaporation during the sampling phase. The initial temperature range is within -100°C to + 399°C which is set and controlled from the MFA 515 Control Unit and lt depends on the analytical program set.

The Cold Trap device is extremely useful in thermal desorption analysis and in headspace technique in order to reconcentrate at the end of the fused silica transfer line the vapour components desorbed from the trapping sample tubes or headspace vapours at the inlet of the capillary column when injected Into a SSL injector avoiding undesirable band broadening effects.

This focussing of the sample components is performed at low temperatures on the capillary trap which is cooled by liquid nitrogen and mounted above the gas chromatograph injector (TDAS) or inside the oven immediate below the GC injector (HS 250).