Development of an analytical method for the quantitative determination of multi-class nutrients in different food matrices by solid-phase extraction and liquid chromatography-tandem mass spectrometry using design of experiments.

A simple and rapid analytical method based on solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with the aid of design of experiments (DOE) approach was developed and validated for simultaneous determination of multi-class nutrients (water- and fat-soluble vitamins and flavonoids) in various food matrices (vegetables, fruits, and cereals). The factors affecting the SPE method were optimized using DOE tools. The separation was achieved in 13 min using the C18 column by gradient LC programme. The SPE-LC-MS/MS method was validated in terms of limit of detection (1.29-29.17 ng/g), linearity range (25-1000 ng/g), coefficient of determination (0.993-0.999) and recovery (72.53-104.24%) for multi-class nutrients in different food samples. Inter- and intra-day precision were evaluated and found to be within acceptable range. The developed method finds extensive application in the routine analysis of multi-class nutrients in various food matrices.

Development of a multiclass method to quantify phthalates, pharmaceuticals, and personal care products in river water using ultra-high performance liquid chromatography coupled with quadrupole hybrid Orbitrap mass spectrometry.

Rationale: The organic micropollutants such as phthalates, pharmaceuticals, and personal care products (PPPCPs) enter the surface water through various routes. The aim of this study is to develop a sensitive and efficient method to identify and quantify 26 PPPCPs found in river water with acceptable accuracy and precision using a liquid chromatograph hyphenated with quadrupole hybrid Orbitrap mass spectrometry (Q-Orbitrap-MS) in a single chromatographic run. Method: The organic micropollutants were extracted from river water by solid-phase extraction (SPE) using hydrophilic-lipophilic balance sorbent and analyzed using an ultra-high performance liquid chromatograph (UHPLC) equipped with C18 stationary phase for chromatographic separation. The targeted mass experiments were conducted in a Q-Orbitrap-MS system in positive and negative electrospray ionization mode. Results: The method was found to be linear in the concentration range of 1-125 ng/L with coefficient of determination lying in the range of 0.995-0.999. The method achieved limit of quantification in the range of 0.41-1.72 ng/L, and method recovery measured at three different concentrations was found to be in the range of 75-115%. Intra- and interday precision expressed as percent relative standard deviation was found to be <15%. Matrix effect was found to be in the range of 83.5-109.79%. The matrix match calibration was used for quantification of PPPCPs in river water sample. The method performance was evaluated by analyzing real samples collected from Ganga River, and the concentrations of 21 analytes were found to be in the range of 0.76-9.49 ng/L for pharmaceuticals, 1.49-8.67 ng/L for phthalates, and 0.9-7.58 ng/L for personal care products. Conclusions: The present method was found to be precise, sensitive, and rapid to determine 26 PPPCPs including phthalates in river water samples using SPE-UHPLC-Q-Orbitrap-MS.

Transformation of Santonin to a Naproxen Analogue with Anti-Inflammatory Activity.

Santonin, a natural product, was aromatized with molecular iodine as the catalyst. The new compound was characterized as ( S)-methyl-2-(7-hydroxy-5,8-dimethylnaphthalen-2-yl) propanoate (2) based on 2D NMR spectroscopic data. Structurally, compound 2 was highly similar to the anti-inflammatory drug naproxen. The new naproxen analogue had significant potency against cyclooxygenase 1 and 2 (IC50 = 31.0 and 66.1 µM, respectively).

Determination of organochlorine compounds in fish liver by ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of organic droplet coupled with gas chromatography-electron capture detection.

A simple and rapid method for the extraction of organochlorine compounds (OCs) including poly-chlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in fish liver using ultrasound assisted dispersive liquid-liquid microextraction based on the solidification of floating organic droplet (US-DLLME-SFO) was developed. For reducing the complexity of the matrix, the sample was pre-treated prior to microextraction. Factors affecting US-DLLME-SFO were optimized by using statistical design of experiment (DoE). The analysis was carried out by Gas Chromatography (GC) equipped with micro electron capture detector (µ-ECD). The optimized parameters were 4.8 min of ultrasound, 3.0 mL of Milli-Q and 24 µL of 1-undecanol as an extraction solvent as determined by DoE. US-DLLME-SFO was validated in terms of limit of detection, limit of quantification, dynamic linearity range, coefficient of determination (linearity) and extraction recovery in fish liver for OCs, and the respective values were (1.06-3.84 ng g-1), (3.50-12.67 ng g-1), (1.0-500 ng g-1), (R2 = 0.994-0.999), (88.5-108.4%). Interday and intraday precisions were evaluated as relative standard deviation (% RSD) and the values were ≤10%.

Comparison of two microextraction methods based on solidification of floating organic droplet for the determination of multiclass analytes in river water samples by liquid chromatography tandem mass spectrometry using Central Composite Design.

Two low density organic solvents based liquid-liquid microextraction methods, namely Vortex assisted liquid-liquid microextraction based on solidification of floating organic droplet (VALLME-SFO) and Dispersive liquid-liquid microextraction based on solidification of floating organic droplet(DLLME-SFO) have been compared for the determination of multiclass analytes (pesticides, plasticizers, pharmaceuticals and personal care products) in river water samples by using liquid chromatography tandem mass spectrometry (LC-MS/MS). The effect of various experimental parameters on the efficiency of the two methods and their optimum values were studied with the aid of Central Composite Design (CCD) and Response Surface Methodology(RSM). Under optimal conditions, VALLME-SFO was validated in terms of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery for which the respective values were (0.011-0.219ngmL-1), (0.035-0.723ngmL-1), (0.050-0.500ngmL-1), (R2=0.992-0.999), (40-56), (80-106%). However, when the DLLME-SFO method was validated under optimal conditions, the range of values of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery were (0.025-0.377ngmL-1), (0.083-1.256ngmL-1), (0.100-1.000ngmL-1), (R2=0.990-0.999), (35-49), (69-98%) respectively. Interday and intraday precisions were calculated as percent relative standard deviation (%RSD) and the values were ≤15% for VALLME-SFO and DLLME-SFO methods. Both methods were successfully applied for determining multiclass analytes in river water samples.

Ionic liquid based vortex assisted liquid-liquid microextraction combined with liquid chromatography mass spectrometry for the determination of bisphenols in thermal papers with the aid of response surface methodology.

A sensitive, rapid and efficient ionic liquid-based vortex assisted liquid-liquid microextraction (IL-VALLME) with Liquid Chromatography Mass spectrometry (LC-MS/MS) method is proposed for the determination of bisphenols in thermal paper. Extraction factors were systematically optimized by response surface methodology. Experimental factors showing significant effects on the analytical responses were evaluated using design of experiment. The limit of detection for Bisphenol-A (BPA) and Bisphenol-S (BPS) in thermal paper were 1.25 and 0.93µgkg-1 respectively. The dynamic linearity range for BPA was between 4 and 100µgkg-1 and the determination of coefficient (R2) was 0.996. The values of the same parameters were 3-100µgkg-1 and 0.998 for BPS. The extraction recoveries of BPA and BPS in thermal paper were 101% and 99%. Percent relative standard deviation (% RSD) for matrix effect and matrix match effects were not more than 10%, for both bisphenols. The proposed method uses a statistical approach for the analysis of bisphenols in environmental samples, and is easy, rapid, requires minimum organic solvents and efficient.

Vortex-assisted surfactant-enhanced emulsification microextraction combined with LC-MS/MS for the determination of glucocorticoids in water with the aid of experimental design.

An efficient and inexpensive method using vortex-assisted surfactant-enhanced emulsification microextraction (VASEME) based on solidification of floating organic droplet coupled with ultraperformance liquid chromatography-tandem mass spectrometry is proposed for the analysis of glucocorticoids in water samples (river water and hospital wastewater). VASEME was optimized by the experimental validation of Plackett-Burman design and central composite design, which has been co-related to experimental design. Plackett-Burman design showed that factors such as vortex time, surfactant concentration, and pH significantly affect the extraction efficiency of the method. Method validation was characterized by an acceptable calibration range of 1-1000 ng L-1, and the limit of detection was in the range from 2.20 to 8.12 ng L-1 for glucocorticoids. The proposed method was applied to determine glucocorticoids in river water and hospital wastewater in Lucknow, India. It is reliable and rapid and has potential application for analysis of glucocorticoids in environmental aqueous samples. Graphical Abstract Low density based extraction of gluococorticoids by using design of experiment.

Fast agitated directly suspended droplet microextraction technique for the rapid analysis of eighteen organophosphorus pesticides in human blood.

A new sample preparation technique named as fast agitated directly suspended droplet microextraction (FA-DSDME) was proposed as an improved version of directly suspended droplet microextraction (DSDME) for the extraction and pre-concentration of wide-range organophosphorus pesticides (OPPs) from human blood prior to liquid chromatography tandem mass spectrometric (LC-MS/MS) analysis. In this method, instead of protecting the unwanted rupturing of extraction droplet (organic solvent), it was deliberately splintered into fine droplets by providing automated high-speed agitation to the biphasic extraction system (extraction solvent and sample solution). Fine organic droplets were then recollected into one, not by using a centrifuge machine but just by giving a very slow stirring to the bottom of the extraction system. The present method has surmounted the problem of prolonged extraction time associated with old DSDME. Under optimum extraction conditions, the method showed good sensitivity with low detection limits ranging from 0.0009 to 0.122µgL(-1). Mean recoveries were achieved in the range of 86-109% at three levels of spiking concentration (low, middle and high) from linearity range of individual analyte. Intra-day and inter-day precisions were ≤4.68 and ≤9.57 (%RSD) respectively. Enrichment factor (EF) for each analyte varied from 30 to 132 which prove the ability of this technique to pre-concentrate the extracted analytes up to a good extent. The sample matrices have shown an insignificant influence on method's sensitivity. The proposed method may find immense use in epidemiological, toxicological, regulatory and forensic laboratories.