Flame photometry
Flame photometry (AES) is particularly suitable for the quantitative determination of alkali elements such as sodium (Na), potassium (K) and lithium (Li) and earth alkaline elements like calcium (Ca). The measurement by flame photometer is carried out for these elements simultaneously in one step.
Currently, elemental analysis is often carried out with complex procedures such as AAS, ICP-OES, titration or with ion-selective electrodes. Now a change is emerging and the proven measurement technology of AES flame photometry is replacing these often very expensive and time-consuming techniques.
Consistent modernization of AES(atomic emission spectroscopy) and a special focus on safety concepts open up completely new fields of application for many cost-sensitive customer groups – from automated incoming goods inspection to the qualification of FFP masks in accordance with DIN 149. With costs of just 1 cent per measurement, the FP-8000 series is the most economical measurement method for alkali and alkaline earth metals.
parts per billion
ppb is a dimensionless concentration specification and the abbreviation for "parts per billion". It is used, for example, in residue analysis and indicates how many device weights or volume units of a substance are contained in one billion units of another substance. Example: For the production of microchips, the semiconductor industry requires silicon that contains less than 1 ppb of foreign atoms as contamination - i.e. more than 99.9999999% pure silicon.
Atomic emission spectrometry
Atomic emission spectrometry (AES) is an analytical method that is primarily used to determine the concentration of alkali and alkaline earth metals in aqueous solutions. The determination is cost-effective, precise and fast. It is a relative measurement in which the unknown concentration of a sample is determined by comparison with a concentration known as a standard.
parts per million
The concentration ppm is the abbreviation for "parts per million" and means parts per million. A value of 10 ppm means, for example, that there are 10 milligrams of substance in one kilogramme of another substance. As water at room temperature has a density of approximately 1 L per kilogram, ppm is often equated with mg/L in analysis. Example: Mineral water may only be labelled as "low in sodium" if the sodium content of the water is below 20 ppm.
How does a flame photometer work?
What is measured with the flame photometer (AES)?
Everybody knows the basic principle of AES from the chemistry lab: if you bring potassium or alkaline elements into a hot flame, a flame colour characteristic of the respective element appears. In AES laboratory measurement, the analysis substance is sucked in as an aqueous solution at the push of a button and atomised using compressed air as a carrier gas (aerosol). After that, it is sprayed into a dimly lit flame. The thermal excitation of the flame causes the atoms to glow – each with its own characteristic wavelength.
Measurement of the elements Na, K, Ca and Li
The emitted radiation is selected by a suitable optical filter for each element, so that only the light of one wavelength reaches the corresponding photodetector. Several detectors are used simultaneously as standard, allowing the simultaneous determination of several elements.
The higher the concentration of an element, the more intense the emitted light is. The concentration of the measuring solution is determined via the luminance. Modern flame photometers automatically calculate the necessary curve adjustments, which compensate for non-linear effects and enable high quantitative precision.
Open and see the analysis process in detail
Measurement with the flame photometer
Atomic emission spectrometry for determining the concentration of liquids delivers a measurement result accurate to 8 digits in 30 seconds and fulfils all important industry standards. Our devices offer up to 120 measurements per hour and fully automatic measurement operation is available 24 hours a day.
Highly accurate measurements thanks to ideal sample, gas and air mixture
By adding an aqueous standby solution, the analysed substance is automatically diluted to the required concentration. Afterwards, the aqueous solution is sucked into the atomiser and atomised extremely finely with the use of the Venturi effect. Large droplets are collected in the atomiser chamber and discharged passing a droplet sensor. The monitoring of the reject serves as a control parameter with which the sample flow and atomisation can be optimally adjusted.
Stable measured values thanks to a defined flame configuration
The finely atomised sample is mixed with the fuel gas in the gas mixing chamber to create an ideal sample, gas and air mixture. Propane or acetylene can be used as fuel gas.
To achieve stable measured values, the flame must burn very evenly.12 gas outlets model a flame shape that is optimised for the AES measurement. Air flow stabilisation ensures a constant flame profile, which is additionally protected by a glass cylinder.
Precise determination of concentration based on highly sensitive photo sensors
The elements under test, such as sodium, potassium, calcium and lithium, emit light with a characteristic wavelength as a result of thermal excitation. The different wavelengths are detected by high-precision photosensors. This allows simultaneous measurement on up to 5 different elements. Alternatively, it is also possible to detect different concentration ranges of the same element.
Safety with efficient cooling and monitoring
To increase safety for the user, an integrated cooling air flow reduces the hot exhaust air to below 50 °C. In addition, our unit continuously monitors the flame. In case of irregularities, the safety valves are closed automatically. Our instruments offer sample throughput of up to 120 measurements per hour and have the option of fully automatic 24 H measurement operation. The devices delivers a measurement result accurate to 8 digits in 30 seconds and meets all important industry standards.
AES - Comparison with other measurement methods
The Krüss flame photometers measure very economically. The operating costs per measurement range in the single-digit cent zone. The reason for this is the low cost is with regard to the necessary standards and gases plus the uncomplicated and maintenance-free measuring operation. For example, with alternative AAS measurements, just changing the hollow cathode lamp used for one of an element being tested may cost several hundred euros.
Combustion gases such as propane or acetylene used in the AES, on the other hand, are inexpensive and easy to handle. A further important factor is users of the FP8000 series are able to produce the necessary calibration solutions by themselfs and and with low-cost salts. In addition, our flame photometer measurements eliminate the expensive disposal of hazardous reagents and reaction products compared to alternative methods.
| AES | AAS | ICP - OES | Electrodes | Mass spectrometers | |
|---|---|---|---|---|---|
| Measurable elements | Alkali and earth alkali metals | MANY | MANY | One element per electrode | ALL |
| accurarcy | HIGH | HIGH | HIGH | MEDIUM | VERY HIGH |
| Detection limits | ppb to ppm | ppb to ppm | ppb to ppm | ppb to ppm | ppt and below |
| Cost per measurement | LOW | MEDIUM | HIGH | LOW | VERY HIGH |
| Measuring rate | VERY FAST | MEDIUM | MEDIUM | SLOW | MEDIUM |
| Multi-element measurements | YES | CONDITIONAL | YES | NO | YES |
| Device operation | SIMPLE | ADVANCED | ADVANCED | SIMPLE | VERY ADVANCED |
| Method creation | VERY SIMPLE | SIMPLE | COMPLEX | SIMPLE | COMPLEX |
| 24/7 - Measurement mode | YES | YES | YES | CONDITIONAL | CONDITIONAL |
An article on element analysis with flame photometers (AES) was also published in the journal LABO. PDF-download LABO August- edition or you can read the online article right on the LABO website.
Areas of application
Atomic emission spectrometry is a technology that complies with all important industry standards. The technology is cutting-edge, fast, powerful and highly accurate.
Thanks to many technical improvements, the range of applications is now very broad: The flame photometers in our FP8000 series are particularly suitable for industrial processes with high demands on reliability or for unrestricted continuous operation. continuous operation and on top offers safe remote control options
The modular design of our devices means that functions can be expanded at any time with retrofit kits. This makes it possible to react immediately to changes in application requirements, e.g. with an autosampler or an automatic dilution device (diluter).
Determining the concentration of alkali and alkaline earth elements Flame photometer are essential measurement instruments in many laboratories. We have created an overview of the most important Applications and the recommended device models.
How to use
Flame photometer – all the advantages at a glance.
Complex laboratory analysis usually requires costly and time-consuming staff training and careful method development. The control of our flame photometers requires little training, as the measurement technology is uncomplicated and the FP8000 series devices in particular have automated safety mechanisms and intelligent measurement data evaluation. Our customers appreciate the simple, intuitive operation of the user-friendly software.
The FP8000 series allows the use of self-prepared Calibration standards with freely selectable concentrations.
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