A LC–MS/MS methodology to determine furaltadone residues in the macroalgae Ulva lactuca

Blue-emitting tryptophan-protected gold nanoclusters acted as a sensitive nanosensor for fluorescence sensing and visual imaging detection of furaltadone

Herein, blue-emitting gold nanoclusters (Au NCs) were carried out through tryptophan as the protecting and reducing agents. In aqueous solution of Au NCs@tryptophan, the addition of furaltadone guaranteed the interaction of furaltadone with tryptophan around Au NCs. The propinquity of furaltadone to Au NCs caused that the fluorescence of Au NCs was weakened by furaltadone based on the inner filter effect (IFE). Under the optimal measurement conditions, the logarithm of relative fluorescence intensity of Au NCs@tryptophan was linearly carried out with the furaltadone amount increasing from 0.5 to 100 μM, the corresponding detection limit was 0.087 μM. The fluorescence change of Au NCs@tryptophan displayed excellent selectivity and sensitivity for furaltadone than other possible substance in the human body. In view of Au NCs@tryptophan, the as-performed fluorescence nanosensor suggested outstanding ability for furaltadone sensing in real samples. Obviously, this nanoprobe of furaltadone could implement the naked-eye visual fluorescence determination of furaltadone.

Hierarchical 3D Snowflake-like Iron Diselenide: A Robust Electrocatalyst for Furaltadone Detection

An electrocatalyst with a large active site is critical for the development of a high-performance electrochemical sensor. This work demonstrates the fabrication of an iron diselenide (FeSe₂)-modified screen-printed carbon electrode (SPCE) for the electrochemical determination of furaltadone (FLD). It has been prepared by the facile method and systematically characterized with various microscopic/spectroscopic approaches. Due to advantageous physiochemical properties, the FeSe₂/SPCE showed a low charge-transfer resistance value of 200 Ω in 5.0 mM [Fe(CN)₆]^3-/4- containing 0.1 M KCl. More importantly, the FeSe₂/SPCE exhibited superior catalytic performance compared to the bare SPCE for FLD sensing based on the electrochemical response in terms of a peak potential of -0.44 V (vs Ag/AgCl (sat. KCl)) and cathodic response current of -22.8 μA. Operating at optimal conditions, the FeSe₂-modified electrode showed wide linearity from 0.01 to 252.2 μM with a limit of detection of 0.002 μM and sensitivity of 1.15 μA μM^-1 cm^-2. The analytical performance of the FeSe₂-based platform is significantly higher than many previously reported FLD electrochemical sensors. Furthermore, the FeSe₂/SPCE also has a promising platform for FLD detection with high sensitivity, good selectivity, excellent stability, and robust reproducibility. Thus, the finding above shows that the FeSe₂/SPCE is a highly suitable candidate for the electrochemical determination of glucose levels for real-time applications such as in human urine and river water samples.

One-step synthesis of blue emission copper nanoclusters for the detection of furaltadone and temperature

Polyvinyl pyrrolidone (PVP), playing roles as a templating agent, can be applied to prepare blue-emitting copper nanoclusters (Cu NCs@PVP) on the basis of a rapid chemical reduction synthesis method. The Cu NCs@PVP displayed a blue emission wavelength at 430 nm and the corresponding quantum yield (QY) could reach 10.4%. Subsequently, the as-synthesized Cu NCs@PVP were used for the trace analysis of furaltadone based on the inner filter effect (IFE) between Cu NCs@PVP and furaltadone, which caused the fluorescence to be effectively quenched. Additionally, this proposed determination platform based on the Cu NCs@PVP for furaltadone sensing possessed an excellent linear range from 0.5 to 100 μM with a lower detection limit of 0.045 μM (S/N = 3). Meanwhile, the Cu NCs@PVP also could be applied for the sensing of temperature. Furthermore, the practicability of the sensing platform has been successfully verified by measuring furaltadone in real samples, affirming its potential to increase fields for the determination of furaltadone.

Analysis of chloramphenicol residues in the macroalgae Ulva lactuca through ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS)

Antibiotic use is a well-described practice to promote animal health whether for prevention or treatment. Nonetheless, it can also cause a number of potentially harmful effects that dictate the need to implement regulation to assure a reduction of hazards to the consumers and the environment. Chloramphenicol (CAP) is a broad-spectrum antibacterial excluded from use in animal food production but despite this, reports of illegal use still persist. More recently, awareness has risen that the surrounding natural ecosystems can potentially be contaminated by pharmaceuticals and the extent of their effects in non-target organisms is already under the scope of researchers. To face the demanding new challenges a methodology for the determination of CAP in the green macroalgae Ulva lactuca by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) was developed, optimized and fully validated following the guidelines of the EC Decision 2002/657.

Sulfathiazole: analytical methods for quantification in seawater and macroalgae

The awareness of the interconnection between pharmaceutical residues, human health, and aquaculture has highlighted the concern with the potential harmful effects it can induce. Furthermore, to better understand the consequences more research is needed and to achieve that new methodologies on the detection and quantification of pharmaceuticals are necessary. Antibiotics are a major class of drugs included in the designation of emerging contaminants, representing a high risk to natural ecosystems. Among the most prescribed are sulfonamides, with sulfathiazole being the selected compound to be investigated in this study. In the environment, macroalgae are an important group of producers, continuously exposed to contaminants, with a significant role in the trophic web. Due to these characteristics are already under scope for the possibility of being used as bioindicators. The present study describes two new methodologies based on liquid chromatography for the determination of sulfathiazole in seawater and in the green macroalgae Ulva lactuca. Results show both methods were validated according to international standards, with MS/MS detection showing more sensitivity as expected with LODs of 2.79ng/g and 1.40ng/mL for algae and seawater, respectively. As for UV detection the values presented were respectively 2.83μg/g and 2.88μg/mL, making it more suitable for samples originated in more contaminated sites. The methods were also applied to experimental data with success with results showing macroalgae have potential use as indicators of contamination.

Identification of active compounds from Caesalpinia sappan L. extracts suppressing IL-6 production in RAW 264.7 cells by PLS

ETHNOPHARMACOLOGICAL RELEVANCE

Caesalpinia sappan L. is distributed in Southeast Asia and also used as herbal medicine for the treatment of various diseases such as burning sensations, leprosy, dysentery, osteoarthritis and rheumatoid arthritis (RA). The overproduction of IL-6 plays an important role in the prognosis of RA, but the active compounds from the extracts of Caesalpinia sappan L. suppressing IL-6 production remain unknown.

AIMS OF THE STUDY

Identifying the main active compounds of Caesalpinia sappan L. extracts inhibiting the IL-6 production in LPS-stimulated RAW 264.7 cells by partial least squares (PLS).

MATERIALS AND METHODS

Sixty-four samples with different proportions of compounds were prepared from Caesalpinia sappan L. by supercritical CO2 fluid extraction (SCFE) and refluxing. Each of 64 samples was applied to RAW 264.7 cells with LPS to evaluate whether IL-6 production by LPS is affected by addition of each sample. The IL-6 production in medium was determined by ELISA and the inhibitory activity of each sample was analyzed. In addition, the fingerprints of these 64 samples were also established by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-MS). We used the PLS, a simplified method, to evaluate the results from IL-6 production and fingerprints.

RESULTS

Each of 64 samples markedly suppressed LPS-induced IL-6 production in RAW cells. The fingerprints by UPLC-MS clearly revealed variations among 64 samples produced in different extract conditions. The PLS analysis with IL-6 production and fingerprints by UPLC-MS suggested that the peaks 71, 93, 150, 157, 168 have more influence on the inhibitory activity of Caesalpinia sappan L. extracts. The peaks 71, 93, 150 are likely representing sappanone A, protosappanin E and neoprotosappanin, respectively. The peaks 157 and 168 are still at large.

CONCLUSION

This is the first report that sappanone A, protosappanin E, neoprotosappanin and two unidentified compounds can be considered as possible active compounds that might inhibit IL-6 production. Further studies are needed to confirm the effectiveness of these five compounds on IL-6 production and possible mechanism.