Development and validation of an ultra-performance liquid chromatography method for simultaneous analysis of 20 antihistaminics in dietary supplements.

The purpose of this study was to develop and validate an ultra-performance liquid chromatography method for simultaneous analysis of 20 antihistamines (illegal additives) in dietary supplements. The limits of detection and quantitation of the method ranged from 1.5 to 2.5 µg/mL and from 20.0 to 50.0 µg/mL, respectively. The determination coefficient was >0.999, precisions were 0.2-5.1% (intra-day) and 0.1-8.8% (inter-day), and accuracies were 84.5-111.2% (intra-day) and 91.9-112.0% (inter-day). The mean recoveries of 20 targeted compounds from dietary supplements ranged from 75.4 to 119.3%. The relative standard deviations were <6.6% and complied with established international guidelines. The relative standard deviation of stability was <0.8%. Fifty-two commercially available dietary supplements were evaluated using this method, and were found to have none of the 20 antihistamines in significant abundance.

Analysis of 10 systemic pesticide residues in various baby foods using liquid chromatography-tandem mass spectrometry.

Ten systemic pesticides, comprising methomyl, thiamethoxam, acetamiprid, carbofuran, fosthiazate, metalaxyl, azoxystrobin, diethofencarb, propiconazole, and difenoconazole, were detected in 13 baby foods (cereals, boiled potatoes, fruit and milk) using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) for sample preparation and liquid chromatography tandem mass spectrometry for analysis. The matrix-matched calibration curves showed good linearity with determination coefficients (R(2) ) >0.992. The limits of detection and quantitation were 0.0015-0.003 and 0.005-0.01 mg/kg, respectively. The mean recoveries of three different concentrations ranged from 69.2 to 127.1% with relative standard deviations <20%. The method was successfully applied to 13 actual samples collected from a local market, and none of the samples were found to contain pesticide residues. This method is suitable for the identification and quantification of systemic pesticides with matrix-matched standards in various baby foods.

An analytical method for prohexadione in Chinese cabbage and apple.

A residual determination method as a regulatory residue method was developed using HPLC-UVD for prohexadione residues in Chinese cabbage (Brassica pekinensis) and apple (Malus domestica). The developed method consisted of solid-liquid extraction with acidic acetonitrile and ion-suppression liquid-liquid partitioning, followed by anion exchange cartridge cleanup. The limits of detection and quantitation for the method were 0.005 and 0.02 mg/kg, respectively. The method gave good linearity in the range of 0.02-2.5 mg/kg. Accuracy and precision ranged from 84.1 to 94.1% and from 2.4 to 6.9%, respectively. Additionally, the confirmative conditions of LC-MS/MS for prohexadione were set in negative electrospray ionization mode with transitions of m/z 211.4 → 167.5 and m/z 211.4 → 123.5 in the selected reaction monitoring mode. The applicability of the method was demonstrated by analyzing real samples collected from local markets in Seoul, Republic of Korea. This developed method fully deserves consideration in accordance with its sensitivity, accuracy and precision required for residue analysis of prohexadione in Chinese cabbages and apples.

Simultaneous multiresidue analysis of 41 pesticide residues in cooked foodstuff using QuEChERS: Comparison with classical method.

The principal objective of this study was to develop a simple multiresidue method involving a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method for the identification and quantification of 41 pesticide residues in cooked foodstuffs including cooked potatoes, radishes, and rice using GC-µECD. The analytes were subsequently confirmed via GC-MS. The results were then compared using the classical method established by the KFDA. The quantitation of individual pesticides was based on matrix-matched calibration curves with a correlation coefficient in excess of 0.993 for the 41 pesticides selected herein. Using QuEChERS, the mean recoveries ranged between 68.6 and 130.0% for the majority of the tested pesticides; however, the classical method exhibited low recoveries for dichlofluanid, tetraconazole, oxadixyl, fenbuconazloe, and paclobutrazol. After QuEChERS, the LODs and LOQs ranged between 0.004 and 0.3µg/kg and 0.0125 and 1.0µg/kg, respectively. The proposed method was applied successfully to determine the residue levels in cooked foodstuffs, and none of the samples contained detectable amounts of pesticide residues.

Collision-induced dissociation pathways of H1-antihistamines by electrospray ionization quadrupole time-of-flight mass spectrometry.

Over the past decades, mass spectrometry technologies have been developed to obtain mass accuracies of one ppm or less. Of the newly developed technologies, quadrupole time-of-flight mass spectrometry (Q-TOF-MS) has emerged as being well suited to routine and high-throughput analyses of pharmaceuticals. Dietary supplements and functional foods have frequently been found to be contaminated with pharmaceuticals. In our continuous efforts to develop methodologies to protect public health against adulterated dietary supplements, we have constructed a mass spectral database for 21 H1-antihistamines encountered as adulterants by using liquid chromatography-electrospray ionization (LC-ESI)/Q-TOF-MS, and have proposed their possible collision-induced dissociation pathways. This database will be very useful for the rapid and accurate detection of H1-antihistamines (known) and their analogues (unknown) illegally added to dietary supplements as well as in other sample matrices.

Reliable screening and confirmation of 156 multi-class illegal adulterants in dietary supplements based on extracted common ion chromatograms by ultra-high-performance liquid chromatography-quadrupole/time of flight-mass spectrometry.

An analytical method for the reliable screening and confirmation of 156 illegal drugs (58 erectile dysfunction drugs, 49 synthetic steroids, 26 anabolic steroids, and 23 anti-histamine drugs) in supplementary diets using ultra-high-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UHPLC-Q/TOF-MS) was developed. Various types of supplements (liquid, capsule, powder, pill and tablet) with complicated matrices were pretreated by simple liquid-liquid extraction. The wide scope of 156 target compounds was effectively determined within 15min in the positive ion mode, detecting the compounds at a sub-ppb level. Their MS/MS spectra were preferentially investigated to find diagnostic common ions according to the structural similarity of diverse adulterants. For the rapid screening of multiple classes of the target adulterants, extracted common ion chromatograms (ECICs) based on specific fragments of similar molecular moieties were attempted. A database including the elemental compositions, retention times, and MS/MS spectra was built for the confirmation of adulterants. The established method was validated in terms of the linearity, limits of detection (LOD), precision, and accuracy. The linear correlation coefficient and limit of detection ranged from 0.9880 to 1 and from 0.02 to 16.04ng/mL, respectively. The precision and accuracy of intra- and inter-day experiments for the spiked samples at the range of 0.2 and 16.0ng/mL were from 0.16 to 13.50% and 0.19-11.48%, respectively, with relative standard deviation. Mean recoveries ranged from 81.6 to 124.7%, and relative standard deviation was less than 9.20%. The screening and confirmation method demonstrated the usefulness of UHPLC-Q/TOF-MS combined with ECICs as a promising approach for the analysis of multi-class adulterants. Finally, the established method was successfully applied for the monitoring of several types of dietary supplements in routine analysis.

Dissipation kinetics, pre-harvest residue limits, and hazard quotient assessments of pesticides flubendiamide and fluopicolide in Korean melon (Cucumis melo L. var. makuwa) grown under regulated conditions in plastic greenhouses.

The dissipation kinetics, pre-harvest residue limits, and hazard quotient (HQ) assessments of the pesticides flubendiamide and fluopicolide were conducted for Korean melon (Cucumis melo L. var. makuwa) cultivated at two different sites. A single extraction and cleanup procedure was carried out using acetone (partitioned with dichloromethane) and amino solid-phase extraction cartridges, respectively. Residue analysis was performed by HPLC with ultraviolet detection. Both pesticides showed excellent linearity with correlation coefficients of 0.9999 and 0.9996 for flubendiamide and fluopicolide, respectively. The accuracy (expressed as recovery %) at three spiking levels was 92.0-103.6 and 82.8-105.3%, and the precision (expressed as relative standard deviation) was 1.7-3.4 and 2.7-5.3% for flubendiamide and fluopicolide, respectively. The initial residues of flubendiamide/fluopicolide were 0.326/0.376 and 0.206/0.298 mg/kg at sites 1 and 2, respectively. These amounts were substantially lower than the maximum residue limits (MRLs = 1 and 0.5 mg/kg for flubendiamide and fluopicolide, respectively) established by the Korean Ministry of Food and Drug Safety. The half-lives of flubendiamide were 5.8 and 6.5 days, and those of fluopicolide were 6.7 and 9.1 days at sites 1 and 2, respectively. The shorter half-lives were attributed to seasonal variations (higher temperatures) and enzymatic and metabolic profiling. The risk assessment HQs of flubendiamide were 0.217/0.249 on day 0, which decreased to 0.102/0.168 on day 5, and to 0.065/0.88 on day 10; the HQ values for fluopicolide were 0.029/0.042, 0.022/0.025, and 0.010/0.019 on day 0, day 5, and day 10, for sites 1/2, respectively. From this data, we concluded that the fruits could be consumed safely.

Simultaneous Analysis of Cannabinoid and Synthetic Cannabinoids in Dietary Supplements Using UPLC with UV and UPLC-MS-MS.

The primary purpose of this study was to develop and validate a method based on UPLC with UV and UPLC-MS-MS for the simultaneous analysis of different cannabinoids and synthetic cannabinoids in food as well as in herbal and dietary supplements. The limits of detection and quantitation of the method ranged from 0.1 to 0.3 and 0.3 to 0.9 µg/mL by UPLC with UV, respectively. The coefficient of determination was >0.999; the intra- and interday precision of the method were 0.1-3.7 and 0.9-4.1%, respectively. The intra- and interday accuracy were 94.8-103.1 and 98.3-100.9%, respectively. The mean recoveries of nine cannabinoids obtained from tablet samples ranged from 81.1 to 105.4%. The mean extraction recoveries of nine target cannabinoids obtained from various types of samples (tablets, capsules, powders, liquids, cookies and candies) ranged from 82.26 to 112.40%. The relative standard deviation (RSD) of the stability of the prepared sample solutions was <1.80%. Identification and quantification of the nine cannabinoids were accomplished by ion spray UPLC-MS-MS using multiple reaction monitoring. The UPLC-MS-MS method was validated for linearity (R(2) > 0.99); the precision was 0.1-4.0% (intraday) and 0.1-2.8% (interday), and the accuracy was 98.0-103.5% (intraday) and 97.1-103.2% (interday). The mean extraction recoveries of six types of samples were 82.2-114.5% and the RSD of stability was <6.54%, complying with the established international guidelines. The results indicated that the method can be used for rapid and accurate screening of cannabinoids present in food.

Identification and screening of a tadalafil analogue found in adulterated herbal products.

A tadalafil analogue was detected in an herbal product by high performance liquid chromatography-diode array detector (HPLC-DAD) with a similar chromatographic retention time to tadalafil. The compounds were separated using semi-preparative HPLC. The structure of the detected tadalafil analogue was elucidated by LC-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) and nuclear magnetic resonance (NMR) spectroscopy. A positive ion at m/z 404.1644 was detected by LC-Q-TOF/MS, corresponding to a molecular formula of C23H22N3O4. This unknown compound was identified as an analogue of tadalafil containing an additional methylene group and named homotadalafil. Homotadalafil was detected in 10 of 91 herbal products at concentrations of 0.058mgg(-1) to 8.735mgg(-1).

Determination of anabolic-androgenic steroid adulterants in counterfeit drugs by UHPLC-MS/MS.

Anabolic-androgenic steroids (AASs) have been illegally used in counterfeit drugs to improve the performance of athletes. In addition, AASs have been used for cosmetic purpose by non-athletes. To determine the presence of 26 AASs, an analysis method using ultra-liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and validated. The validated method was applied to 19 counterfeit drugs collected from the Internet and off-line markets during 2014. Nearly 50% (9/19) of the samples contained one of these 26 AASs. In addition, the concentration ranges of the AASs ranged from 0.09 to 119,228.57 mg/kg in the suspected samples. The determined AASs primarily consisted of testosterone and testosterone 17-propionate (26%) followed by boldenone (21%). These results indicate the adulteration of over-the-counter counterfeit drugs, and the continuous monitoring of counterfeit drugs or dubious dietary supplements containing anabolic steroids is warranted.