Journal of Chemical Metrology
A scientific open access journal in the field of analytical chemistry and accreditation
Journal of Chemical MetrologyA scientific open access journal in the field of analytical chemistry and accreditation
Determination of secondary metabolites of Origanum vulgare subsp. hirtum and O. vulgare subsp. vulgare by LC-MS/MS
Secondary metabolites of solvent extracts of Origanum vulgare subsp. hirtum and O. vulgare subsp. vulgare were determined using liquid chromatography–mass spectrometry (LC-MS/MS). Curcumin was used as an internal standard. Rosmarinic acid was determined as the main compound of studied extracts together with other phenolic acid derivatives. In LC-MS/MS analyses, relative standard deviations (RSD %) ranged between 0.11-9.47. The correlation values were found to be greater than 0.97 for each investigated analyte.DOI http://doi.org/10.25135/jcm.33.20.04.1610 (DOI number will be activated after the manuscript has been available in an issue.) Keywords Origanum phenolic compounds LC-MS/MS method validation uncertainty assessment rosmarinic acid Available online: May 09, 2020 DETAILS DOWNLOAD PDF © ACG Publications. All rights reserved.
Rapid and easy method for simultaneous measurement of widespread 27 compounds in natural products and foods
Phenolic compounds are dietary bioactive compounds that are available in foods and beverages. They are produced by the plant and/or by the mushrooms, naturally. Some of the natural phenolic compounds were also used in dietary supplements in the pharmaceutical or food industries. For simultaneous analyses of phenolic compounds in one injection, a rapid and sensitive method was developed for twenty-seven natural compounds using reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with diode array detector (DAD). The linear gradient elution systems of 0.1% acetic acid-methanol were used, and the analyzing time was 61 minutes. The method was validated with linearity, relative error, reproducibility, LOD values. Relative standard deviation between (n = 7) within and between days for reproducibility is less than 10%, and relative error (or recovery) is less than 5%. The method exhibited excellent linearity (R2>0.999), good precision (RSD<6.1%), recovery (97.6–104.1%) and limits of detection (0.23–28.81 µg/m1) and quantification (1.62– 87.29 µg/m1). The detection of compounds was performed at 220 nm, 280 nm, and 330 nm. The developed method for the rapid determination of phenolic compounds using RP-HPLC can be used to identify the availability of these phenolic compounds in natural and commercial products.DOI http://doi.org/10.25135/jcm.38.20.03.1589 (DOI number will be activated after the manuscript has been available in an issue.) Keywords RP-HPLC phenolic compounds food dietary supplements natural products Available online: May 02, 2020 DETAILS DOWNLOAD PDF © ACG Publications. All rights reserved.
Importance of sample pretreatment step on the bacterial toxicity bioassay of ZnO nanoparticles
(Eco)toxicological assessment of engineered nanoparticles has largely restricted to laboratory conditions, and contribution to the environmental matrix mostly ignored. Thus, the lack of reflection of the environmental matrix makes it harder to evaluate the ecotoxicity of nanoparticles and its mechanism. Therefore, sample pretreatment has a vital role for appropriate (eco)toxicological assessment and reflection of the environmental matrix. The present study aims to investigate the effect of different sample pretreatment strategies on the (eco)toxicity of ZnO nanoparticles and its mechanism. For this purpose, three sample pretreatments and related bacterial bioassay procedure was examined. Moreover, the impact of the sample pretreatment on the toxicity mechanism was investigated using the physicochemical parameters of ZnO nanoparticles and antioxidant responses of bacteria. The results showed that the sample pretreatment affected the physicochemical properties of ZnO nanoparticles, inhibition level and inhibition pathway.DOI http://doi.org/10.25135/jcm.37.20.03.1583 (DOI number will be activated after the manuscript has been available in an issue.) Keywords Sample preparation nanoparticles bacterial bioassay matrix effect seawater Available online: May 02, 2020 DETAILS DOWNLOAD PDF © ACG Publications. All rights reserved.
Determination of dihydrocapsaicin adulteration in dietary supplements using LC-MS/MS
Adulteration of dietary supplements are serious threats to public health in all around of world. Nowadays, in order to obtain the intended effect from natural remedies, the adulteration of natural products via artificial or harmful chemicals are increasing. A rapid LC-MS/MS method for determination of capsaicin and dihydrocapsaicin in dietary supplements via Fortis C18 (150 x 3 mm; 3 µm) column at 25 °C was developed and validated in a mixture of mobile phase A (1 % formic acid solution and 0.1 % ammonium formate in water) and B (1 % formic acid solution and 0.1 % ammonium formate in methanol) with gradient program at a flow rate of 0.35 mL/min. The recoveries of developed methods weytre obtained in the range of % 95.4-106.3 for capsaicin and % 96.3-108.9 for dihydrocapsaicin. This study shows that synthetic compound dihydrocapsaicin is widely use in dietary supplements products for adulteration to increase the effects of product without any declaration.DOI http://doi.org/10.25135/jcm.36.20.01.1532 (DOI number will be activated after the manuscript has been available in an issue.) Keywords Capsaicin dihydrocapsaicin LC-MS/MS adulteration lose weight dietary supplements Available online: April 19, 2020 DETAILS DOWNLOAD PDF © ACG Publications. All rights reserved.