Fungicides detection limits

A method has been developed for the analysis of the fungicide TBZ in fruits, potatoes, and their processed products. Extraction was performed with a basic solution (ethanol with 2 M ammonium chloride, pH 9.5, with 14.5 M ammonium hydroxide) and methylene chloride. Tribendazole was partitioned into methylene chloride with a polytron. No further cleanup was needed. Total analysis time, including extraction, was 25 min per sample. Recoveries ranged from 77 to 135%. Detection limits were 1.0 ppb for juice, fruits, and potatoes and 2 ppb for bulk concentrates (12). 

Caverly and Unwin [536] have described a rapid and sensitive technique for the determination of the residues of the fungicides furalaxyl and metalaxyl in soils. The soil sample is extracted with acetone in a Soxhlet apparatus and then the extract is analysed by gas chromatography using NP-selective detection. Recoveries are generally in excess of 80% with detection limits of 0.1 mg/kg. 

Fungicide type Sample type Sample preparation Analytical finish Detection limit Reference... 

A high performance liquid chromatographic procedure has been described [3] for the simultaneous determination of the fungicides sodium-A-methyldithiocarbamatc and methylisothiocyanate in surface waters and in sewage, based on their separation on a reversed phase column with a miscellar mobile phase (hexadecyltrimethylammonium bromide) in 1 1 v/v methanohwater buffered to pH6.8. Detection Limits were 70 and lpg dm 1 when the analysis was performed with an ultraviolet detector at 247nm. 

Many detectors have been used to detect pesticides and herbicides in SFC. Among these detectors, the flame ionization detector (FID) is most commonly used for detection of a wide range of pesticides and herbicides, with a detection limit ranging from 1 ppm (for carbonfuran) to 80 ppm (for Karmex, Harmony, Glean, and Oust herbicides). The UV detector has frequently been used for the detection of compounds with chromophores. The detection limit was as low as 10 ppt when solid-phase extraction (SPE) was on-line coupled to SFC. The mass spectrometric detector (MSD) has also been used in many applications as a universal detector. The MSD detection limit reached 10 ppb with on-line SFE (supercritical fluid extraction)-SFC. Selective detection of chlorinated pesticides and herbicides has been achieved by an electron-capture detector (ECD). The limit of detection for triazole fungicide metabolite was reported to be 35 ppb. Other detectors used for detection of pesticides and herbicides include thermoionic, infrared, photometric, and atomic emission detectors. 

Culvularia lunata spores were grown on TLC plates, where inhibition zones developed. Semi-quantitative determination of the fungicides was carried out by comparing the areas with known standards. The detection limit of this method was about 10-30 ng (110)... 

Although hexachlorobenzene (HCB) was used as an active component of insecticides and fungicides in the UK until the 1970s, its major source to the environment now is now as a by-product of industrial processes such as aluminium smelting and production of perchloroethylene and vinyl chloride monomer.65 The MAFF survey mentioned earlier did not include HCB, but a later survey on milk samples from farms around potential point sources did analyse for HCB. No HCB was detected at or above the reporting limit of 1 fig/ kg in whole milk in samples from either around potential point sources or control farms.66... 

Sensitivity The limit of detection for a certain compound is determined by its affinity constant or binding constant to the interaction partner immobilized to the surface. Therefore, the choice of the capture compound affects remarkably the assay performance. Because of the opportunity to create antibodies against different kind of compounds, e.g., peptides, proteins, enzymes, vitamins, environmental pollutants, herbicides, fungicides, etc., they are frequently used as a versatile tool for sensor assay developments. 

For a range of chemically xmrelated fungicides such as ethirimol, cymoxanil, quinoxyfen and aromatic hydrocarbons (e.g.chloroneb, quintozene), resistant isolates have been detected occasionaly in limited areas. For these fungicides, the mode of action and... 

Of the more-or-less pure organic constituents detectable in water as analytical methods improve, the insecticides, fungicides, and weedkillers probably have received the most attention. Although inland surface waters have been monitored for about a decade, essentially nothing is known about pesticide levels in the ocean, and existing information comes from indicator organisms. Even current quantitative data from water analyses stretch the limits of accuracy and confirmation of identity (23). 

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