Using a flame photometer

Allow time for the instrument to stabilize. Switch on the instrument, light the flame and wait at least 5 min before analysing your solutions. 

Quantify your samples using a calibration curve (p. 251). Calibration standards should cover the expected concentration range for the test solutions - your calibration curve may be non-linear (especially at concentrations above ImrnolL, i.e. 

Analyse ali solutions in duplicate, so that repeatability can be assessed. 

Check your calibration. Make repeated measurements of a standard solution of known concentration after every six or seven samples, to confirm that the instrument calibration is still valid. 

Consider the possibility of interference. Other metal atoms may 

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Chemistry Video Consortium, Praetical Laboratory Chemistry, Edueational Media Film and Video Ltd, Harrow, Essex, UK - Flame photometry, AA and TGA measurements (using a flame photometer, using an atomic absorption spectrometer and thermogravimetric analysis). 

Flame Photometry, AA and TGA Measurements (using a flame photometer, using an atomic absorption spectrometer and thermogravimetric analysis). 

The mixtures were equilibrated isothermally for 5 hours while being stirred by a stream of inert gas. The potassium content was determined by using a flame photometer, the dihydrogenphosphate was determined acldlmetrlcally using thymolphthaleln as indicator, and chloride was determined mercurimetrically. 

The potassium released from RBC was assessed in the supernatant of centrifuged RBC suspensions using a flame photometer (IL 943 IP, Instrumentation Laboratory). ... 

The detailed design and construction of instruments used in the various branches of spectrometry are very different and at first sight there may seem to be little in common between an X-ray fluorescence analyser and a flame photometer. On closer examination, however, certain common features emerge and parallels between the functions of the various parts of the different instruments are observed. The basic functions of any spectrometer are threefold (Figure 7.4) ... 

This is achieved by using an atomic absorption spectrophotometer (or less accurately with a flame photometer). Some details could be instrument specific, so refer to the manufacturer s handbook, application data sheets, and obtain technical support if you lack experience in this area. Some general guidelines will be noted here. 

Potassium at trace concentrations in aqueous samples can be measured by a flame photometer at a wavelength of 766.5 nm. Either a flame photometer or an atomic absorption spectrometer operating in flame emission mode can be used for such analysis. 

Atomic spectroscopy is a quantitative technique used for the determination of metals in samples. Atomic spectroscopy is characterized by two main techniques atomic absorption spectroscopy and atomic emission spectroscopy. Atomic absorption spectroscopy (AAS) is normally carried out with a flame (FAAS), although other devices can be used. Atomic emission spectroscopy (AES) is typified by the use of a flame photometer (p. 168) or an inductively coupled plasma. The flame photometer is normally used for elements in groups I and II of the Periodic Table only, i.e. alkali and alkali earth metals. 

Flame photometry (see also p. 168) is almost exclusively used for the determination of alkali metals because of their low excitation potential (e.g. sodium 5.14eV and potassium 4.34 eV). This simplifies the instrumentation required and allows a cooler flame (air-propane, air-butane or air-natural gas) to be used in conjunction with a simpler spectrometer (interference filter). The use of an interference filter allows a large excess of light to be viewed by the detector. Thus, the expensive photomultiplier tube is not required and a cheaper detector can be used, e.g. a photodiode or photoemissive detector. The sample is introduced using a pneumatic nebulizer as described for FAAS (p. 172). Flame photometry is therefore a simple, robust and inexpensive technique for the determination of potassium (766.5 nm) or sodium (589.0nm) in clinical or environmental samples. The technique suffers from the same type of interferences as in FAAS. The operation of a flame photometer is described in Box 26.2. 

To obtain concentration information (x) from a flame photometer reading (y), it is necessary to find the value of x that gives the observed value of y. The Goal Seek command in Tools menu performs this task very conveniently (see "Solving a Problem Using Goal Seek..." in Chapter 10). 

Pass 0.6 N HCI at a rate of 1 B /10 minutes through the resin and collect the eluate in 1 B fractions,. nal se the fractions for cations. Typical results show that sodium starts eluting after 2 B have been collected and ceases after 7 BV Potassium elution starts at 8 BV and finishes after 14 BV have been collected. I o speed up the elution of magnesium, the molarity of the hydrochloric acid is raised to I Sodium and potassium may be conveniently estimated using the flame photometer, and magnesium by KD IW (ethylenediaminetetraacctic acid). 

An atomic absorption spectrophotometer has been applied for heavy metal determination in soils. Concentrations of potassium and sodium were determined with a flame photometer. For the determination of soil fluorides, an ion-selective electrode was used. Statistical methods were applied to describe quantitatively the relationships between industrial emissions and other components of the ecosystems. 

FES, which is used for measuring a small number of elements, is of much simpler design. For example, when sodium is analysed with a flame photometer whose flame attains 2000 °C, the sodium atoms are practically the only ones emitting radiation. To measure the emitted light, a simple optical filter put between the flame and the detector, in the absence of a monochromator, isolates a rather broad spectral band including the yellow radiation emitted by the element. 

KRUPA I do not know exactly how much SO3 is in the plume, but EPA flew the plume last summer and we also have stack analysis on it. One way people measure sulfate is to modify a flame photometer, one that would normally measure S02 An electrical chopper is used in front of the flame photcaneter and the aerosol is neutralized. Subsequently, total sulfur versus SO2 is measured. The SO2 concentration is subtracted from the total sulfur to calculate SO4 levels. The only person I know that might have done significant work on this is Etou at the University of Utah. Etough has found that sulfite, up to 30 in some smelters, may exist as a stable complex with transient metals, such as lead, copper, iron [Atmos. Environ. 12 263-272 (1978)] and Jake Hales has done the same thing on the MAP 3S study over Lake Michigan in precipitation. [Atmos. Environ. 12 389-400 (1978)]. Data of Hales indicate that maybe 10-20 of the sulfur could be as a stable sulfite. 

The widely used clinical flame photometers have been described in the section above on flame spectrometers and filter photometers. Analyte concentrations and their inherent line intensities are such that samples may be diluted greatly and various difficulties avoided. The burners are small and round so that self-absorption is slight and calibration curves nearly linear. Use of lithium added at a high concentration as the internal standard helps to correct for some of the uncontrolled variables. 

Sodium chloride as a test substance has been used in several countries and the United States. The concentration in the test hood is 15 2 mg/m and the particles have an MMAD of 0.66 0.I2 m, with a geometric standard deviation of 2.15 0.I9. Calibration is done with a flame photometer using propane supplied by an external unk. The photomultiplier analyzes die flame, and the results are processed. 

The optical densities of each sample are then recorded as a series of peaks on a chart recorder. The colorimeter can be replaced by a flame photometer in the determination of sodium and potassium or a fluorimeter as for example is sometimes used in urinary oestrogen determination. 

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