GENERAL ANALYTICAL METHODSS

Fisk JF. 1986. Semi-volatile organic analytical methods - general description and quality control considerations. In Perket CL, ed. Quality control in remedial site investigation Hazardous and industrial solid waste testing, ASTM Spec Tech Publ 925. Vol. 5, American Society for Testing and Materials, 143-156. 

Whenever a measured value exceeds a certain threshold (an internally defined limit or a legal restriction criterion) then a confirmation procedure is recommended or even necessary. The purpose of confirmation analysis is to prove or disapprove the measurement result obtained by the usual analytical method. Generally, the difference from the confirmation procedure compared to the usual test method should be due to only either the use of a completely different separation column (with completely different retention behaviour) in the same detection system or the use of an alternative detection method with sufficient sensivity. For the latter case and especially for GC methods, the prefered procedure should be to apply analyte selective mass spectroscopy (MS) detection. In some cases, derivatisation of the analyte followed by MS detection can also be the method of choice. In the case of HPLC methods, different polarity of another column in connection with full exploitation of modern UV diode array detection systems may be useful to selectively allow confirmation of the analyte. It is extremely important to make sure that the confirmation procedure works at the restriction criterion level or other self-defined concentration limit ... 

In order to estimate these indicators, it is necessary to use various analytical methods, generally approved by USEPA or standardized by others national or international organizations such as APHA (American Public Health Association) ASTM, AOAC-Intemational or ISO. In addition to reference methods, alternative procedures or new methods can be tested and approved, according to EPA guidelines or APHA, ASTM, AOAC-intemational, and ISO protocols (AOAC, 1999 APHA, 1998 ASTM, 1999 ISO, 2001). In order to approve and validate new test procedures, confirm laboratory performance and update approved methods (Table 1.2.4) USEPA publishes both approved test methods and procedures and those that have not been promulgated. 

The analytic methods generally fall into two groups (1) those that do not require the destruction of organic materials in the sample and (2) those that require the elimination of interfering matter before the selenium content can be measured. X-ray fluorescence and some of the neutron activation analysis techniques do not require sample destruction, whereas spectrophotometry, GC, atomic absorption spectrometry, polarography, titration, spark source, MS, fluorometry, and other neutron activation analysis techniques require some degree of sample destruction. Fluorometry, atomic absorption spectrometry, and neutron activation analysis are the most frequently used methods. 

There are two sources of information from the CAC that provide guidance on the validation of analytical methods. General guidance on method validation, including single-laboratory method validation, may be found in the CAC Procedural Manual.This is supplemented by Codex Alimentarius Commission guidelines, a number of which have been adopted from harmonized guidelines previously developed by independent international scientific... 

The specific interaction antigens (analytes) and antibodies (reagents) used for analytical methods generally known as immunoassays are reflected quantitatively by changes in the activity or signal yielded by an appropriate label. The inception of HA in the immunological field results in faster and more reproducible assays. Examples are given in Table 7. 

Fluorimetric analytical methods generally have detection limits from one to four orders of magnitude... 

Although many quantitative applications of acid-base titrimetry have been replaced by other analytical methods, there are several important applications that continue to be listed as standard methods. In this section we review the general application of acid-base titrimetry to the analysis of inorganic and organic compounds, with an emphasis on selected applications in environmental and clinical analysis. First, however, we discuss the selection and standardization of acidic and basic titrants. 

Noncatalytic Reactions Chemical kinetic methods are not as common for the quantitative analysis of analytes in noncatalytic reactions. Because they lack the enhancement of reaction rate obtained when using a catalyst, noncatalytic methods generally are not used for the determination of analytes at low concentrations. Noncatalytic methods for analyzing inorganic analytes are usually based on a com-plexation reaction. One example was outlined in Example 13.4, in which the concentration of aluminum in serum was determined by the initial rate of formation of its complex with 2-hydroxy-1-naphthaldehyde p-methoxybenzoyl-hydrazone. ° The greatest number of noncatalytic methods, however, are for the quantitative analysis of organic analytes. For example, the insecticide methyl parathion has been determined by measuring its rate of hydrolysis in alkaline solutions. 

In the United States the analytical methods approved by most states are ones developed under the auspices of the Association of Official Analytical Chemists (AOAC) (3). Penalties for analytical deviation from guaranteed analyses vary, even from state to state within the United States (4). The legally accepted analytical procedures, in general, detect the solubiUty of nitrogen and potassium in water and the solubiUty of phosphoms in a specified citrate solution. Some very slowly soluble nutrient sources, particularly of nitrogen, are included in some specialty fertilizers such as turf fertilizers. The slow solubihty extends the period of effectiveness and reduces leaching losses. In these cases, the proportion and nature of the specialty source must be detailed on the labeling. 

The most important general test methods are issued as ASTM Test Methods and are periodically updated by the Polyurethane Raw Materials Analysis Committee (PURMAC) of the Society for the Plastics Industry (SPI). PURMAC has collected all pertinent analytical methods in a manual (271). 

In a general way, the identification of asbestos fibers can be performed through morphological examination, together with specific analytical methods to obtain the mineral composition and/or stmcture. Morphological characterization in itself usually does not constitute a reHable identification criteria (1). Hence, microscopic examination methods and other analytical approaches are usually combined. 

The other analytical methods necessary to control the typical specification given in Table 5 are, for the most part, common quality-control procedures. When a chemical analysis for purity is desired, acetylation or phthalation procedures are commonly employed. In these cases, the alcohol reacts with a measured volume of either acetic or phthalic anhydride in pyridine solution. The loss in titratable acidity in the anhydride solution is a direct measure of the hydroxyl groups reacting in the sample. These procedures are generally free from interference by other functional groups, but both are affected adversely by the presence of excessive water, as this depletes the anhydride reagent strength to a level below that necessary to ensure complete reaction with the alcohol. Both procedures can be adapted to a semimicro- or even microscale deterrnination. 

All main aspects of analytical and bioanalytical sciences is covered by the conference program. AC CA-05 consists of 12 invited lectures and seven symposia General Aspects of Analytical Chemistry, Analytical Methods, Objects of the Analysis,. Sensors and Tests, Separation and Pre-concentration, Pharmaceutical and Biomedical Analysis, History and Methodology of Analytical Chemistry. Conference program includes two special symposia Memorial one, dedicated to Anatoly Babko and Analytical Russian-Germany-Ukrainian symposium (ARGUS-9). 

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