Recovery anilides

The limit of detection (LOD) is an important criterion of the efficiency of an analytical method. It is characterized by the smallest value of the concentration of a compound in the analytical sample. The detectable amount of anilide compounds is in the range 0.01-0.5 ng by GC and 0.1 ng by HPLC. The limit of quantitation (LOQ) ranges from 0.005 to 0.01 mg kg for vegetables, fruits and crops. The recoveries from untreated plant matrices with fortification levels between 10 and 50 times the LOD and the LOQ are 70-120%. The relative standard deviation (RSD) at 10-50 times the level of the LOD and LOQ are <10 % and <20%, respectively. 

Using multi-analytical methods, most of the anilides, including naproanilide, propanil and mefenacet, show recoveries of >70% from 0.5mgkg fortified tomato. According to the official analytical method of the Ministry of Environment, Japan, the recovery of clomeprop fortified at 0.4mgkg in brown rice is >90% (personal data). 

A monitoring system has been established to determine 90 pesticides including anilides and 10 related degradation products in river water. Pesticide residues in the water sample are collected on a PS-2 cartridge (265-mg) at a flow rate of 10 mL min, eluted with 3 mL of acetone, 3 mL of n-hexane and 3 mL of ethyl acetate successively, and determined by GC/MS. Overall recoveries ranged from 72 to 118%. Recoveries of mepronil, naproanilide, propanil and flutolanil at fortification levels of 0.1 and 2 mg kg Mn water by this method were 80-112%. The LODs were 0.01 -0.1 pg L ... 

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. 

An alternative employs classical resolution using lactic acid as the source of asymmetry. Amide formation from (S)-O-acetyllactic acid and 13 gave a separable mixture of 14 [14, 15]. The lactanilides could be eliminated or reduced [16] to remove the stereogenic centre to give optically active analogues of 9 and 11. Nonetheless, a serious problem with the effective use of anilides as auxiliaries is their recovery in enantiomerically pure form. 

Ethylene dimethacrylate (5.64 g), methacrylic acid (0.52 g 6.0 mmol), L-phenylalanine anilide (0.25 g 1.5 mmol), and of AIBN (W mg) in acetonitrile 98.2 mL) were mixed in a glass tube. After degassing, the tube was sealed under nitrogen and consecutively heated for 24 h each at 60, 90, and 120 °C. Subsequently, the polymer was ground and subjected to continuous extraction in acetonitrile for 24 h. To determine the recovery of imprint molecules, the extracted anilide was quantitatively determined and the polymer was investigated by nitrogen elemental analysis before and after extraction of the imprint molecule. According to these methods about 90% of the imprint molecules had been removed from the polymers. 

An APCI-LC-MS method was developed and described for the quantitative determination of the anilide pesticides alachlor and metazachlor in ground water samples. After optimization of instrumental conditions detection limits of 0.001-0.005 pg L (50-300 pg injected) could be obtained. Recovery, precision and linearity data were reported [350]. The pesticide bentazone was one of the most frequently found compounds determined by APCI-LC-MS in shallow groundwater samples from twosandy and two clay catchment areas [351]. 

A study with environmental samples was performed analyzing 26 non-acidic (e.g. organophosphorus, carbamate, triazine, anilide, N-substituted amine and phenylurea type) and 13 acidic (urea and phenoxy acid type) target pesticides simultaneously by ESI-LC-MS with recoveries of about 80% [500]. Drinking, ground and... 

In a study covering a wide range of polar and acidic pesticides deethylatrazine and atrazine besides anilide, phenoxy acid, phenylurea, carbamates and other types of specific pesticides in river water were determined by ESI-LC-MS and MS/MS. Recoveries, depending on preconcentration steps, obtained with different SPE materials (PLRS-S, Hyshere-1, LiChrolut EN and Isolute ENV -i-) and at different pH values were reported [502]. Sixteen of the most widely used pesticides in Southern Italy were monitored in surface water samples taken in the Calabria region. Triazines were determined quantitatively by LC-UV and ESI-LC-MS(-i-) and were confirmed by MS [537]. In another study the simultaneous determination of 26 non-acidic (base and neutral e.g. triazine, carbamate, anilide, N-substituted amine, urea and organophosphorus type) and 13 acidic (sulfuron and phenoxy acid type) pesticides in natural waters was performed using ESI-LC-MS. Recoveries... 

---