Automatic titrators, TitroMatic

Transcription

1 112 TitroMatic These are the fourth generation of CRISON titrators. CRISON has over 25 years experience in this field and knows that, for certain applications, the performance and cost of large titrator are not always justified. CRISON s TitroMatics are effective and economical titration systems and are extremely useful for routine determinations. There is a TitroMatic model for every application. We have versions for both universal and specific applications. TitroMatic 1S and 2S burettes TitroMatic burettes all have a precision mechanism which is actioned by a stepper motor. In the TitroMatic 1S, the motor stroke is subdivided into 40,000 steps and the mechanism moves the plunger of the syringe. A quick-switch electrovalve controls the in- and outlet of liquid from the syringe. In the TitroMatic 2S, the two syringes are actioned by a single mechanism. Only one reagent is dispensed: the one from the valve which has been activated. The other syringe will return the reagent to the original bottle. When the second reagent is not in frequent use, it is a good idea to free up the corresponding syringe. Peristaltic pumps, depending on version These are integrated in the back panel of the TitroMatic or in a separate module, They can either add auxiliary reagents before or during titration or draw up any remaning sample during the automatic levelling process.

2 113 Main functions Titrations: - Defined End Point (DEP). - Equivalence Point Calculation, EPC. - Reaction Study (RS). Burette calibration. How do they perform titration? DEP Mode, Defined End Point. The instrument adds reagent until a known and previously-selected ph or mv value is attained. Reagent is added continuously. The titrator adapts the flow rate of the titrant reagent according to the area of titration, in order to attain the end point quickly. This is a rapid type of titration, frequently used in quality control applications. EPC Mode, Equivalence Point Calculation. The user only needs to know in which area the equivalence point of a reaction is to be found. The titrator will add reagent quickly until the area is reached and once there will calculate exactly the equivalence or inflection point of the titration. This is very useful in mv titrations, e.g. argentometry, where the equivalence point is always detected in the same area but where the exact potential may vary depending on electrode wear. RS Mode, Reaction Study. The instrument studies the behaviour of a sample during titration, so as to optimise later titration of this kind of sample. EPD: the flow rate decreases as the ph comes closer to the End Point. Fig. A. The EPC, equivalence point calculation, is 120 mv Fig. B. The equivalence point calculation, has moved to 160 mv Sample dosing without pipette: automatic levelling Using a TitroMatic equipped with peristaltic pumps, either integrated or using external model 86 90, the user need no longer pipette large volumes of sample. Polypropylene vessels, of identical shape and size, are used for this. The user need only pour an approximate amount of the sample in the vessels and the levelling system will draw up any excess, adjusting the volume exactly. Reproducibility over 1%. RS: Study of a reaction from a sample

3 114 TitroMatic (continued) Titromatic 1S 1S-2B 2S 2S-2B Elements Syringes Pumps their function Universal versions There are several versions, the differences among them being the elements they include. Thus: One titrant ready Two titrants ready - - Double dosing of reagent - - Dosing sample without pipette - - Dispensing auxiliary reagents - - Automatic sensors cleaning - - Two RS 232 C interfaces: One bi-directional to printer or PC. Another for connection to any CRISON automatic sample changer. Data Logger, storage of results which can be queried on screen, printed or sent to a PC at any time. Real-time clock calendar Connectable peripherals Sensors: ph and redox electrodes ion selective electrodes photoprobes temperature probe (Pt 1000) Bar-code scanner Magnetic stirrer Separate peristaltic pump module PC keyboard PC or printer Sampler or Balance The separate pump can be connected to all versions. Key features common to all TitroMatics They can store different titration programmes Self-test programme, for calibrating the burette in the user s own laboratory. Syringes: 10 ml standard. 2.5 and 5 ml optional. Versions 2S, with 2 syringes, can also be turned into a 20 ml burette, by adding 2 10-ml syringes. Two TitroMatics can be connected to the same Sampler at the same time. Precision ph-meter. ph calibration with criteria for rejecting electrodes in poor condition. Re-calibration warning once the programmed time is exceeded. Backlit, liquid crystal graphic display. Highly-functional, long-life keypad. Connection for external PC keyboard, making it easier to add text such as report headers, sample code, users, etc.

4 115 External pump module Display examples Measurement of ph and temperature. Titration reagent load on first startup The automation of certain processes sometimes requires the use of one or several peristaltic pumps. The pump can be fitted to all versions of the TitroMatic. Printer 82, optional The results obtained, programmes in memory, etc., can be printed out on a printer, see examples. Calibrating ph. Second point 4.01 One of the screens, after calibration. Calibration data, second screen During titration End of titration TiCom software for data capture from a PC TitroMatics can be connected directly to a PC. The TiCom Programme, developed by CRISON, makes it easy to use. For further information, please see page 130

5 116 TitroMatic (continued) Technical specifications common to universal and specific TitroMatic Non-volatile memory Up to 5 titration programs with the TitroMatic 1S. Up to 10 with the TitroMatic 2S. Burette auto-calibration program. Clock / calendar. Header texts: 2 lines x 40 characters. Name of up to 4 operators. Program comments: 8 lines x 40 characters. Up to 50 results stored in the Data Logger. Languages Display Keypad English, spanish, french, italian. Graphic backlit liquid crystal display, 128 x 64 dots. Measuring ranges ph , mv ± 2000, ºC Resolution Measuring error (±1 digit) Reproducibility (±1 digit) Temperature compensation ph calibration Membrane, 7 keys. Protected PET material. Guaranteed for up to 6 million strokes per key ph, 1 mv, 0.1ºC ph, 1 mv, 0.2ºC. ±0.01 ph, ±1 mv, ±0.1ºC. With ATC Pt 1000 probe or entering data using the keypad. Syringe volume Standard 10 ml. Optional: 5 and 2.5 Resolution Dispensing accuracy Reproducibility of the dispensing Materials in contact with the liquid Inputs and outputs Power supply In 1, 2 or 3 points, validity 0 h 7 days. Automatic recognition of technical buffers. ph 2.00, 4.01, 7.00, 9.21 and (at 25ºC). Special calibration, 1 selectable point between 0 14 ph. Accepted electrode values: Slope mv/ph, at 25 ºC. Sensitivity %. Asymmetry potential ± 40 mv. Rejection of defective electrodes. Expired calibration warning. 1/40000 of the syringe volume. Electrical safety Meets EC, EN (as relative error) 0.2% for volumes higher than 10 % of the syringe. ±0.1% for volumes higher than 10 % of the syringe. Syringe: glass borosilicate and PTFE. Electrovalve: PTFE and KEL-F. Tubes: PTFE. Measuring electrode, BNC connector. Reference electrode, banana Ø 4. ATC, Pt 1000 type, telephone connector or banana Ø 4. External keyboard, minidin connector. RS 232C bidirectional for PC or printer, telephone connector. RS 232C, for Sampler or balance, telephone connector. Stirrer control: On/Off and speed, RCA connector External pump control, telephone connector 24 VAC, 1.25A, 30 VA external power supply. EMC (Electromagnetic compatibility) Meets EC, EN and EN Permitted ambient conditions Enclosure Physical parameters Specifications subject to change without notice Certificates Supplied with the EC Declaration of Conformity as per directive EMC 89/336/EC, and specifications certificate. For further information, please see page 132. Operating temperature, C. Storage and transport temperature, C. 80%, relative humidity, non condensing. ABS and enamelled steel. Weight: 4 kg approx. Dimensions: 130 x 160 x 300 mm. Equipment composition Code Instrument Syringes Pumps Electrode ATC TitroMatic 1S, universal TitroMatic 1S 2B, universal TitroMatic 2S, universal TitroMatic 2S 2B, universal PLUG-IN POWER SUPPLY: The instrument is supplied with a 230 VAC plug-in power supply. For 115 VAC, please specify when ordering SENSORS: Universal TitroMatics are supplied without sensors. Select the ones most appropriate for your application, see pages 36 ACCESSORIES: TitroMatics include a stirrer, a sensor support, electrode cable and a set of buffer and electrolyte solutions. OPTIONAL ACCESSORIES: Sampler, printer, etc. See page 127