Average recovery

I which, for an average recovery of 98.1% gives a relative standard deviation of approximately 0.7%. If the acid s concentration is controlled such that its effect approaches that for factors B, C, and F, then the relative standard deviation becomes 0.18, or approximately 0.2%. 

On the other hand, quantitative extraction requires complete and exhaustive extraction and no material can be lost. To assure complete extraction when a food is analyzed for the first time in a laboratory, it is useful to carry out two or three extractions, pool the solvents, and keep separate the next extracts to verify the presence of carotenoids. Usually four to six extractions are enough to remove the carotenoids completely from a sample. The extraction can be carried out in a blender, vortex, or with a mortar and pestle. Accelerated solvent extraction (ASE), an important extraction technique in residue analysis, currently attracts interest due to its short duration, low level of solvent use, and high extraction yield. The average recoveries for all carotenoids with the exception of norbixin ranged from 88.7 to 103.3% using manual extraction and from 91.0 to 99.6% by ASE (70 bar and temperature of 40°C) both extractions were carried out with a mixture of MeOH, EtOAc, and petroleum ether (1 1 1). ... 

By definition, the determinative procedure must be able to quantify the concentration of the marker residue. For compounds with a tolerance, it is critical that the analysis be able to determine accurately if the concentration of the marker residue is above or below the tolerance in the target tissue. The CVM guidelines for determinative procedures call for an average recovery >80% with a coefficient of variation (CV) of <10% for marker residue tolerances of lOOpgkg or greater and an average recovery of >60% with a CV of <20% for marker residues with a tolerance below 100 ppb. 

The recoveries of clomeprop and its metabolite DMPA in soil after extraction with acetonitrile-water (4 1, v/v) by HPLC/UV (234 nm) are >90% The recoveries of propanil and its metabolite, 3,4-dichloroaniline, in soil are 95 and 76%, respectively, by Soxhlet extraction and LC/PAD determination. Diflufenican is added to soil in the range 0.002-0.008 mg kg to validate the method developed by Conte et al. The average recovery from the soil by this method is 92 5%. 

The recoveries of five herbicides (ethalfluralin, trifluralin, dinitramine, butralin, and pendimethalin) added to tomato in the range 0.1 to 1 mgkg were determined using GC-ITD. The average recoveries ranged from 84 to 104%, and the detection limit of these compounds was near 0.01 mg kg ... 

For the determination of five herbicides (ethalfluralin, trifluralin, dinitramine, bu-tralin, and pendimethalin) at fortitication levels between 0.1 and 1 mg soil was extracted with ethyl acetate and the extract was purified on a Florisil column. The residues were eluted with acetone and then analyzed by GC. The average recoveries varied from 75 to 111% for GC/NPD and from 88 to 98% for GC/ITD with the LOD being 0.01 mg kg for both GC/NPD and GC/ITD. The recoveries of pendimethalin at fortification levels ranging from 0.2 to 1 mg kg determined by GC/NPD were between 96 and 101% and the LOD was lower than 0.01 mg kg ... 

The recoveries of nitrofen and oxyflourfen from green bean, bell pepper, lettuce and carrot fortified with 0.25 mg kg were obtained using GC/MS. The average recoveries ranged from 106 to 127% and the LOD was 0.05 mg kg ... 

In the above-mentioned method by Hodgeson el acifluorfen was determined by GC/ECD after the extraction with a 47-mm PS-DVB disk and derivatization with diazomethane. The conditions for GC/ECD were as follows column, DB-5 fused silica (30 m X 0.32-mm i.d., 0.25-p.m film thickness) He carrier gas velocity, 25 cm s (210°C), detector makeup gas, methane-argon (5 95), 30mLmin column temperature, 50 °C (5 min), 10°Cmin to 210 °C (5 min) and to 230 °C (10 min) injection port and detector temperature, 220 and 300 °C, respectively injection method, splitless mode. The recovery of acifluorfen from purified water, dechlorinated tap water and high humic content surface water fortified at 0.5-2.0 ug was 59-150% and the LOD was 25 ngL Acifluorfen after derivatization with various chlorofor-mates was also determined by GC/MS using an SE-54 column (25 m x 0.20-mm i.d., 0.32- um Aim thickness), and the average recovery of acifluorfen fortified between 0.05 and 0.2 ugL was 78%. ... 

For plant samples, the average recovery of flumioxazin from untreated confiol samples fortified within the range 0.1-0.01 mgkg ranged from 75 to 106%. The limit of quantitation (LOQ) is 0.01 mg kg and the limit of detection (LOD) is 0.005 mg kg. ... 

With fortification levels between 0.04 and 0.2 mg kg recoveries from soil samples range from 79 to 104%. The average recovery is 90 6% (n = 19). The LOQ is 0.02mgkg ... 

With fortification levels between 0.10 and 10 average recoveries from water... 

With fortification levels between 1 and 5 pgkg average recoveries from soil samples range from 83 to 92%. The overall recovery is 88 11 % (n = 19) and the LOQ... 

HPLC determination can be carried out for most of the neonicotinoids. The average recoveries of imidacloprid in the various crops by the HPLC/PDA method were 88-94% at a fortification level of 0.25 mg and 96-99% at a fortification level of 0.05 mg kg . The overall average recovery for 30 samples was 95% with an RSD of 4.7%.12... 

According to the official Japanese HPLC/UV method, the average recovery for grapes fortified with 0.2mgkg of acetamiprid was 96% and that for tomato fortified with 0.4mgkg of imidacloprid was 90% (personal data). The recovery of nitenpyram from fruits, vegetables and rice was 66-85% at 0.2-0.8 mg kg fortification levels. The LOD was 0.0025-0.01 mg kg ... 

With fortification levels between 0.010 and 0.50mgkg, average recoveries from untreated plant matrices range from 78 to 106% with the limit of quantification (LOQ) and the corresponding limit of detection (LOD) of famoxadone being as follows ... 

With fortification levels between 0.010 and 0.10mgkg average recoveries of famoxadone from untreated soil range from 86 to 110% with an LOQ of 0.010 mg kg and the corresponding LOD being 0.003 mg kg. ... 

With fortification levels of 0.01-0.1 mg kg average recoveries of flutolanil and the metabolite M-4 from untreated potato are 80 and 76%, respectively. 

With a fortification level of 0.10mgkg the average recovery of flutolanil and the metabolites from untreated rice grain is 76%. 

The lower practical level of quantitation for fenoxycarb in air is 10 qg m using the described sampling rates and times. The average recovery obtained from fortifying and extracting the OVS tubes was 94%. 

The average recovery obtained for fenoxycarb when the analysis of pond water was performed using three-column switching LC/fiuorescence detection was 100% at fortification levels ranging from 0.001 to 10 ugL The LOQ and LOD were 0.001 ugL and 0.4 ng injected, respectively. 

The average recoveries for fenoxycarb in soil were 89, 105, and 104% for soil collected in California, Washington, and Georgia, respectively, at fortification levels ranging from 0.01 mg kg" to l.Omgkg" The LOQ and LOD were 0.01 mgkg and 0.2 ng injected, respectively. 

The average recoveries and standard deviations for the many citrus, pome fruit, tree nut, fruiting vegetables, and cotton substrate sample types were acceptable when fortified at concentration levels ranging from 0.01 to 4 mg kg. The LOQ of the method was 0.01 mgkg , except for citrus oil (0.02mgkg Q, and the LOD was 1.25 ng injected. 

Average recoveries for fenoxycarb, Ro-16-8797, and Ro-17-3192 for all animal sample substrates ranged from 80% (beef kidney) to 111% (goat kidney), 76% (goat milk) to 93% (beef omental fat), and 56% (dairy milk) to 76% (beef perirenal fat), respectively. The LOQ and LOD were 0.01 ig g and 2.5 ng injected, respectively. 

With fortification levels between 0.01 and 0.50 mg kg , average recoveries of M-1 and fenpyroximate from untreated apple and grape samples are 87 and 91% with the limits of determination being 0.01 and 0.05 mg kg respectively, for the apple and grape samples. 

Theobromine was determined by GC in various foods (bitter chocolate, milk chocolate, chocolate cake, cocoa powder, chocolate milk), and results are given in graphs and tables.27 Homogenized samples were boiled in alkaline aqueous media, then fat was extracted with n-hexane. The aqueous layer was acidified with diluted HC1 and NaCl was added. Theobromine was extracted from this treated aqueous solution with dichloromethane and the extract was evaporated to dryness. The residue was redissolved in dichloromethane containing an internal standard. GC analysis was performed on a column packed with 1% cyclohexane dimethanol succinate on Gaschrom Q, with FID. Average recoveries were 99 to 101%, coefficient of variation was less than 3% and the limit of detection for theobromine in foods was about 0.005%. 

He et al. [25] described an ultraviolet spectrophotometric method for the quantitative determination of miconazole in liniments. The drug was analyzed at 272 nm, the average recovery was 99.76% and the relative standard deviation was 0.3%. 

Guo et al. [53] developed a gas chromatographic method for the analysis of miconazole nitrate in creams and injections. The conditions were flame ionization detector, stationary phase of 5% SE 30 support of Chromosorb W (AS-DMCS, 80—100 mesh) packed column 3 m x 3 mm column temperature 275 °C injection temperature 290 °C and diisooctyl sebacate and internal standard. The average recoveries for creams and injections were 97.7 and 101.4%, respectively. The relative standard deviations were 2.2 and 1.3%, respectively. 

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