Perkin Elmer HGA-600/ HGA-700 Graphite Furnaces

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1 Proudly serving laboratories worldwide since 1979 CALL for Refurbished & Certified Lab Equipment Perkin Elmer HGA-600/ HGA-700 Graphite Furnaces The HGA-600 and HGA-700 are fully computer-controlled systems for graphite furnace atomic absorption. The HGA-600 Graphite Furnace can be used with the Models 3100/3110/3300 and 5100 PC Atomic Absorption Spectrometers. The HGA-700 Graphite Furnace is designed for the Models 1100B/2100 and 4100 Atomic Absorption Spectrometers. Some of the key benefits you can obtain with these graphite furnace include: Fully computer-controlled furnace and autosampler, permitting operation of the complete system via video screen, key-board and mouse. Individual methods library and direct automatic system set-up by methods retrieval. High resolution graphics display for more convenient and better methods development. Approved Perkin-Elmer HGA furnace design for highest analytical performance. STPF concept for almost interference-free determinations. What does a computer control bring to you? Graphite furnace AAS demands great flexibility in creating analytical programs. Since a large variety of samples often with very complex matrices have to be analyzed by this technique, very different analytical programs for drying, thermal pretreatment and atomization have been applied. For programming the HGA-600/700 a special program page is available on the computer s or spectrometer s video screen. There you can create analytical programs with up to 12 different steps. Each of these steps can be programmed with tube temperature (up to 3000 C), ramp and hold times, internal gas flow rate, change over to an alternate gas, and start of the read cycle. All parameters, including the temperature control for the maximum power heating and all Page 1 of 6

2 parameters for the AS-60/70 Autosampler, are entered via the keyboard, mouse pointer and video screen. Automatic instrument calibration with up to 8 reference solutions or with up to 8 additions (when using the technique of standard additions) is as easy to perform with the AS-60/70 as automatic reslope, automatic matrix modification or automatic multi-injections (preconcentration of the analyte element in the graphite tube or the automated sample injection into the pre-heated graphite tube. Beyond all this it s a well-known fact that an autosampler in graphite furnace AAS strongly improves analytical precision in comparison to manual pipeting. The simultaneous, highly resolved graphic display of the analyte and the background signals on the video screen provides you with a means of reliable monitoring of the determination and simplifies methods development. You can store proven analytical methods, i.e. complete parameter programs, on hard or floppy disk. These programs also include, of course, all parameters for the AS-60 Autosampler when connected. To use one of these methods again, you simply retrieve it and all parameters stored for that method are automatically set up. How must the furnace be designed? In a graphite furnace system, optimum sample pretreatment and atomization are a must for maximum sensitivity, minimum chemical interferences, and low non-specific background attenuation. This can only be achieved with a well-designed furnace assembly. The HGA Graphite Furnace assembly of the HGA-600/700 is sealed at both ends with easily removable quartz windows. Such a closed furnace design is a prerequisite for controlled and reproducible internal analytical conditions. The graphite contact cylinders used in the HGA Furnace Assembly have a special fit. Electrical resistances at the contact faces, which might affect the analytical performance, are thus reduced to a minimum. The interface from metal to graphite remains cold, due to efficient cooling, so that no carbide formation will occur at the contact faces. The two graphite contacts are shaped so that they completely encase the graphite tube. Thus the graphite tube is located in a defined environment, which ensures uniform radiation conditions. To obtain best analytical results the inert gas is separated in the Perkin-Elmer HGA furnaces into an external protective gas steam around the graphite tube and an internal purging gas stream through the graphite tube. The external gas stream enters the space between the contact cylinders and the graphite tube via holes in the graphite cylinders and flows continuously around the graphite tube in order to prevent the entrance of outside air and thus the incineration of the tube. The internal purging gas stream flows from the ends of the graphite tube to its center and then leaves the tube through the central sample introduction hole. This gas stream Page 2 of 6

3 effectively removes matrix vapors formed during drying and thermal pretreatment and gives the furnace unmatched performance for direct analysis of even the most complex samples. With the HGA-600/700 both gas streams are computer controlled. This provides maxiumum flexibility for obtaining best analytical results. The defined Gas Stop during automization is one of the major components in the STPF concept for nearly interferencefree determinations. With the HGA Furnace Assembly you get more than a decade of Perkin-Elmer experience and know-how in furnace development, manufacturing and applications. What is the advantage of the alternate gas feature? The HGA-600/700 allows the selection of alternate gas for the internal or external stream during one or more program steps. Alternate gases have been found particularly useful during the thermal pretreatment of some samples. For example, the use of oxygen or air allows a more effective ashing of organic or biological materials and prevents the build-up of residual carbon. When preselected, the HGA-600/700 switches automatically to an alternate gas in the desired program step during a running analysis. Why is the HGA-600/700 a Stabilized Temperature Platform Furnace? Non-spectral interferences, which often lead to strong signal suppression, cannot be removed by any type of background correction. They can, however, be reduced or even be completely eliminated in the furnace itself. Ideal furnace conditions for eliminating non-spectral interferences are only obtained when samples are atomized into an environment that has almost reached thermal equilibrium. Under such conditions the formation of free atoms is optimal, and recombination of atoms to molecules or loss of atoms is effectively avoided. The Perkin-Elmer HGA graphite furnaces offer the unique feature of atomization in a stabilized temperature atmosphere (STPF concept): - Within maximum power heating the graphite tube is heated to the preselected temperature with a speed faster than 2000 C/s. This results in lower atomization temperatures. - The element under study is atomizaed off the L vov platform. Thereby atomization is delayed until the temperature of the inert gas in the graphite tube is in equilibrium with the temperature of the wall. - With the pre-programmable gas stop function, the internal inert gas stream is completely interrupted during atomization and the closed furnace design provides a stabilized gas atmosphere within the graphite tube, avoiding unnecessary cool down of the atom cloud and preventing loss of atoms from the tube. Page 3 of 6

4 - Applying the STPF concept non-spectral interferences are eliminated to such an extend that in many cases time-consuming solvent extraction procedure or the method of additions can be avoided. What about solid sampling? One of the advantages of graphite furnace AAS in comparison to flame AAS is its ability to analyze solid samples directly. This can be advantageous for a variety of samples such as fibers, plastics, hair, tissues, powders, etc, since sample preparation is less time consuming. With the HGA-600/700 two different tools for solid sampling are available: 1.) The HGA Solid Sampling Accessory The essential component of the Perkin-Elmer HGA Solid Sampling Accessory is a small pyrolytically coated graphite cup which is loaded with a solid sample, weighed and then inserted into the graphite tube through an enlarged sampling hole. The main advantages of this solid sampling cup are: - It works like the L vov Platform - Matrix modification can easily be applied using liquid modifiers - Real STPF conditions can now be applied to solid samples, too. 2.) The USS-100 Ultrasonic Sampler With the optional USS-100 Ultrasonic Slurry Sampler you can analyze a wide variety of solid materials directly and automatically. All you need to do is to convert the sample to a suitable powder form, weigh the desired amount, and add solvent. The combination of the USS-100 and HGA-600/700 does the rest. Benefits: - Significantly reduces sample preparation times. - Reduces the potential for contamination during sample preparation. - Easy and direct switch-over from slurry to solution sampling. Can constant cooling improve analytical precision? The HGA-600/700 uses water-cooling to allow the graphite tube to cool down to room temperature quickly between determinations and thus to allow a high sampling frequency. At optimum water temperature (20 to 40 C) and flow (1 to 2 L/min) the HGA should be ready to accept the next sample in about 15 s after the end of the atomization cycle. A special cooling system is available as an accessory for operating the graphite furnace independently of a plumbed water supply. Because of the constant cooling water Page 4 of 6

5 temperature of about 40 C, drying temperatures and times are much more reproducible from day to day within an analysis run when using this cooling system. Condensation of moisture at the furnace, which becomes a problem when too cold tap water is applied, is also avoided with this cooling system. This helps to improve analytical precision and has, in addition, a positive influence on the graphite tube life. Specifications Temperature Range: From ambient to 3000 C programmable in steps of 10 C. Required Inert Gas: Argon or nitrogen. Inlet pressure min. 300 kpa (3 bar) max. 450 kpa (4.5 bar). Maxiumum gas consumption 1200 ml/min (instrument s flow rates are calibrated with argon). Water Coolant: Tap water or filtered industrial water. Water consumption maxiumum 2.5 L/min. A circulatory cooling system is available optionally for cooling the HGA in a closed loop without any water consumption. Program flexibility: Analytical programs with up to 12 steps can be set up. Each of these steps can be programmed with the following parameters: Temperature From ambient to 3000 C in steps of 10 C. Ramp Time Time for heating the graphite tube to the preprogrammed temperature; selectable from 0 s up to 99 s in steps of 1s. With maxiumum power heating is applied with a heating rate of >2000 C/s. When time settings up to 1 s a fast ramp may be set in steps of 0.1 s. Hold Time (isothermal phase) Selectable from 0 s up to 99 s in steps of 1 s. Internal gas flow rate 0 ml/min up to 300 ml/min in steps of 10 ml/min; can be switched over to another type of gas (alternate gas). Start of READ cycle 2 s before the desired program step. Furnace opening and closing: Pneumatically by pushbutton operation Safety functions: The system is protected against operation with opened furnace unit; wrongly transferred data; excessive temperature in the furnace housing; programming mistakes; power failure; too high transformer current; broken graphite tube; too low inert gas pressure. Power requirements: 220 V AC±10%; 50/60 Hz. Power consumption approx. 3.6 KW for a tube temperature of 2700 C. Fuse: 16 A slow blow. Page 5 of 6

6 Dimensions: HGA-600 Power Supply: 42 cm wide, 33 cm high, 60 cm deep; ca. 65 kg. HGA-700 Power supply: 28 cm wide, 49 cm high, 62 cm deep; ca. 55 kg. Furnace assembly 22 cm wide, 25 cm high, 25 cm deep; 6 kg. Proudly serving laboratories worldwide since 1979 CALL for Refurbished & Certified Lab Equipment Page 6 of 6