Determination of Menaquinone-7 by a Simplified Reversed Phase- HPLC Method

Ranmadugala, Dinali; Grainger, Megan N.C.; Manley‐Harris, Merilyn; Berenjian, Aydin

doi:10.2174/1389201019666180828090637

Cited by 11 publications

(5 citation statements)

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“…The regression coefficient for all calibration curves was greater than 0.999 (Figure 2a-d). The obtained results were better than those found in the literature, which considers that a regression coefficient above 0.99 is satisfactory [15][16][17][18][19][20][21][22][23]. The LOD and LOQ of the target analytes are presented in Table 2.…”

Section: Chromatographic Parametersmentioning

confidence: 63%

Simultaneous Determination of Vitamins D3 (Calcitriol, Cholecalciferol) and K2 (Menaquinone-4 and Menaquinone-7) in Dietary Supplements by UHPLC

et al. 2021

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The content and composition of dietary supplements is of great interest due to their increasing consumption and variety of available brand offered in the market. Accurate determination of vitamins is important for the improvement of dietary supplement quality and nutrition assessments. In this regard, the simultaneous determination of vitamin D3 (calcitriol—CT and cholecalciferol—CHL) and K2 (menaquinone-4—MK-4 and menaquinone-7—MK-7) in dietary supplements was developed by using ultra-high-pressure liquid chromatography (UHPLC). The overall runtime per sample was above 35 min, with the retention times of 2.40, 6.59, 7.06, and 32.6 min for vitamin D3 (CT and CHL) and vitamin K2 (MK-4 and MK-7), respectively. The limits of detection and limits of quantification for the target nutritional compounds ranged between 0.04–0.05 µg/mL, respectively. The validation results indicated that the method had reasonable linearity (R2 ≥ 0.9990), good recovery (>82%), satisfactory intra-day precision (≤1.9%) and inter-day precision (≤3.5%), and high selectivity and specificity. The validated UHPLC method was demonstrated to be precise, accurate, and robust for the simultaneous determination of vitamins D3 (CT and CHL) and K2 (MK-4 and MK-7) in dietary supplements.

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Section: Chromatographic Parametersmentioning

confidence: 63%

Simultaneous Determination of Vitamins D3 (Calcitriol, Cholecalciferol) and K2 (Menaquinone-4 and Menaquinone-7) in Dietary Supplements by UHPLC

et al. 2021

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“…For cellular fatty acid analysis, 60 mg of GB24 T and DB1506 T were harvested after cultivation on NA and Reasoner's 2A (R2A) agar (Beijing Coolaber Technology) plates at 37 °C for 72 h. Fatty acids were detected by gas chromatography and identified according to the manufacturer's protocol of the Microbial Identification System [8]. Isoprenoid quinones were extracted as described by Collins and analysed by reverse-phase high-performance liquid chromatography [9,10]. The pigments of GB24 T grown on NA agar plates were extracted with acetone/methanol (7 : 2, v/v) and their absorption spectra were measured at the range of 360-1000 nm (intervals of 10 nm) using a UV-visible spectrophotometer (Thermo Scientific).…”

Section: Chemotaxonomy Analysismentioning

confidence: 99%

Roseicella aerolata sp. nov., isolated from bioaerosols of electronic waste

Qin

Pan

Ren

et al. 2022

International Journal of Systematic and Evolutionary Microbiology

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A novel Gram-stain-negative, non-motile, spherical-shaped and facultatively anaerobic bacterial strain, designated as GB24T was isolated from bioaerosols of an E-waste dismantling site in Guiyu, Guangdong Province, South PR China. Growth occurred at 15–40 °C (optimum 37 °C), pH 5.5–9.5 (optimum 7.0), and up to 0.5 % NaCl (w/v) under aerobic conditions, GB24T was characterized taxonomically and phylogenetically. The sole isoprenoid quinone detected was ubiquinone-10 (Q-10). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, three unidentified glycolipids, one unidentified phospholipid, and one unidentified aminolipid. Carotenoid pigments were produced. The major cellular fatty acids (> 10 % of total fatty acids) were C17 : 1ω6c (51.5 %) and summed feature 8 (13.5 %, comprising C18 : 1ω7c and/or C18 : 1ω6c). Phylogenetic analysis based on 16S rRNA gene sequence and draft genome grouped strain GB24T into the genus Roseicella . GB24T was most closely related to Roseicella frigidaeris DB1506T with 97.5 % 16S rRNA gene sequence similarity. The draft genome of GB24T comprised 6 153 170 bp with a DNA G+C content of 71.5 %. The average nucleotide identity (ANI) and in silico DNA–DNA hybridization (isDDH) values between GB24T and DB1506T were 83.2 % (Ortho ANI), 83.3 % [ANI by blast (ANIb)] and 27.0 %, respectively. Further genomic analysis of GB24T revealed the secondary metabolite clusters of terpene and phosphonate, which indicate the capacity for malleobactin (14 %) and phosphinothricin (6 %) tripeptide production. On the basis of the genotypic, chemotaxonomic and phenotypic results, GB24T represents a novel species, for which the name Roseicella aerolata sp. nov. is proposed. The type strain of Roseicella aerolata is GB24T (= GDMCC 1.2169T = JCM 34449T).

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“…For example, a reliable assay for MK7 in plasma requires 94% recovery. 60 In addition, sensitivity is high, and the methods mentioned above have lower detection limits, ranging from 0.1 mg/ml to 0.03 ng/ml. 61,62 Of note, at present, there is no international gold standard for determining circulating vitamin K levels.…”

Section: Vitamin K Status: Biomarkersmentioning

confidence: 99%