Journal of Chemical Metrology

Abstract: In the current project, the National Institute of Standards (NIS), Egypt, initiated a preliminary investigation to create a certified reference material for certain elements, including Fe, Mg, Mn, Al, Cu, and Zn, in human hair. This reference material would be a quality control sample for trace element determination. This paper studied homogeneity and short-term stability as key parameters for producing certified reference materials. ICP-OES and AAS were used to measure human hair powder samples, and the data was statistically evaluated for normality and outliers, which resulted in the measurement results being normal after removing the outliers. Also, sample homogeneity was evaluated and assessed using analysis of variance  (ANOVA), which revealed that the human hair samples produced were homogenous and stable during transportation. This CRM mainly intends to develop methods and check instrumental performance, analytical trueness, and accuracy-related to trace element analysis in human hair and similar matrices.

Today, high amounts of boron waste are generated due to the widespread use of boron and boron compounds. Boron waste in boron-producing enterprises in Türkiye reaches six hundred thousand tons annually. The utilization of boron wastes includes various stages, such as storage of refuse in appropriate places, recovery of boron from boron wastes, and utilization in proper sectors. In this study, the amounts of lead (Pb) and beryllium (Be) in three different boron samples (boron waste, boron ore, and processed boron ore) obtained from Kütahya-Emet region were determined by ICP-OES spectroscopic technique by cloud point extraction (CPE) method using 4-sulfamoylphenyl dithiocarbamate salt complexing agent. Colemanite was used as a boron ore in the study. According to the results, the optimum conditions for the recovery of lead and beryllium ions from aqueous media were found as pH=9, 0.12% (w/w) ligand, and 0.1% (w/w) surfactant concentration, 45 oC incubation temperature and 60 min incubation time. The RSD % of the method under the optimum conditions found were 2 and 2.5 for Pb2+ and Be2+, respectively. The procedure was successfully applied to boron waste samples, and Pb2+ and Be2+ recoveries between 96-105% were obtained.

In this study, Lead (Pb), Copper (Cu), and Tin (Sn) elements determined in corn samples were analyzed from three different regions of Sakarya province. A cloud point extraction (CPE) method was used for the metal determination study and analysis by inductively coupled plasma-optical emission spectroscopy (ICP-OES). In this study, optimization processes were performed in cloud point extraction 2-(4-sulphonylamidebenzo)hydrazide-1-dithiocarbamate salt as ligand and Triton X-114 as surfactant. Three different corn samples, soil samples, and certified reference materials (GBW10011 and GBW10012) were analyzed. Recovery values in corn samples were 95.5-97.1% for Cu, 101.8-105.2% for Pb, and 94.1-97.3% for Sn; Recovery values for soil samples were 99.3-104.3% for Cu, 93.6-103.3% for Pb and 99.5-101.6% for Sn detected among them.

Evogliptin and Metformin are antidiabetic medications. Evogliptin works by increasing the release of insulin from the pancreas and decreasing the hormones that raise blood sugar levels. This reduces the fasting and post-meal sugar levels. Metformin works by lowering glucose production in the liver, delaying the absorption of sugar (glucose) from the intestines, and increasing the body's sensitivity to insulin. Accurate and precise high performance liquid chromatographic method has been developed for the estimation of Metformin and Evogliptin. Agilent C18 Column (250mm x 4.6mm, 5µm particle size) was used as stationary phase and methanol: 0.11% acetic acid in water (31: 69 % V/V) was used as mobile phase. The method was linear in the concentration range 50-250 µg/mL and 0.5 to 2.5 µg/mL of Metformin and Evogliptin respectively with a correlation coefficient of 0.999. The proposed method was validated with respect to linearity, accuracy, precision, and robustness as per International Council for Harmonisation of Technical Requirements of Pharmaceuticals for Human Use ICH Q2 (R2) guideline. The method was successfully applied for the analysis of Metformin and Evogliptin