Contaminant detection

Surface defects (Section VII-4C) are also influenced by the history of the sample. Such imperfections may to some extent be reversibly affected by processes such as adsorption so that it is not safe to regard even a refractory solid as having fixed surface actions. Finally, solid surfaces are very easily contaminated detection of contamination is aided by ultra-high-vacuum techniques and associated cleaning protocols [24]. 

Biosensors ai e widely used to the detection of hazardous contaminants in foodstuffs, soil and fresh waters. Due to high sensitivity, simple design, low cost and real-time measurement mode biosensors ai e considered as an alternative to conventional analytical techniques, e.g. GC or HPLC. Although the sensitivity and selectivity of contaminant detection is mainly determined by a biological component, i.e. enzyme or antibodies, the biosensor performance can be efficiently controlled by the optimization of its assembly and working conditions. In this report, the prospects to the improvement of pesticide detection with cholinesterase sensors based on modified screen-printed electrodes are summarized. The following opportunities for the controlled improvement of analytical characteristics of anticholinesterase pesticides ai e discussed ... 

Blank-corrected Data that have had trace contamination amounts (detected in a nonexposed sample) deducted from the total amount of contaminant detected in the sampling media. 

Renberg I., Persson M.W., Emteryd O. Pre-industrial atmospheric lead contamination detected in Swedish lake sediments. Science 1994 368 323-326. 

Partial list of contaminants detected in technical-grade and purified pentachlorophenol... 

Passino, D.R.M. and S.B. Smith. 1987. Acute bioassays and hazard evaluation of representative contaminants detected in Great Lakes fish. Environ. Toxicol. Chem. 6 901-907. 

Table 23.2 Partial List of Contaminants Detected in Technical-Grade and Purified Pentachlorophenol (All values are in mg contaminant/kg product [ppm].)... 

Feature 7. Create employee protocols for detection of contamination consistent with the recognized limitations in current contaminant detection, monitoring, and surveillance technology. 

Practical Strategies for Protein Contaminant Detection by High-Performance Ion-Exchange Chromatography... 

Major chemical contaminants implicated in food safety include pesticides, herbicides, myeotoxins and antibiotics. These analytes have been targeted by numerous groups developing SPR biosensors. As these analytes are rather small (typical molecular weight < 1,000), inhibition assay has been a preferred detection format. Examples of chemical contaminants detected by SPR biosensors include pesticides atrazine and simazine (detection limits 0.05 ng/ml and 0.1 ng/ml respectively), mycotoxin Fumonisin B1 (detection limit 50 ng/ml ), and antibiotics Sulphamethazine, Sulphadiazine (detection limits 1 ng/ml and 20 ng/ml respectively). 

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