ASAP®: How it Works

Advion’s direct atmospheric solids analysis probe, otherwise known as ASAP®, permits chemists fast and reliable sample analysis of liquid and solid samples such as reaction mixtures, food samples, natural products and tablets.

LC/CMS Quantitation of Chloramphenicol in Milk Products

We demonstrate a cost-effective UHPLC/CMS method for the analysis of chloramphenicol in milk with a detailed discussion of sensitivity, linear response range, carryover and robustness using the Advion expression® Compact Mass Spectrometer (CMS) and Advion AVANT™ UHPLC System.

This application note was adapted from a poster that was presented at the 2019 ASMS Conference on Mass Spectrometry and Allied Topics in Atlanta, GA.

Fluorine-18 Labeled Fluorofuranylnorprogesterone ([18F]FFNP) and Dihydrotestosterone ([18F]FDHT) Prepared by “Fluorination on Sep-Pak” Method

National Institutes of Health

National Heart, Lung, and Blood Institute, National Cancer Institute

Abstract

To further explore the scope of our recently developed “fluorination on Sep-Pak” method, we prepared two well-known positron emission tomography (PET) tracers 21-[18F]fluoro-16α,17α-[(R)-(1′-α-furylmethylidene)dioxy]-19-norpregn-4-ene-3,20-dione furanyl norprogesterone ([18F]FFNP) and 16β-[18F]fluoro-5α-dihydrotestosterone ([18F]FDHT). Following the “fluorination on Sep-Pak” method, over 70% elution efficiency was observed with 3 mg of triflate precursor of [18F]FFNP. The overall yield of [18F]FFNP was 64–72% (decay corrected) in 40 min synthesis time with a molar activity of 37–81 GBq/µmol (1000–2200 Ci/mmol). Slightly lower elution efficiency (~55%) was observed with the triflate precursor of [18F]FDHT. Fluorine-18 labeling, reduction, and deprotection to prepare [18F]FDHT were performed on Sep-Pak cartridges (PS-HCO3 and Sep-Pak plus C-18). The overall yield of [18F]FDHT was 25–32% (decay corrected) in 70 min. The molar activity determined by using mass spectrometry was 63–148 GBq/µmol (1700–4000 Ci/mmol). Applying this quantitative measure of molar activity to in vitro assays [18F]FDHT exhibited high-affinity binding to androgen receptors (Kd~2.5 nM) providing biological validation of this method.

Analysis was performed by Select Ion Monitoring (SIM) and LC/MS using the Advion expression Compact Mass Spectrometer (CMS).

LC/CMS Quantitation of Chloramphenicol in Milk Products

We demonstrate a cost-effective UHPLC/CMS method for the analysis of chloramphenicol in milk with a detailed discussion of sensitivity, linear response range, carryover and robustness using the Advion expression® Compact Mass Spectrometer (CMS) and Advion AVANT™ UHPLC System.

This poster was presented at the 2019 ASMS Conference on Mass Spectrometry and Allied Topics in Atlanta, GA.

A New Light on Vitamin D in Obesity: A Novel Association with Trimethylamine-N-Oxide (TMAO)

Federico II University Medical School of Naples, University of Naples “Federico II”

Abstract

Vitamin D deficiency and obesity are two public health problems extensively exacerbated over the last years. Among the several mechanisms proposed to account for the complex interplay between vitamin D and obesity, one that has gained particular attention is related to the emerging role of obesity-related changes in gut microbiota and gut-derived metabolites, such as Trimethylamine-N-oxide (TMAO). Vitamin D deficiency and high circulating TMAO levels are associated with body weight and the severity of non-alcoholic fatty liver disease (NAFLD). Considering the link of obesity with vitamin D on the one hand and obesity with TMAO on the other hand, and the central role of the liver in both the vitamin D and TMAO metabolism, the aim of this cross-sectional observational study was first, to confirm the possible inverse association between vitamin D and TMAO across different body mass index (BMI) classes and second, to investigate if this association could be influenced by the presence of NAFLD. One hundred and four adult subjects (50 males and 54 females; 35.38 ± 7.49 years) were enrolled. The fatty liver index (FLI) was used as a proxy for the diagnosis of NAFLD. Vitamin D deficiency was found in 65 participants (62.5%), while 33 subjects (31.7%) had insufficient levels, and the remaining subjects had sufficient levels of vitamin D. Subjects with both vitamin D deficiency and FLI-NAFLD had the highest TMAO levels (p < 0.001). By stratifying the sample population according to the BMI classes, vitamin D levels decreased significantly along with the increase of plasma TMAO concentrations, with the lowest vitamin D levels and highest TMAO, respectively, in class III obesity. Vitamin D levels showed significant opposite associations with circulating levels of TMAO (r = −0.588, p < 0.001), but this association was no longer significant after the adjustment for FLI values. The highest values of TMAO were significantly associated with the severity of obesity (OR 7.92; p < 0.001), deficiency of vitamin D (OR 1.62; p< 0.001), and FLI-NAFLD (OR 3.79; p < 0.001). The most sensitive and specific cut-off for vitamin D to predict the circulating levels of TMAO was ≤19.83 ng/mL (p < 0.001). In conclusion, our study suggests that high TMAO levels are associated with vitamin D deficiency and NAFLD. Further studies are required to investigate if there is a causality link or whether all of them are simply the consequence of obesity.

Analysis was performed by LC/MS using the Advion expression® Compact Mass Spectrometer (CMS).

Anti-Trypanosomal Evaluation of Ximenia Americana Root Bark and Chromatographic-Mass Spectrometric Profile

Nigerian Institute for Trypanosomiasis, University of Jos, University of Yaoundé

Abstract

Medicinal plants are the richest bio-resource of drugs for traditional systems of medicine, modern medicines, food supplements, pharmaceutical intermediates and chemical entities for synthetic drugs. Human African Trypanosomiasis (HAT) is a challenging and deadly disease due to its complex epidemiology and clinical presentations.  This study was conducted to investigate anti-trypanosomal action of Ximenia americana root bark on Trypanosoma brucei brucei using various solvent extracts and to develop thin layer (TLC-MS) and liquid chromatography-mass spectrometric (LC-MS) profiles of the plant.  Soxhlet extraction was used to obtain acetone, 70% ethanol total extracts in addition to n-hexane, dichloromethane, ethyl acetate and methanol fractions by sequential extraction. The inhibitory activity of the various extracts was compared by testing against T. b. brucei using isometamidium chloride as standard drug. The most active extract was separated by solid-phase extraction (C18 stationary phase) to obtain fractions which were profiled by TLC-MS (+ESI) and LC-MS. It was observed that anti-trypanosomal activity of acetone (16.83% yield) and 70% ethanol (18.23% yield) were comparable. However, methanol extract exhibited the highest activity with 99.18%, 97.5% and 87.50% inhibition at 3 h incubation (room temperature) using 1000 µg, 500 µg and 250 µg concentrations respectively. The activities at 1000 µg for methanol extract and isometamidium chloride were comparable with 95% CI [-1.10, 1.77]. TLC-MS and LC-MS analyses suggested gallic acid, 2,3,4,5-tetrahydroxybenzoic acid, 2ʹ,5-dimethoxyflavone, quercetin, dihydroquercetin and sesquiterpene when compared with literature database. This study presents data that could be useful in standardisation and preparation of alternative medicine in the treatment of African trypanosomiasis.

Analysis was performed by TLC/MS using the Advion expression Compact Mass Spectrometer (CMS) and Plate Express TLC Plate Reader.

AVANT™ UHPLC/CMS Analysis of Casein Proteins in Milk

In this application note, the Advion Interchim Scientific® AVANT™ UHPLC/CMS system is used to analyze casein proteins in whole milk extract to separate and detect β-casein-B, -A1, and -A2, as well as K-casein and αs1-casein variants. This method is also suitable for a quick, relative quantitation of the β-casein-B, -A1, and -A2 variants in standards of β-casein.