Analysis, residue behaviour and risk assessment of combination product of iprovalicarb + copper oxychloride in representative fruiting vegetables, cucurbit and in soil using LC-MS/MS and ICP-MS.

Combination product of two herbicides, i.e. iprovalicarb and copper oxychloride, is a new formulation. There is paucity of data on the dissipation pattern and risk assessment of this combination product in crops. To understand the dissipation behaviour/kinetics of this product, a supervised field trial was undertaken on cucumber and tomato. Method validation for a QuEChERS-based method for analysis of these pesticides from cucumber and tomato matrices reveals that all the parameters were within the acceptance range in accordance with SANTE. The limit of quantitation (LOQ) for iprovalicarb in cucumber and tomato fruits, and in soil matrices when analysed on LC-MS/MS was established at 0.01 mg kg-1. Similarly, the LOQ for copper oxychloride (as copper) on ICP-MS was established at 0.5 mg kg-1 in cucumber and tomato fruits and 5.0 mg kg-1 in soil. Dissipation of iprovalicarb was slower in tomato fruits as compared to cucumber fruits. The initial accumulation of the residues of iprovalicarb was 0.073 and 0.243 mg kg-1 in cucumber and 0.214 and 0.432 mg kg-1 in tomato fruits at standard and double dose, respectively. Similarly, copper oxychloride residues were 3.51 and 6.45 mg kg-1 in cucumber and 1.26 and 2.56 mg kg-1 in tomato fruits at standard and double dose, respectively. The residues were below LOQ in cucumber fruits, tomato fruits and soil at the time of harvest. The residues of copper oxychloride persisted till harvest time in cucumber fruits and in soil. A preharvest interval (PHI) of 3 day is recommended on safer side for the combination product of iprovalicarb + copper oxychloride. Theoretical maximum daily intake (TMDI) is less than maximum permissible intake (MPI) for iprovalicarb and copper oxychloride at both the doses from 0 day and onward. The results from the present study can be of immense importance for establishing label claims, maximum residue limits (MRLs) and risk assessment by national and international regulatory agencies.

Method validation, dissipation and residue status of fluopicolide and fosetyl-aluminium in citrus using a rapid extraction method coupled with ultra-performance liquid chromatography-tandem mass spectrometry.

The dissipation and residue status of a combination of fluopicolide and fosetyl-aluminium (fosetyl-Al) in citrus were evaluated in an experimental field. An efficient and sensitive liquid chromatography-tandem mass spectrometry, with rapid extraction, was carried out according to the SANTE guidelines. During the method validation, the recovery was within the range of 106.1-117.5, 94.4-115 and 85.4-109.5%, for fluopicolide, its metabolite 2,6-dichlorobenzamide and fosetyl-Al, respectively, with a relative standard deviation (RSD) of 0.3-10.6%. As a result, accuracy and precision at the spiking concentrations of 0.01, 0.05 and 0.10 mg/kg in citrus were within the acceptable range of 70-120% with an RSD of 20%. The amount of the deposits of fluopicolide, 2,6-dichlorobenzamide and fosetyl-Al was less than the limit of quantification (LOQ) at 0.01 mg/kg at 0 day, adhering to the application in standard [1.77 + 2.66 g of active ingredient (a.i.)/L] and double (3.54 + 5.32 g a.i./L) doses. The present study proposes that the utilisation of fluopicolide and fosetyl-Al in citrus and the soil may not pose a health or environmental hazard provided that good agricultural practices are followed.

Sustained virologic response with short-course ribavirin and peginterferon treatment in 2 patients coinfected with HIV and HCV genotype 1.

The current recommendation for the duration of treatment of patients infected with chronic hepatitis C virus (HCV) genotype 1 is 48 weeks; however, the standard regimen of peginterferon plus ribavirin bears significant adverse effects, which make completion of treatment exceedingly difficult. Reported here are 2 cases of HIV-HCV-coinfected genotype-1 patients who discontinued treatment early (after 3 and 8 weeks) because of adverse effects yet had a sustained virologic response with undetectable HCV viral loads at follow-up.