A validation study was performed on a multiresidue method for determination of pesticide residues in agricultural products according to the method validation guideline of the Ministry of Health, Labour and Welfare of Japan. FASRAC (Food Automatic Analytical Systems for Residual Agricultural Chemicals) automatically performs extraction of pesticide residues from agricultural products with aceton...

In this paper we present a surface formulation and curved panel integration method for computing the van der Waals interaction energy between a molecular solute and aqueous solvent. This modeling problem arises in computational drug design, where one wishes to understand the energetic tradeoff between a trial drug’s interactions with solvent and its interactions with the target. We use the dive...

Introduction There are many analytical challenges encountered with the extraction and quantification of pesticide residues in difficult sample matrices such as tuber crops, like yam (Dioscorea spp.), taro (Colocasia esculenta) and sweet potato (Ipomoea batatas L.). In our experience, a workflow solution based on extraction using the accelerated solvent extraction technique, followed by determin...

An analytical ultrasound-assisted extraction (UAE) method has been optimized and validated for the rapid extraction of stilbenes from grape canes. The influence of sample pre-treatment (oven or freeze-drying) and several extraction variables (solvent, sample-solvent ratio and extraction time between others) on the extraction process were analyzed. The new method allowed the main stilbenes in gr...

A method for ethyl carbamate (EC) determination in alcoholic beverages and soy sauce was developed by GC-MS. We adopted the diatomaceous earth solid-phase extraction (SPE) column and elution solvent of ethyl acetate/diethyl ether (5:95 v/v) for sample cleaning. The in-house validation showed the limit of quantification (LOQ) was 5.0 μg/kg. In the accuracy assay, the total average recovery for w...

Methods for the evaluation of the accuracy of crystal structures of proteins and nucleic acids are of general importance for structure-function studies as well as for biotechnological and biomedical research based upon three-dimensional structures of biomacromolecules. The structure-validation program DDQ (difference-density quality) has been developed to complement existing validation procedur...

Selecting suitable cleaning agents and determining justifiable cleaning process parameters are critical prerequisites for cleaning validation. Proper selection of these cleaning agents and parameters could simplify cleaning validation efforts immensely. Process cleaners may range from a single component, such as an organic solvent, to multicomponent formulations that use multiple cleaning mecha...

Bio-macromolecular crystals contain between 10 and 90% of solvent. This solvent is mostly disordered so it cannot be interpreted in terms of an atomic model. Owing to its simplicity and yet relatively good modeling power, flat bulk-solvent model is the most commonly used model to account for disordered solvent in modern crystallographic software packages such as CNS, CCP4 or Phenix. This model ...

In this study, we demonstrate that partial least-squares regression analysis with full cross-validation of spectral reflectance data estimates the amount of polycyclic aromatic hydrocarbons in petroleum-contaminated tropical rainforest soils. We applied the approach to 137 field-moist intact soil samples collected from three oil spill sites in Ogoniland in the Niger Delta province (5.317°N, 6.4...

Probe mapping is a common approach for identifying potential binding sites in structure-based drug design; however, it typically relies on energy minimizations of probes in the gas phase and a static protein structure. The mixed-solvent molecular dynamics (MixMD) approach was recently developed to account for full protein flexibility and solvation effects in hot-spot mapping. Our first study us...