A quantitative structure–mobility relationship of organic acids using solvation parameters

Recent Progresses in Sensitive Determination of Drugs of Abuse by Capillary Electrophoresis

Background:

Today, “drugs of abuse” pose serious social problems such as many crimes, medical treatment costs, and economic repercussions. Several worldwide clinical laboratories use analytical separation methods to analyze their patient samples for drugs and poisons. In this way, they provide qualitative and quantitative data on the substances in various biological matrices (e.g., urine, plasma or serum, saliva, and breath).

Methods:

An extensive review of the published articles indicates that the use of Capillary Electrophoresis (CE) coupled with sensitivity enhancing methods is a very attractive area of interest in the assay of drugs of abuse.

Results:

This review was prepared to have a comprehensive study on applications of sensitivity enhancing methods on the determination of drugs of abuse especially from 2007 to present. The sample preconcentration approaches almost address all methods from online preconcentration (both electrophoretic and chromatographic-based methods) to offline preconcentration. Furthermore, detection system modification and capillary column fabrications were investigated in order to increase the detection sensitivity of complex samples in CE.

Conclusion:

The present review summarizes the most recent developments in the detection of drugs of abuse using CE. Although CE still has a limitation in sensitive detection, several publications in recent years have proposed valuable methods to overcome this problem.

High-Performance Liquid Chromatography Determination of Acrylamide after Its Extraction from Potato Chips

Background: Acrylamide is a known carcinogenic product that has been found among the substances such as potato chips which to be processed under the heat-treatment. In order to extract amounts of acrylamide from fried chips in market, an ultrasound-assisted liquid– liquid extraction (UA-LLE) technique is proposed. The UA-LLE coupled LLE and ultrasonication in a single step. Methods: Chips samples were dissolved in an extracting organic solvent using ultrasonication to prompt transferring of acrylamide into the organic phase. As a result, the extraction time and process efficiency were significantly enhanced through increasing the collision power and mass transfer between grounded chips and organic phase. Results: Important parameters affecting the extraction efficiency such as kind of organic solvent and its volume, re-dissolving solvent and pH were optimized. This newly proposed method has been applied to determine the trace acrylamide in potato chips samples purchased from local market. Conclusion: UA-LLE is a handy, economic and time-saving method, with high extraction yield (over 103% average recovery) and good precision (lower than 15% relative standard deviation, RSD). Most importantly, it seems this method to be an ideal pre-treatment method for the extraction of acrylamide in food matrix in food quality control laboratories.

A novel mixed hemimicelles dispersive micro-solid phase extraction using ionic liquid functionalized magnetic graphene oxide/polypyrrole for extraction and pre-concentration of methotrexate from urine samples followed by the spectrophotometric method

Methotrexate (MTX) is an anticancer drug that is widely used in a variety of cancers including primary central nervous system lymphoma. It is also administrated in the treatment of some autoimmune diseases. A simple, accurate, sensitive, and precise mixed hemimicelles dispersive micro-solid phase extraction was proposed for MTX quantification in human urine samples. MTX was quantified by spectrophotometer after dispersive micro-solid phase extraction using ionic liquid functionalized magnetic graphene oxide/polypyrrole. Interactions of adsorbent and MTX were modeled by molecular docking and the interaction energy was predicted to be -8.35 kcal/mol. A larger absolute value of binding energy represents larger adsorption strength, indicating that graphene oxide nanosheets could perform higher adsorption strength toward MTX. The concentrations of MTX were proportional to analytical response in amounts ranging from 10 to 1000 ng/mL with a good correlation (R² = 0.99). Inter- and intra-day precisions and accuracies were within the acceptable limit according to FDA guideline (15% for biological determination). The recoveries were ranging from 89 to 93% and the method was specific for routine analysis of MTX. This protocol was applied to the urine of two patients under MTX therapy received an intravenous administration of 1 mg/kg/dose of MTX with acute lymphoblastic leukemia. The accuracy of the method was confirmed by HPLC measurements.