Trace level analysis

Spark Source Mass Spectrometry (SSMS) is a method of trace level analysis—less than 1 part per million atomic (ppma)—in which a solid material, in the form of two conducting electrodes, is vaporized and ionized by a high-voltage radio frequency spark in vacuum. The ions produced from the sample electrodes are accelerated into a mass spectrometer, separated according to their mass-to-charge ratio, and collected for qualitative identification and quantitative analysis. 

H. G. J. Mol, H.-G. M. Janssen, C. A. Cramers, J. J. Vreuls and U. A. Th Brinkman, Trace level analysis of micropollutants in aqueous samples using gas cliiomatography with on-line sample enrichment and laige volume injection , J. Chromatogr. 703 277-307(1995). 

The acceptance criterion for recovery data is 98-102% or 95-105% for drug preparations. In biological samples, the recovery should be 10%, and the range of the investigated concentrations is 20% of the target concentrations. For trace level analysis, the acceptance criteria are 70-120% (for below 1 ppm), 80-120% (for above 100 ppb), and 60-100% (for below 100 ppb) [2]. For impurities, the acceptance criteria are 20% (for impurity levels <0.5%) and 10% (for impurity levels >0.5%) [30], The AOAC (cited in Ref. [11]) described the recovery acceptance criteria at different concentrations, as detailed in Table 2. A statistically valid test, such as a /-test, the Doerffel-test, or the Wilcoxon-test, can be used to prove whether there is no significant difference between the result of accuracy study with the true value [29],... 

E. Bakker and E. Pretsch, Potentiometric sensors for trace-level analysis. TrAC, Trends Anal. Chem. 24, 199-207 (2005). 

FurtmannK. 1994. Phthalates in surface water—a method for routine trace level analysis. Fresenius Journal of Analytical Chemistry 348(4) 291-296. 

Ritsema R, Cofino WP, Frintop PCM, et al. 1989. Trace-level analysis of phthalate esters in surface water and suspended particulate matter by means of capillary gas chromatography with electron-capture and mass-selective detection. Chemosphere 18 2161-2175. 

T. Reemstsma, Liquid chromatography-mass spectrometry and strategies for trace-level analysis of polar organic pollutants. J. Chromatogr.A, 1000 (2003) 477-501. 

Reemtsma, T. Liquid Chromatography-Mass Spectrometry and Strategies for Trace-Level Analysis of Polar Organic Pollutants. J. Chromatogr. A 2003, 1000, 477-501. 

Leis HJ, Fauler G, Rechberger GN, Windischhofer W. 2004. Electron-capture mass spectrometry a powerful tool in biomedical trace level analysis. Curr Med Chem 11 1585. 

One of the major problems associated with trace level analysis of perfluori-nated acids is background contamination in the analytical blanks. Because of the contamination in blanks, the limits of detection (LOD) of perfluoro-chemicals in water samples are high, in the range of several tens to hundreds of ng/L to a few pg/L (11-15). 

In food analysis, sensitivity is not the only requirement for analytical method development. Besides confirmation of the identity of pesticides, the identification of nontarget analytes is also important. One powerful tool is LC/MS, especially when it is combined with appropiate sample-treatment procedures it allows one to obtain detection limits adequate for trace-level analysis. Liquid chromatography-MS has demonstrated that it is an effective way to obtain both qualitative and quantitative information. 

The method s performance characteristics should be based on the intended use of the method. For example, if the method will be used for qualitative trace-level analysis, there is no need to test and validate the method s linearity over the full dynamic range of the equipment. Initial parameters should be chosen according to the analyst s best judgment. Finally, parameters should be agreed upon between the lab generating the data and the client using the data. 

Ion-selective electrodes in trace level analysis of heavy metals Potentiometry for the XXI century... 

Pb2+-selective electrode with LOD in picomolar range—improvements of many orders of magnitude compared to the ones known at the time [10]. Since then, many ISEs with significantly improved LODs have been reported [11-13] and the theory of the response of ISEs has been redefined 114—161. In 2001, Ceresa et al. reported the application of ISEs for trace level analysis and demonstrated the use of a Pb2+-selective electrode for the analysis of Zurich drinking water [17]. Subsequently, this work has been followed by other examples of application of ISEs for the analysis of environmental samples [18,19]. 

Analytical techniques for trace level analysis can be divided in the three principal classes ... 

Trace level analysis using ISEs was considered impossible only a decade ago. With detection limits in micromolar levels and the discrimination of interfering ions by a factor of 103-104, researchers at the time did not see any possibility of serious advances in the area and the application of ISEs in new field such as trace metal analysis in environmental samples was regarded as impossible. The potential response of an ISE in the presence of interfering ions is described by the well-known... 

Trace level analysis 45 Training of the ANN e319 Trandolapril 62 Transducer materials 479 for mercury sensors 238 Transient response 746 Transparent substrates (SOI) 100 Triclosan 520... 

An oven temperature in the range of 200°C and detector and injector temperatures around 300°C and 250°C, respectively, should give good separation, sharpness of peaks, and fast analysis time. Electron capture detector (ECD) is the most commonly used detector for trace level analysis of PCBs by gas chromatography (GC), exhibiting a response to an amount below 0.1 ng PCBs. Thus, on a capillary column, an IDL in the range of 5 pg/L can be achieved. With proper sample concentration steps, a detection level several-fold lower to IDL may be obtained. Other halogen-specific detectors such as Hall electrolytic conductivity detector can also be used to analyze PCBs. 

Coquart, V. and M.C. Hennion (1991). Interference removal in the organic trace-level analysis of aqueous environmental samples by online liquid chromatographic preconcentration techniques with two precolumns. J. Chromatogr., 553 329-343. 

Mendes, M.A. and M.N. Eberlin. 2000. Trace level analysis of VOCs and semi-VOCs in aqueous solution using a direct insertion membrane probe and trap and release membrane introduction mass spectrometry. Analyst 125 21-24. 

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