Review of Characteristics and Analytical Methods for Determination of Thiabendazole

Thiabendazole (TBZ) is a fungicide and anthelmintic drug commonly found in food products. Due to its toxicity and potential carcinogenicity, its determination in various samples is important for public health. Different analytical methods can be used to determine the presence and concentration of TBZ in samples. Liquid chromatography (LC) and its subtypes, high-performance liquid chromatography (HPLC) and ultra-high-performance liquid chromatography (UHPLC), are the most commonly used methods for TBZ determination representing 19%, 18%, and 18% of the described methods, respectively. Surface-enhanced Raman spectroscopy (SERS) and fluorimetry are two more methods widely used for TBZ determination, representing 13% and 12% of the described methods, respectively. In this review, a number of methods for TBZ determination are described, but due to their limitations, there is a high potential for the further improvement and development of each method in order to obtain a simple, precise, and accurate method that can be used for routine analysis.

Development and application of an analysis method for the determination of rare earth elements in silicate-rich samples by Na2O2 sintering and ICP-MS analysis

The performance of a fast and simple analytical procedure for rare earth elements (REEs) quantification from secondary sources was investigated in the present work. Seven silicate-rich certified reference materials (CRMs) in the form of Andesite (JA-1), Basalt (JB-3), Rhyolite (JR-1, JR-2), Granite (JG-2), Granodiorite (JG-3), and Till (TILL-1), were used for the optimization and characterization of the analysis method. The optimized method was used in the analysis of nine mining wastes selected within the ENVIREE project, under the ERA-MIN Program of the 7th Framework, having as the main aim to ensure a policy securing long-term access of REEs secondary sources at reasonable costs. For silicate-rich samples efficient solid dissolution involves sintering with Na₂O₂ at 460 °C and a sample to oxidizing reagent ratio of 1:6.5. Inductively coupled plasma-mass spectrometry (ICP-MS) was used in the quantification of the REEs with aerosol dilution of samples applied to minimize the salt effect on the plasma and interface regions. The work performed in the present study clearly shows that accurate reports on the REE concentrations from geological matrices also involves as mandatory the estimation of the overall uncertainty from various sources (sample preparation or analyte measurements). In the analysis of geological samples, the proposed analysis method has on average 23% of the overall uncertainty explained by the sample preparation and 77% accounted by the analysis steps. Moreover, the method described by effective, cheap, robust and safe attributes, can be recommended as an accessible alternative to the HF wet digestion method. Although from all the investigated tailings samples, only those from Sweden and Czech Republic can be regarded as potential secondary sources for REEs, investigation of other resources with interest at European level might bring a great benefit in the general attempt to develop an economically viable method for the production of rare earth elements.

Salting-out homogeneous liquid-liquid microextraction for the determination of azole drugs in human urine: Validation using total error concept

A salting-out homogeneous liquid-liquid microextraction was proposed for the quantification of four azole drugs in human urine prior to high-performance liquid chromatography analysis. The procedure involved the mixing of the sample with acetonitrile in appropriate volumes followed by the addition of sodium sulfate solution in order to facilitate phase separation. The parameters influencing the extraction performance were studied and optimized using a two-step experimental design. The analytical procedure was thoroughly validated using the accuracy profiles as a graphical decision-making tool. The β-expectation tolerance intervals did not exceed the acceptance criteria of ±15% meaning that 95% of future results will be included in the defined bias limits. The limits of detection of the procedure were satisfactory, ranging between 0.01 and 0.03 μg/mL. The mean analytical bias in the spiking levels was satisfactory and ranged between -10.3 and 4.2% while the relative standard deviation was lower than 5.6%. Monte-Carlo simulations followed by capability analysis were employed to investigate the ruggedness of the sample preparation protocol. The developed method offers advantages compared to previously reported approaches for the same type of analysis including extraction efficiency and scaling down of the sample volume and extraction time.

Simultaneous determination of amantadine, rimantadine, and memantine in processed products, chicken tissues, and eggs by liquid chromatography with tandem mass spectrometry

A simultaneous determination of amantadine, rimantadine, and memantine in processed products (deep-fried chicken, fried chicken, fried quail egg, and grilled chicken) with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. This new method was also applicable for chicken tissue (muscle, liver, and gizzard) and eggs. The chromatographic separation was performed on a Kinetex^® XB-C18 core-shell technology column using a mobile phase of acetonitrile and 0.1% formic acid in a 10mmol/L ammonium formate solution, resulting in the complete separation of isomers (rimantadine and memantine) and any other obstructive peaks from the sample matrices. Sample preparation was performed by a modified QuEChERS method using acetonitrile and a 0.1% acetic acid extraction solution and cleaned using an Oasis^® MCX cartridge. The sample matrix had no effect on the identification of the compounds. For quantification, an external solvent calibration curve was used. This new method exhibited good accuracy ranging from 79.9% to 91.5%. The relative standard deviation of repeatability (RSD_r) ranged from 1.2% to 3.6% and the relative standard deviation of within-laboratory reproducibility (RSD_WR) ranged from 1.3% to 6.0%. These standard deviations satisfied the criteria for Japanese validation guidelines. The limit of quantification (LOQ) was 1.0μg/kg for all samples. Analyte residues were not detected in 55 samples using the validated method.