Physicochemical analysis of Tigray honey: An attempt to determine major quality markers of honey

Ethanol is a common psychoactive substance that has been widely consumed in several parts of the world. Gas chromatography (GC) coupled with flame ionisation detector (FID) has often been used for the determination of blood alcohol concentration. The aim of this study was to develop and validate a very simple and reliable HS-GC-FID method for quantitative determination of ethanol in blood sample. Validation of the method was performed by means of Bias, Linearity, LOD, Selectivity, Specificity, Precision, Robustness and Intermediate precision. The method showed an excellent linearity with correlation coefficient (r² = 0.993) was observed in the range from 0.1 to 3.5 mg/mL of ethanol. The percent recovery value were between 91.0 and 109.1 which was with an acceptable percent recovery, The precision (repeatability) was reported as 27 % and intermediate precision of the method resulted in 11% and 1 % for two analysts. The limit of detection (LOD) of ethanol was calculated as 0.099 mg/mL and the selectivity of the method for interferents (methanol and acetaldehyde) was totally selective. Generally, the results obtained confirmed that the method is relatively fast, precise, simple, robust and can be used in routine forensic analyses for the determination of blood alcohol concentration (BAC) at a concentration level greater than 0.13 mg/mL.

For the determination of 15 potentially toxic elements (V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sn, Hg, and Pb) in plant and sediment samples of the Akaki River, Ethiopia, inductively coupled plasma–mass spectrometry, inductively coupled plasma–optical emission spectrometry, and a RA-915+ mercury analyzer were applied. Sediment and plant samples were mineralized using a closed-vessel microwave-assisted digestion system. The elemental concentrations varied considerably in plant and sediment samples. The minimum concentration was observed for known toxic elements (As, Hg, and Cd) while the highest concentration was observed for the elements of relatively low toxicity Zn, Mn, and Fe. The concentration of Cr, Fe, Pb, Zn, and As in Swiss chard surpassed the maximum permissible levels at specific sites. At some of the sites, the sediment quality guidelines are surpassed for Cu, Zn, and Pb.

Two selective and sensitive reagents, 2-acetylpyridine thiosemicarbazone (2-APT) and 3-acetylpyridine thiosemicarbazone (3-APT) were used for the spectrophotometric determination of Cu(II). Both reagents gave yellowish Cu(II) complex at a pH range of 8.0–10.0. Beer’s law was obeyed for Cu(II)–2-APT and Cu(II)–3-APT in the concentration range of 0.16–1.3 and 0.44–1.05 µg/mL, respectively. The molar absorptivity and of Cu(II)–2-APT and Cu(II)–3-APT were 2.14 × 104 at 370 nm, and 6.7 × 103 L/mol cm at 350 nm, respectively, while the Sandell’s sensitivity were 0.009 and 0.029 µg/cm2 in that order. The correlation coefficient of the standard curves of Cu(II)–2-APT and Cu(II)–3-APT were 0.999 and 0.998, respectively. The detection limit of the Cu(II)–2-APT and Cu(II)–3-APT methods were 0.053 and 0.147 µg/mL, respectively. The results demonstrated that the procedure is precise (relative standard deviation <2 %, n = 10). The method was tested for Cu(II) determination in soil and vegetable samples. Comparisons of the results with those obtained using a flame atomic absorption spectrophotometer for Cu(II) determination also tested the validity of the method using paired sample t test at the 0.05 level showing a good agreement between them.

Adsorption is alternative technique for recovery of nutrient resources with no/less secondary pollution. PNC adsorbents are effective for removal and recovery of nutrient resources, and reusing nutrients as fertilizer could prevent eutrophication.