Residue methods for determining

Bonet-Domingo, E., Grau-Gonzalez, S., Martin-Biosca, Y., Medina-Hemandez, M.J., Sagrado, S. Harmonized internal quality aspects of a multi-residue method for determination of forty-six semivolatile compounds in water by stir-bar-sorptive extraction-thermal desorption gas chromatography-mass spectrometry. Anal. Bioanal. Chem. 387, 2537-2545 (2007)... 

Krause, R.T. (1980). Muki residue method for determining jV- methy Icarbamate insecticides in crops, using UFLC- J. Assoc. Offc- Anal Chew. 63, 1114-1124. 

Krause, R. and August, EM. (1983). Applicability of a carbamate insecticide mult [residue method for determining additional types of pesticides in fruits and vegetables, Arsoc. Off. Ami. Chem- 66. 234-240-... 

Volmer et al. studied phenylureas and sulfonylureas by TSP-LC-MS after sample concentration by Cjg SPE [175]. 15 phenylurea- and 1 thiourea pesticides besides 112 polar pesticides from other pesticide classes were examined by TSP ionisation, detection limits and TSP mass spectra of these polar compounds were presented [245], Besides other polar pesticides, the phenylurea pesticides isoproturon and diuron were on-line concentrated on a precolumn from several surface and drinking water samples and then determined by TSP-LC-MS [247]. A multi-residue TSP-LC-MS method was published by Moore et al. for the determination of the urea pesticides chlortoluron, diuron, isoproturon, and Unuron in water samples after Cig-SPE [248]. Ci8 Empore disks were applied to concentrate phenylureas from river water and spiked seawater samples prior to TSP-LC-MS. Detection limits of 2-20 (ig L and recoveries between 80 and 125% were observed [239]. TSP-LC-MS (SIM) in the positive mode allowed determination of the urea pesticides chlor-bromuron, diuron, linuron, metobromuron, monuron, neburon in apples, beans, lettuce, peppers, potatoes and tomatoes with detection limits of 0.025-1 ppm [255]. 20 other polar pesticides, linuron, which was under suspicion of being a dietary oncogenic risk (US Natl. Res. Council) was determined by TSP-LC-MS a single rapid procedure in vegetables with detection limits of 0.05-0.10 ppm [270]. TSP-LC-MS and ESI were used in a multi-residue method for determination of the sul-... 

Eluorspar assay may be completed by fluoride determination alone, because the mineralogical grouping rarely iacludes fluorine minerals other than fluorite. Calcium can be determined as oxalate or by ion-selective electrodes (67). SiUca can be determined ia the residue from solution ia perchloric acid—boric acid mixture by measuriag the loss ia weight on Aiming off with hydrofluoric acid. Another method for determining siUca ia fluorspar is the ASTM Standard Test Method E463-72. 

NEW METHOD FOR DETERMINATION OF DRY RESIDUE IN NATURAL WATER BY MEANS OF DIRECTED CRYSTALLIZATION... 

Kasprzyk-Hordern B, Dlnsdale RM, Guwy AJ (2007) Multi-residue method for the determination of basic/neutral pharmaceuticals and illicit dmgs in surface water by solid-phase extraction and ultra performance liquid chromatography-positive electrospray ionisation tandem mass spectrometry. J Chromatogr A 1161 132-145... 

Ambrus A, Visi W, Zakar F, et al. 1981. General method for determination of pesticide residues in samples of plant origin, soil, and water. III. Gas chromatographic analysis and confirmation. J Assoc Off Anal Chem 64 749-768. 

Owing to the complexity of multi-residue methods for products of animal origin, it is not possible to outline a simple scheme however, readers should refer to methods described in two references for detailed guidance (Analytical Methods for Pesticides in Foodstuffs, Dutch method collection and European Norm EN 1528. ) There is no multi-method specifically designed for body fluids and tissues. The latter matrix can be partly covered by methods for products of animal origin. However, an approach published by Frenzel et al may be helpful (method principle whole blood is hemolyzed and then deproteinized. After extraction of the supernatant, the a.i. is determined by GC/MS. The LOQ is in the range 30-200 ag depending on the a.i.). 

As a special service, the German authority has published reviews on residue analysis concerning new a.i. contained in plant protection since 1996, including selected physical-chemical data. Recoveries obtained in fortification experiments and LOQs for analytical methods for determination in crops, food of plant and animal origin. 

A method for determining the LOD and LOQ for water samples was proposed by the US EPA. This method has also been discussed by Roy-Keith Smith in his book titled Handbook of Environmental Analysis .The method has also been proposed by the US EPA in their guidelines for Assigning Values to Non-detected/Non-quantitied Pesticide Residues in Human Health Pood Exposure Assessments . ... 

T. Pihlstrom, B- Kajrap, and A. Valverde, ValidationdataforlSpesticidesincludedinthemulti-residue method for analysis of pesitddes in fruit and vegetable using ethyl acetate extraction, GPC cleanup and GC determination, in Pesticide Analytical Methods in Sweden , Part 1, Rapport 17/98, National Food Administration, Uppsala (1998). 

Crescenzi et al. developed a multi-residue method for pesticides including propanil in drinking water, river water and groundwater based on SPE and LC/MS detection. The recoveries of the pesticides by this method were >80%. Santos etal. developed an on-line SPE method followed by LC/PAD and LC/MS detection in a simultaneous method for anilides and two degradation products (4-chloro-2-methylphenol and 2,4-dichlorophenol) of acidic herbicides in estuarine water samples. To determine the major degradation product of propanil, 3,4-dichloroaniline, the positive ion mode is needed for atmospheric pressure chemical ionization mass spectrometry (APCI/MS) detection. The LOD of 3,4-dichloroaniline by APCI/MS was 0.1-0.02 ng mL for 50-mL water samples. 

The muiti-residue method for aiachior, acetochior, and metoiachior determines the concentrations of these anaiytes in groundwater and surface water. This method in-voives the addition of a deuterated intemai standard to the water sampie, concentration of the anaiytes on an SPE coiumn, eiution of anaiytes, concentration of the eiuate to a set voiume, and anaiysis by GC/MS. The use of internai standards compensates for recovery tosses, but separate experiments were conducted to ensure that recoveries were within 70-i20%. The method was vaiidated over the range of 0.05-20 xgL for aii components and is presented in Section 6. 

The current residue method for the determination of terbacil and its metabolites in agricultural commodities follows the Pesticide Analytical Manual , Volume n, ... 

One application using MAE is a method to determine imidazolinone herbicides and their respective metabolites in plant tissue." Current residue methodologies for determining imazethapyr (imidazolinone herbicide) and its metabolites in crops involve laborious, time-consuming cleanup procedures after an aqueous/organic extraction. 

The total-chlorine method for determining residues of benzene hexachloride, chlordan, and toxaphene has also been used 55) in experiments where it was known that these insecticides had been applied. With benzene hexachloride, which is known to give off-flavor to some crops, it has not been demonstrated that a relation between organic chlorine values and off-flavor exists. In fact, in most cases where off-flavor was attributed to benzene hexachloride, it has not been possible to detect organically bound chlorine. 

The availability of Compound 118 for wide scale experimentation in the field of agricultural, household, and public health uses makes necessary a method for determining minute amounts such as would be present in spray or dust residues on plants and in biological fluids and tissues. 

Jelic A, Petrovic M, Barcelo D (2009) Multi-residue method for trace level determination of pharmaceuticals in solid samples using pressurized liquid extraction followed by liquid chromatography/quadrupole-linear ion trap mass spectrometry. Talanta 80 363-371... 

Another, necessarily much less precise, method for determining n is available from the kinetic experiments [1]. At the end of these reactions, at the precise instant at which the reaction mixtures turned yellow, a very fast reaction took place (Figure 5). This represents the polymerisation of the residual styrene by a true cationic reaction caused by the ions formed from the ester at the point where the styrene concentration was reduced to a level no longer sufficient to stabilise the ester. From the very small temperature rise during this final fast reaction, the number of styrene molecules polymerised could be calculated it was always about four times the initial concentration of perchloric acid. This phenomenon was particularly evident in the reactions carried out at -19 °C in which relatively high acid concentrations were used so as to obtain reasonably fast polymerisations [1]. 

Potassium bromate is a widely used dough conditioner. However, if it is used in excessive quantities in bread products then appreciable residues (> 1 mg/kg) can remain which is of concern since it is a cancer suspect agent. Its routine analysis is laborious, time-consuming and difficult by HPLC, and Cunningham and Warner (2000) described the development of an instrumental neutron activation method for determination of bromine while HPLC was used to determine bromate in selected samples. 

Posyniak A, Stec J. 1980. The method for determination of Kelevan and Kepone residues in milk. Bull Vet Inst Pulawy 24(1-4) 76-81. 

Young S, Clower M Jr, Roach JAG. 1984. Method for determination of organohalogen pesticide residues in vegetable oil refinery by-products. J Assoc Off Anal Chem 67(1) 95-106. 

A search of federal research programs in progress indicates a few projects that would fill some of the existing data gaps. Drs. Singmaster and Acin-Diaz of the University of Puerto Rico are developing methods for determining disulfoton residue levels in food commodities and for disulfoton disposal. 

Bowman MC, Beroza M. 1969. Rapid GLC method for determining residues for fenthion, disulfoton and phorate in corn, milk, grass and feces. J Assoc Off Anal Chem 52 1231-1239. 

The determination of the estimated levels of exposure is obviously a critical component of the risk assessment process. Both pesticide residue levels and food consumption estimates must be considered. Methods for determining exposure are frequently classified as deterministic and probabilistic methods (Winter, 2003). 

Especially noteworthy are the methods for determining the sequence of glycosyl residues in a complex oligo- or poly-saccharide. Methods of this type generate a series of overlapping oligomers that are separated and identified by l.c., in conjunction with either direct or indirect mass spectrometry. Most of these methods are still in the developmental stages, and they often require expensive and not-routinely available equipment (see also. Section IV,2) (see Addendum). 

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