Smartphone as a fluorescence detector for high-performance liquid chromatography.

BACKGROUND: Fluorescence detection is employed in high-performance liquid chromatography (HPLC) due to its high specificity and sensitivity. However, it is often limited by expensive components and bulkiness. Recently, advances in technology and electronics have led to the development of smartphones that can serve as portable recording, analysis, and monitoring tools. Smartphone-based detection provides advantages of cost effectiveness, rapid signal/data processing, and the display of results on a handhold monitor. The combination of smartphone-based detection with HPLC can offer unique features that are beneficial in overcoming limitations of commercial fluorescence detectors. (90) RESULTS: A miniaturized and low-cost HPLC fluorescence detector based on a smartphone is introduced for the detection of six fluorescent molecules. The smartphone is able to capture emitted fluorescence in video format while MATLAB code is used for data processing to provide chromatograms based on different detection channels. A custom designed double-channel flow cell was utilized to enable simultaneous detection of fluorescent compounds with different excitation wavelengths. The detector consists of a lab-made flow cell, monochromatic LEDs as the light source, 3D printed housing and connector box, fiber optic cables, and a smartphone. The effects of flow cell geometry, channel width and light slit diameter, as well as a comparison of different flow cell manufacturing techniques, are studied and discussed. The validated system was successfully applied to samples from diverse water sources, yielding spiking recoveries within the range of 91.7% and 109.7%. (141) SIGNIFICANCE: This study introduces the first smartphone-based fluorescence detector for HPLC with cost-effective and customizable flow cells, allowing for the simultaneous detection of fluorescent compounds with different excitation wavelengths and offering a potential solution for the analysis of co-eluting compounds. Beyond its user-friendly interface and low-cost, smartphone detection in HPLC provides tremendous opportunities in further miniaturizing chromatographic instrumentation while offering high sensitivity and can be expanded to other mechanisms of detection. (70).

Study of the Stability of Wine Samples for 1H-NMR Metabolomic Profile Analysis through Chemometrics Methods.

Wine is a temperature, light, and oxygen-sensitive product, so its physicochemical characteristics can be modified by variations in temperature and time when samples are either sampled, transported, and/or analyzed. These changes can alter its metabolomic fingerprinting, impacting further classification tasks and quality/quantitative analyses. For these reasons, the aim of this work is to compare and analyze the information obtained by different chemometric methods used in a complementary form (PCA, ASCA, and PARAFAC) to study 1H-NMR spectra variations of four red wine samples kept at different temperatures and time lapses. In conjunction, distinctive changes in the spectra are satisfactorily tracked with each chemometric method. The chemometric analyses reveal variations related to the wine sample, temperature, and time, as well as the interactions among these factors. Moreover, the magnitude and statistical significance of the effects are satisfactorily accounted for by ASCA, while the time-related effects variations are encountered by PARAFAC modeling. Acetaldehyde, formic acid, polyphenols, carbohydrates, lactic acid, ethyl lactate, methanol, choline, succinic acid, proline, acetoin, acetic acid, 1,3-propanediol, isopentanol, and some amino acids are identified as some of the metabolites which present the most important variations.

Batch Scale Production of 3D Printed Extraction Sorbents Using a Low-Cost Modification to a Desktop Printer.

This study reports a simple modification to a commercial resin 3D printer that significantly reduces the amount of prepolymer material needed for the production of extraction sorbents. The modified printing platform is demonstrated in the printing of two imidazolium-based ionic liquid (IL) monomers. Two geometries resembling a blade-type polymeric ionic liquid (PIL) sorbent used in thin-film microextraction and a fiber-type sorbent used in solid-phase microextraction (SPME) were printed. The SPME PIL sorbents were used to extract 10 organic contaminants, including plasticizers, antimicrobial agents, UV filters, and pesticides, from water followed by high-performance liquid chromatographic (HPLC) analysis. To compare the extraction performance of the SPME sorbents, seven fibers printed with the same prepolymer composition from the same printing batch as well as different batches were evaluated. The results revealed highly reproducible extraction efficiencies for all tested sorbents with no statistical difference in their extraction performance. Method validation showed acceptable linearity (R2 > 0.92) for all analytes with limits of detection and limits of quantification ranging from 0.13 to 45 µg L-1 and 0.43 to 150 µg L-1, respectively.

Multi-residue method to determine selected personal care products from five classes in fish based on miniaturized matrix solid-phase dispersion and solid-phase microextraction coupled to gas chromatography-mass spectrometry.

A method featuring matrix solid-phase dispersion combined with solid-phase microextraction coupled to gas chromatography-mass spectrometry was developed to determine parabens, musks, antimicrobials, UV filters, and an insect repellent in fish. Optimization and validation of the method was carried out on tilapia and salmon samples. Acceptable linearity (R2 > 0.97), precision (relative standard deviations < 13 %) and accuracy (recovery > 80 %) at two concentration levels for all analytes were obtained using both matrices. The limits of detection ranged from 0.01 to 1.01 µg g-1 (wet weight) for all analytes except for methyl paraben. The SPME Arrow format was applied to increase the sensitivity of the method, and yielded detection limits more than ten times lower than those achieved with traditional SPME. The miniaturized method can be applied to various fish species, regardless of their lipid content, and represents a useful tool for quality control and food safety purposes.

Isolation of DNA from plant tissues using a miniaturized matrix solid-phase dispersion approach featuring ionic liquid and magnetic ionic liquid solvents.

The isolation of high-quality plant genomic DNA is a major prerequisite in many plant biomolecular analyses involving nucleic acid amplification. Conventional plant cell lysis and DNA extraction methods involve lengthy sample preparation procedures that often require large amounts of sample and chemicals, high temperatures and multiple liquid transfer steps which can introduce challenges for high throughput applications. In this study, a simple, rapid, miniaturized ionic liquid (IL)-based extraction method was developed for the isolation of genomic DNA from milligram fragments of Arabidopsis thaliana plant tissue. This method is based on a modification of vortex-assisted matrix solid-phase dispersion (VA-MSPD) in which the trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide ([P6,6,6,14+][NTf2-]) IL or trihexyl(tetradecyl)phosphonium tris(hexafluoroacetylaceto)nickelate(II) ([P6,6,6,14+][Ni(hfacac)3-]) magnetic IL (MIL) was directly applied to treated plant tissue (∼1.5 mg) and dispersed in an agate mortar to facilitate plant cell lysis and DNA extraction, followed by recovery of the mixture with a qPCR compatible co-solvent. This study represents the first approach to use ILs and MILs in a MSPD procedure to facilitate plant cell lysis and DNA extraction. The DNA-enriched IL- and MIL-cosolvent mixtures were directly integrated into the qPCR buffer without inhibiting the reaction while also circumventing the need for additional purification steps prior to DNA amplification. Under optimum conditions, the IL and MIL yielded 2.87 ± 0.28 and 1.97 ± 0.59 ng of DNA/mg of plant tissue, respectively. Furthermore, the mild extraction conditions used in the method enabled plant DNA in IL- and MIL-cosolvent mixtures to be preserved from degradation at room temperature.

Analysis of persistent contaminants and personal care products by dispersive liquid-liquid microextraction using hydrophobic magnetic deep eutectic solvents.

In this work, hydrophobic magnetic deep eutectic solvents (HMDESs) were used in the development of a simple and rapid dispersive liquid-liquid microextraction (DLLME) approach coupled to high performance liquid chromatography with UV detection (HPLC-UV) for the determination of ten organic contaminants including five polycyclic aromatic hydrocarbons, four UV filters, and a pesticide from water at trace levels. The HMDESs were prepared by mixing a hydrogen bond acceptor, metal halide salt, and hydrogen bond donor in suitable molar ratios. Two HMDESs, 2 tetraoctylammonium bromide ([N8888+][Br-]): cobalt chloride (CoCl2): 4 octanoic acid (OA) and 3 trioctylphosphine oxide (TOPO): neodymium chloride (NdCl3): 3 OA, offered the highest analyte extraction efficiency overall and were chosen as suitable solvents for validation of the microextraction method. Under optimized extraction conditions, the method required 30 µL of HMDES as extraction solvent, acetone (87.5 µL) as disperser solvent, a NaCl concentration of 30% (w/v), and an extraction time of 120 s at 20°C. Enrichment factors of the analytes ranged from 44.6 for 3-(4-methylbenzylindene) camphor to 66.0 for 2-ethylhexyl-4-(dimethyl)aminobenzoate. The method provided low limits of detection (LODs) ranging from 0.5 to 4.5 µg L-1, and acceptable precision, with RSD values lower than 9.6%. Furthermore, the validated method was successfully applied for tap and lake water analysis, resulting in relative recoveries of spiked samples ranging between 94.7 and 119.2%.

An improved method for the determination of cannabidiol in topical products using ultrasound-assisted extraction and gas chromatography-mass spectrometry.

The recent surge in the sale of cannabidiol (CBD)-based topicals has risen rapidly in recent years, as it can be used to treat a multitude of skin disorders. However, there is minimal regulation concerning actual CBD content in these products. Topicals on the market may contain various concentrations of CBD and may be combined with a range of other compounds. The concentration of CBD has to be determined before the products enter the market. For this reason, a selective analytical method was developed using a 23 factorial design; and validated to determine CBD content in various topicals based on ultrasound-assisted extraction (UAE) followed by gas chromatography coupled to mass spectrometry (GC-MS). The method showed good precision (relative standard deviation ≤ 7.7%), accuracy at three concentration levels (recovery > 97.9%) for three different matrices, acceptable linearity (R2 > 0.99), and limit of detection (0.05 µg/mg). The method was successfully applied to the analysis of five commercial topicals. The proposed method is rapid, sensitive, precise, and accurate. In addition, it does not require derivatization and it is suitable for the determination of CBD in topicals for quality control purposes.

Recent advances in analysis of bisphenols and their derivatives in biological matrices.

Biomonitoring is a very useful tool to evaluate human exposure to endocrine-disrupting compounds (EDCs), like bisphenols (BPs), which are widely used in the manufacture of plastics. The development of reliable analytical methods is key in the field of public health surveillance to obtain biomonitoring data to determine what BPs are reaching people's bodies. This review discusses recent methods for the quantitative measurement of bisphenols and their derivatives in biological samples like urine, blood, breast milk, saliva, and hair, among others. We also discuss the different procedures commonly used for sample treatment, which includes extraction and clean-up, and instrumental techniques currently used to determine these compounds. Sample preparation techniques continue to play an important role in the analysis of complex matrices, for liquid matrices the most commonly employed is solid-phase extraction, although microextraction techniques are gaining importance in this field, and for solid samples ultrasound-assisted extraction. The main instrumental techniques used are liquid and gas chromatography coupled with mass spectrometry. Finally, we present data on the main parameters obtained in the validation of the revised methods. This review focuses on various methods developed and applied for trace analysis of bisphenols, their conjugates, halogenated derivatives, and diglycidyl ethers in biological samples to enable the required selectivity and sensitivity. For this purpose, a review is carried out of the most recent relevant publications from 2016 up to present.

Trace analysis of UV filters and musks in living fish by in vivo SPME-GC-MS.

A method was developed for the simultaneous determination of two groups of personal care products, namely UV filters (oxybenzone, 3-(4-methylbenzylidene)camphor, padimate-O, 2-ethylhexyl-4-methoxycinnamate, and octocrylene) and polycyclic aromatic musks (galaxolide and tonalide), in fish by in vivo solid-phase microextraction followed by gas chromatography-mass spectrometry. The in vivo method was validated by carrying out in vitro experiments; the method validation parameters were linearity (r2 > 0.98), interday precision (relative standard deviations < 35.50%), limits of detection and quantification ranging from 2 to 25 ng g-1 and 5 to 70 ng g-1, respectively. The calibrations in vivo and in vitro were determined using a pre-equilibrium sampling rate calibration method. In vivo sampling rate (Rs) was greater than that in vitro; therefore in vivo Rs was applied to the uptake and elimination tracing under controlled laboratory conditions to avoid quantitation error. All analytes were bioaccumulated in muscle tissue over the 5-day exposure in different grades depending on their molecular structure and physicochemical properties; the most absorbed compound was tonalide and the least absorbed compound was padimate-O. The elimination rate was initially high with a rapid decrease of the analyte concentrations for the first 24 h; thereafter, the rate of elimination tended to decrease which indicated that the target analytes were bioaccumulated. To our knowledge, this is the first time that UV filters have been analyzed with in vivo SPME-GC-MS. The proposed method is a simple, miniaturized, and non-lethal alternative for the determination of personal care products in living organisms. Graphical abstract.