Determination of four paraben-type preservatives and three benzophenone-type ultraviolet light filters in seafoods by LC-QqLIT-MS/MS.

For the first time, an efficient and sensitive analytical method based on liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry (LC-QqLIT-MS/MS) was developed for the simultaneous determination of four paraben-type preservatives and three benzophenone-type ultraviolet light filters in both plant (Sargassum fusiforme, porphyra, kelp) and animal (hairtail, yellow croaker, shrimp) seafood. The samples were extracted in methanol by pressurized liquid extraction (PLE), and the extracts were then cleaned up by mixed-mode cationic exchange (MCX) solid-phase extraction cartridges. Both isotope-labeled internal standards and matrix-matched calibration standards were used to alleviate and correct for the matrix effects, and the limits of quantification (LOQs) were 10.0µg kg(-1) for all target compounds. The average recoveries were in the range of 80.6-107.8% at three spiked concentration levels (10, 50 and 100µgkg(-1)) with relative standard deviations (RSDs) below 8.5%. The results suggest that very limited contamination of these seven emerging contaminants, mainly associated with PCPs, occurred in these common seafoods.

Rapid Quantification of Four Anthocyanins in Red Grape Wine by Hydrophilic Interaction Liquid Chromatography/Triple Quadrupole Linear Ion Trap Mass Spectrometry.

The identification and quantification of four anthocyanins (cyanidin-3-O-glucoside, peonidin-3-O-glucoside, delphinidin-3-O-glucoside, and malvidin-3-O-glucoside) in red grape wine were carried out by hydrophilic interaction liquid chromatography/triple quadrupole linear ion trap MS (HILIC/QTrap-MS/MS). Samples were diluted directly and separated on a Merck ZIC HILIC column with 20 mM ammonium acetate solution-acetonitrile mobile phase. Quantitative data acquisition was carried out in the multiple reaction monitoring mode. Additional identification and confirmation of target compounds were performed using the enhanced product ion mode of the linear ion trap. The LOQs were in the range 0.05-1.0 ng/mL. The average recoveries were in the range 94.6 to 104.5%. The HILIC/QTrap-MS/MS platform offers the best sensitivity and specificity for characterization and quantitative determination of the four anthocyanins in red grape wines and fulfills the quality criteria for routine laboratory application.

[Simultaneous determination of monosaccharide and oligosacpharide in rice wine by high performance anion exchange chromatography with integrated pulsed amperometric detection and the establishment of their fingerprints].

An analytical method for the determination of glucose, fructose, isomaltose, isomaltotriose, maltose, panose and maltotriose was developed by high performance anion exchange chromatography coupled with integrated pulsed amperometric detection. The analysis was performed on a CarboPa™ 10 column with gradient elution of NaOH-NaOAc as mobile phases. The seven sugars were well separated in less than 26 min and showed good linear correlation coefficients between 0.5 and 50 mg/L. The detection limits (LODs) were 0.1 g/L. The recoveries ranged from 76.5% to 108.4% at different spiked levels. The relative standard deviations were between 3.02% and 8.23%. The established method was applied in determining the seven sugars in different batches of Shaoxing Jiafan rice wines from different manufacturers. The standard fingerprints were established by median values using the obtained results. Similarities of the fingerprints of the samples to the standard were calculated by using angle cosine. The results showed that the similarities of wines from different manufacturers were significantly different, so the method could be used for the identification of rice wines from different manufacturers.

[Determination of four alkaloids in Corydalis decumbens by HPLC].

OBJECTIVE: To establish a quantitative HPLC method for determination of protopine, palmatine hydrochloride, bicuculline and tetrahydropalmatine, in Corydalis decumbens. METHOD: The separation was performed on a ZORBAX Eclipse XDB-C18 column (4.6 mm x 150 mm, 5 microm) at a flow rate of 1.0 mL x min(-1) using mixtures of two solvents [A(20 mmol x L(-1) ammonium acetate)-B(acetonitrile)]: with a gradient elution. The column oven temperature was 30 degrees C and the detection wavelength was set at 280 nm. RESULT: The 4 alkaloids were well separated by this HPLC method. Linearifies of protopine, palmatine hydrochloride, bicuculline and tetrahydropalmatine were good in the ranges of 1.44-46.0 (r = 0.999 4), 1.2640.2 (r = 0.999 8), 1.37-44.0 (r = 0.999 9), and 1.3643.6 mg x L(-1) (r = 0.999 9), respectively. The average recoveries were 98.2% with RSD 2.7% for protopine, 101.9% with RSD 2.5% for palmatine hydrochloride, 102.8% with RSD 3.5% for tetrahydropalmatine, and 98.8% with RSD 3.1% for tetrahydropalmatine. CONCLUSION: This method is proved to be convenient, reliable and accurate., and it can be used for quality control of C. decumbens.

[Simultaneous determination of four alkaloids in Corydalis decumbens (Thunb.) Pers. by high performance liquid chromatography-tandem mass spectrometry].

A method for the analysis of 4 alkaloids in Corydalis decumbens (Thunb.) Pers. was developed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-MS/MS). The sample was extracted in methanol by ultrasonic, filtered and diluted with methanol for further analysis. The analysis was performed on a C18 column (150 mm x 2.1 mm, 3.5 microm) using a gradient elution program with the mobile phase of 0.2% acetic acid solution and acetonitrile. The analyte was determined by an electrospray ionization tandem mass spectrometry in multiple reactions monitoring (MRM) mode. The qualitative and quantitative analyses were based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions of the analyte. The limits of detection (LODs) for 4 alkaloids were in the range of 0.02 - 0.2 microg/L, and the limits of quantification (LOQs) were in the range of 0.07 - 0.66 microg/L. The average recoveries were in the range of 93.6% - 103.5% for 4 alkaloids with the relative standard deviations below 3.8%. This method is reliable, sensitive and reproducible, and it can be used for the quality control of Corydalis decumbens (Thunb.) Pers. sample.

Microwave-assisted extraction and determination of cyanuric acid residue in pet food samples by liquid chromatography-tandem mass spectrometry.

Cyanuric acid (CYA) is attracting more attention due to its potential toxicity. In the present work, microwave-assisted extraction method in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was proposed for the determination of CYA in pet food samples. Among different solvents, diethylamine-acetonitrile-water mixture (1:5:4, v/v) was found to be the best one as the extractant due to the strong polarity of CYA in the pet food. An internal standard, (13) C(3) -labeled CYA, was used in the extractions. The separation was performed on a MERCK ZIC HILIC column (150 mm × 2.1 mm id, 5 µm) with gradient elution of 20 mM ammonium acetate solution-acetonitrile. CYA was well retained (Rt = 5.10 min) and eluted with good peak shape. The method could respond linearly with CYA at concentrations from 1.0 to 50 ng/mL with a quantification limit of 0.25 mg/kg. The intra- and inter-day precision was less than 4.0% and the recovery of the assay was in the range of 90.4-108.1%. In the analysis of practical spiked pet food samples, the new method yielded satisfactory results. Due to its simplicity and accuracy the straightforward method is particularly suitable for routine CYA detection.

Microwave-assisted extraction and determination of cyanuric acid residue in infant formula samples by liquid chromatography-tandem mass spectrometry.

In the present work, microwave-assisted extraction method in combining with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was proposed for the determination of cyanuric acid (CYA) in infant formula samples. The separation was performed on a MERCK ZIC HILIC column (150×2.1mm i.d., 5µm) with gradient elution of 20mM ammonium acetate solution - acetonitrile. The method could respond linearly with cyanuric acid at concentrations from 1.0 to 50ngmL(-1) with a quantification limit of 0.25mgkg(-1). The intra- and inter-day precision was less than 4% and the recovery of the assay was in the range of 86.7-93.1%. In the analysis of practical spiked infant formula samples, the new method yielded satisfactory results. Due to its simplicity and accuracy the straightforward method is particularly suitable for routine cyanuric acid detection.