Atomic emission spectroscopy preparing sample

When the problem has been defined and needed background information has been studied, it is time to consider which analytical methods will provide the data you need to solve the problem. In selecting techniques, you can refer back to the other chapters in this book. For example, if you want to measure the three heavy metals (Co, Fe, and Ni) that were suspect in the Bulging Drum Problem, you might immediately think of atomic absorption or inductively coupled plasma atomic emission spectroscopies and reread Chapter 8 of this book. How would you choose between them Which would be more accurate More precise Does your lab have both instruments Are they both in working order What if you have neither of them What sample preparation would be needed ... 

A binder—free Na-Y zeolite with Si/Al ratio of 2.29 was obtained from Strem Chemical Co., La,Na—Y and Cs,Na-Y zeolites were prepared by exchanging Na-Y zeolite with LaCls and CsCl solution at room temperature. The percentage of metal ion exchanged in a zeolite has been determinated by Inductively-Coupled-Plasma Atomic Emission Spectroscopy and the number is used as prefix for the samples, e.g., Cs exchanged level of 667. is represented as 66Cs,Na-Y sample. 

Many metal analyses are carried out using atomic spectroscopic methods such as flame or graphite furnace atomic absorption or inductively coupled plasma atomic emission spectroscopy (ICP-AES). These methods commonly require the sample to be presented as a dilute aqueous solution, usually in acid. ICP-mass spectrometry requires similar preparation. Other samples may be analyzed in solid form. For x-ray fluorescence, the solid sample may require dilution with a solid buffer material to produce less variation between samples and standards, reducing matrix effects. A solid sample is also preferred for neutron activation analyses and may be obtained from dilute aqueous samples by precipitation methods. 

In the application of atomic emission spectroscopy for quantitative analysis, samples must be prepared in liquid form of a suitable solvent unless it is already presented in that form. The exceptions are solids where samples can be analysed as received using rapid heating electro-thermal excitation sources, such as graphite furnace heating or laser ablation methods. Aqueous samples, e.g. domestic water, boiler water, natural spring, wines, beers and urines, can be analysed for toxic and non-toxic metals as received with... 

Table I summarizes the bulk composition of the exchanged samples determined after preparation. All metals, except Na, were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Na was determined by XRF analysis. Table I gives the residual Na content, the content of the introduced metal ions (on an oxygen- and water-free basis) and the atomic ratio of the introduced ions to AP -ions. Of more significance is the last column which gives the atomic...

Except for a few attempts to vaporize directly a solid sample by a rapid heating technique, the sample for atomic fluorescence is a liquid solution that can be aspirated into a flame. The same type of sample preparation therefore is required as is necessary for flame emission and atomic absorption spectroscopy. The sample must be in solution, free of solid particles, and of low viscosity. The comparison standards should have the same physical characteristics as the sample solution. If organic solvents are used for the sample solution, they also must be used for the comparison standards. 

ETV may also serve as sample introduction for inductively coupled plasma (ICP)-atomic emission spectroscopy (AES)/MS providing the possibility of in situ sample preparation by selective vaporization of different sample components, using appropriate heating programs. By the reduction/elimination of matrix components, spectral interferences can be minimized and matrix effects in the plasma decreased. 

Inductively-Coupled Argon-Plasma Atomic Emission Spectroscopy (ICAP AES) 2.0 Any matrix NIOSH (1984A). Requires extensive sanple preparation and concentration of metal with chelating resin. Advantage is simultaneous analyses for as many as 10 metals from 1 sample. 

GC with Bourier transform infrared spectroscopy (BUR) has been used for determination of chlorophenols in drinking water [95]. Before the GC-BUR analysis, the phenols were acetylated with acetic anhydride followed by off-line SPB using graphitized carbon cartridge. GC with microwave-induced plasma atomic emission spectroscopy was used in combination with two different off-line SPB procedures [96]. Derivatization with 3,5-bis(trifluoromethyl)benzyldimethylphenylammonium fluoride in combination with MS detection in negative chemical ion mode has been used for the determination of chlorophenols in industrial wastewater [94]. As seen earlier, SPB sample preparation is a commonly integrated part of the overall system setup in GC analysis. The technique is treated in more detail in the following section. 

Chemical Analysis. Plasma oxidation and other reactions often are used to prepare samples for analysis by either wet or dry methods. Plasma excitation is commonly used with atomic emission or absorption spectroscopy for quaUtative and quantitative spectrochemical analysis (86—88). 

Operating Principles — There are many similarities between ICP-AES and the combustion flame spectroscopy techniques of flame atomic emission (FAE) and flame atomic absorption (FAA). In fact, the source of the ICP-AES has been referred to by Fassel as an electric flame. The final prepared analytical sample is presented in liquid form for analysis except for unique situations. The liquid sample is drawn (or... 

These techniques fall into two categories those considered as routine (e.g. atomic absorption and emission spectroscopy, X-ray fluorescence) and a growing number of microanalytical surface techniques (e.g. laser microprobe mass analysis [LAMMA] and sensitive high-resolution ion microprobe [SHRIMP]). Each analytical technique requires specific sample preparation prior to analysis, as summarised in Table 13.1. 

In using atomic spectroscopy analysis the sample introduction is an extension to sample preparation. To understand the limitations of practical sample introduction systems it is necessary to reverse the train of thought, which tends to flow in the direction of sample solution > nebulisation > spray chamber > excitation > atomisation. An introduction procedure must be selected that will result in a rapid breakdown of species in the atomiser to give reproducible results irrespective of the sample matrix. In designing an FI A system to carry out atomic emission and to generate efficient free atom production for excitation the following criteria must be adhered to as closely as possible ... 

Argon plasma offers a number of advantages as a source for emission spectroscopy. Argon is an inert gas and will not react with the sample so chemical interference is greatly reduced. At plasma temperatures, atomization is complete and elemental spectra do not reflect molecular components. Detection limits are high for most elements. Accuracy and precision are excellent. In addition, ICP/OES requires less sample preparation and less sample amount than other techniques. 

Sodium and potassium levels are difficult to analyze by titrimetric or colorimetric techniques but are among the elements most easily determined by atomic spectroscopy (2,38) (Table 2). Their analysis is important for the control of infusion and dialysis solutions, which must be carefully monitored to maintain proper electrolyte balance. Flame emission spectroscopy is the simplest and least expensive technique for this purpose, although the precision of the measurement may be improved by employing atomic absorption spectroscopy. Both methods are approved by the U.S. (39), British (40), and European (41) Pharmacopeias and are commonly utilized. Sensitivity is of no concern, due to the high concentrations in these solutions furthermore, dilution of the sample is often necessary in order to reduce the metal concentrations to the range where linear instmmental response can be achieved. Fortunately, the analysis may be carried but without additional sample preparation because other components, such as dextrose, do not interfere. 

Electronic Absorption and Emission Spectroscopy Visible Spectroscopy Ultraviolet Spectroscopy Luminescence Spectroscopy Electron Spectroscopy Atomic Identification and Analysis Infrared and Raman Spectroscopy Infrared Spectroscopy Infrared Sample Preparation Internal Reflection Spectroscopy (IRS, ATR) Reflection Absorption (RAIR or IRRAS)... 

GC can achieve the highest resolution of the essential oils, but there are some significant limitations with regards to preparative scale separations. Typically, as the sample capacity is increased, the resolution of the chromatographic separation is reduced. On a lab scale, equipment is available that permits 24-hour automated and unattended separations, however, the recovery yield and sample resolution are still problematic [57]. Capillary column GC has become so routine for essential oil analysis that one rarely finds a lab without that capability. A multitude of detectors exist for GC thermal conductivity (TCD), flame ionization (FID), flame photometric (FPD), thermionic specific (TSD), photoionization (PID), electron capture (ECD), atomic emission (AED), mass spectrometry (MS), and infrared spectroscopy (FTIR) [58,59]. The TCD is used primarily with preparative-GC (packed column) because it is... 

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