Water Testing Spectrophotometer SpectroDirect
Spectrophotometer for water and waste water testing 330 - 900 nms.
Applications: Waste Water, Drinking Water, Industrial Process Water, Scientific & Research, Governmental and Private Laboratories.
TheSpectroDirect is a modern single-beam spectrophotometer with an excellent price/performance ratio that is specifically designed for water testing. The instrument is equipped with a wide range of pre-programmed methods based on the proven range of AQUALYTIC® tube tests, tablet reagents, liquid reagents and powder reagents (Vario Powder Packs).
TheSpectroDirect is a single-beam spectral photometer (see illustration). The light source is a tungsten halogen lamp with flash function. The lamp is switched on only momentarily during of the measurement process1), so there is no need for a warm-up period. TheSpectroDirect is ready to perform a self-test as soon as it is switched on. The light passes through an entry slot to the monochromator, where it is split into spectral ranges. The monochromator is a holographically produced, transparent grating. The movable mirror ensures that light of the desired wavelength is focused automatically so that it passes through the exit slot, into the sample chamber and therefore through the water sample. The light that is not absorbed by the sample travels to the silicon photodiode detector. This signal is then evaluated by a microprocessor and shown as a result in the display. 1) (Exception: permanent light is used for a wavelength scan).
Multifunctional sample chamber
Power supply for SpectroDirect
The required input voltage is 12 V. TheSpectroDirect is connected to an external power pack as standard. Battery operation is also possible by using an external energy station (see Accessories).
This spectrophotometer can be calibrated using a Secondary Standard Filter Set (order code 711160) which is N.I.S.T traceable. Furthermore the instrument may be calibrated for each method in a "user calibration mode with N.I.S.T traceable standards.
On the back of the SpectroDirect photometer, there is an RS232 interface with a 9-pin D-Sub connector for connection of a PC or a printer with serial interface (see accessories).
Every result is printed with date, time, reg. no, code no., measuring range and method number.
You can store results of programmed and userspecific methods (polynomials) in a memory with a capacity of 1000 data sets. Alongside the result, the data sets contain information on method, date and time of the test.
The user prompt is a convenient and easy to understand feature that guides the user step by step all the way through to the test result.
Zero calibration and measurements
The user chooses the desired method either from the method list in alphabetical order or by entering a numerical code. If desired additional information like the required vial, the reagent type and the measuring range can be displayed using the functional keys. The date and time are shown in the display by pressing the "clock key". TheSpectroDirect automatically selects the correct wavelength. Zero calibration is performed with the water sample by pressing the ZERO key. A characteristic coloration develops when you add the indicator to the water sample. Press the return key to initiate the measurement (which starts either immediately or after the time required for colour development).
With some methods, after adding the indicator to the water sample, the user has to wait for a predefined colour reaction time. This time interval is shown in the display. The remaining time is displayed continuously. An alarm sounds during the last 10 seconds of the time periode. Measurement then starts automatically, and the result is shown in the display. The countdown function can be switched off to allow rapid processing of a series of samples.
Differentiation of results
TheSpectroDirect allows differentiated tests for certain methods. With the Chlorine method, for example, differentiated measurement is possible for free, combined and total chlorine.
TheSpectroDirect is ideal for routine laboratory use and is equipped with additional functions for user-specific applications. One example is the creation of a user-defined method for a routine check.
A wavelength scan is performed over the user-defined interval between 330 and 900 nm. The display shows the graph of the spectrum; if the user presses a key, the display also shows a data list with the corresponding maximum and minimum absorption levels.
Using this function, the operator can, for example, carry out measurement of standards with different concentrations using the userselected wavelength in order to obtain the data pairs required for a polynomial. Result output is in Abs and % Transmission.
With the help of an external mathematical program, the corresponding polynomial is created from data pairs (concentration/absorption). A known polynomial may also be used. 10 order polynomials (y = A+Bx+Cx2 +Dx3 +EX4 + FX5) can be stored together with user-specific parameters such as wavelength, measuring range, unit and number of decimals (up to three).
This function can be used to measure 2 to 8 known standards. On the basis of the concentrations/ absorption pairs obtained, the photometer will calculate a linear interpolation between the measured points. Up to 5 methods can be stored for further sample measurements.