A method was established for the determination of amitraz (AMZ), and its metabolites semiamitraz (DMPF), 2,4-dimethylformamidine (DMF) and 2,4-dimethylaniline (DMA) in vegetables and fruits by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The samples were diluted with 0.1 mol/L sodium hydroxide and extracted with n-hexane-isopropanol (2:1, v/v). The separation was performed on a Phenomenex Kinetex C18 column (100 mm×4.6 mm, 2.6 μm) with gradient elution using 0.1% (v/v) formic acid aqueous solution-methanol as the mobile phase. The analysis of amitraz and its metabolites were detected under electrospray positive ionization mode. The limits of quantification (LOQs) were between 0.01 and 0.4 μg/kg. The good linearities (r>0.99) were achieved for the target compounds in the range of 1.0-200.0 μg/L. The recoveries at three spiked levels (0.5, 5.0 and 20 μg/kg) in blank matrix were in the range of 62.5%-105.0% with the relative standard deviations between 7.5% and 17.6%. The method is convenient, rapid, accurate, efficient, sensitive and practical. It is suitable for the determination and confirmation of amitraz and its metabolites in vegetables and fruits, and can meet the demands of domestic and foreign regulations.
A method is proposed for the simultaneous determination of nine benzimidazole and neonicotinoid pesticides present in honey by employing automatic solid-phase extraction with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A honey sample was dissolved in a phosphate buffer (pH=7.8) followed by ultrasonic extraction. The extracts were then purified through solid-phase extraction (SPE) with hydrophilic-lipophilic balance (HLB) cartridges. Finally, nitrogen was blown on the obtained mixture, and the mixture was subsequently filtered for conducting HPLC-MS/MS analysis. Nine compounds were detected under the multiple reaction monitoring (MRM) mode, and the corresponding quantification was performed by employing the method of internal standards. The nine detected pesticides demonstrated good linearity in the range of 0.002-0.05 mg/L, with the correlation coefficient values (r2) being higher than 0.99. The limits of detection (LODs) (S/N=3) and limits of quantification (LOQs) (S/N=10) were found to be in the ranges of 0.1-1.0 μg/kg and 0.3-2.0 μg/kg, respectively. Furthermore, the results indicated that the recoveries of the nine detected pesticides range from 78.2%-101.2% at three spiked levels of 5.0, 10.0, and 20.0 μg/kg with a relative standard deviation (RSD) range of 1.3%-14.3% (n=6). Hence, the proposed method is rapid and can be employed for accurate determination of pesticide residues in large quantities of honey samples.
A method has been developed for rapid untargeted screening and determination of unknown contaminants in aquatic products by high performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry. The samples were extracted by acetonitrile, dried under nitrogen, dissolved in methanol-water (3:7, v/v), and analyzed via the full MS scan/data dependent MS2 mode during the screening process. The Trace Finder software was used to match the precise mass, the isotope abundance ratio, the fragment ion to search for unknown contaminants in aquatic samples. The optimized QuEChERS method is used to purify the samples when quantifying. The quantitative analyses of triazole, caffeine, and ethoxyquinoline were performed via the target-MS2 mode. The correlation coefficients of the three compounds in fish and shrimp samples were higher than 0.99 in the linear range of 5-1000 μg/L. The limit of detection was 1 μg/kg, and the limit of quantitation was 5 μg/kg. The average recoveries were between 70.5% and 90.9% with the relative standard deviations ranging from 5.4% to 12.8%. The screening method has the advantages of fast, accurate, and high throughput; when combined with the quantitative method, it can be used to screen and determine unknown contaminants in the actual aquatic products.
For the determination of organo-tin residues in edible vegetable oil, a method was developed based on gas chromatography-mass spectrometric (GC-MS) with positive chemical ionization (PCI). The edible oil samples were first dissolved by cyclohexane-ethyl acetate (1:1, v/v), and then purified by gel permeation chromatography (GPC). After derivatization by sodium tetraethylborate, the samples were analyzed by GC-MS with PCI source in the single ion monitor (SIM) mode. The seven organo-tin compounds showed good linear relationships in the range of 20-2000 μg/L and the correlation coefficients exceeded 0.99. The limits of quantitation (LOQs) and the average recoveries of the seven organo-tin compounds were 0.3-1.2 μg/kg and 66.2%-103.2%, respectively, and the relative standard deviations were less than 11.5% at three spike levels (0.05, 0.10, and 0.20 mg/kg). The method showed good linearity and high sensitivity and can be used for the determination of organo-tin residues in edible vegetable oil.
A method was established for the determination of five acylpyrazole pesticide residues in edible vegetable oils using gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS). The pesticides were extracted from a sample with acetonitrile under freezing conditions. A simple cleanup step known as QuEChERS was then conducted. After being identified by GC-NCI-MS, the extracts were quantified using an external standard method that employs a matrix correction standard curve. The linearity of the method was good between 20 and 1000 μg/L, and all limits of quantification were less than 2 μg/kg. Recoveries of all pesticides were in the range of 82.7%-112.4% at the three spiked levels of 0.01, 0.02, and 0.05 mg/kg, and all relative standard deviations were not more than 12.3%. Therefore, this method can be used to determine the residues of acylpyrazole pesticides in edible vegetable oils.
A method was developed for the simultaneous determination of 10 perfluorinated carboxylic acid compounds in water by gas chromatography-mass spectrometry coupled with negative chemical ionization (GC-NCI-MS). Perfluorinated carboxylic acid compounds were derivatized by trifluoro-N-methyl-N-(trimethylsilyl) acetamide (MSTFA) as the trimethylsilyl derivatization reagent. The water sample was purified and enriched through a weak anion exchange solid phase extraction column and analyzed via GC-NCI-MS. The sample pretreatment, derivation and instrument conditions were optimized. The results showed that the linearity of the 10 perfluorinated carboxylic acid compounds was good in the range of 0.1-10 mg/L with correlation coefficients of 0.9956-0.9993. The limits of detection (LODs) and limits of quantification (LOQs) were 0.5-1.5 μg/L and 1.5-4.5 μg/L, respectively. The spiked recoveries of the blank samples ranged from 70.2% to 112.6% with the relative standard deviations (RSDs) between 2.1% and 14.5% (n=6). The method is simple, sensitive, accurate and precise, and can be used to detect the 10 perfluorinated carboxylic acid compounds in water.
High-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (HPLC/Q-TOF MS) was used to analyze 23 phenolic compounds in Chinese poplar propolis, Brazil green propolis, and poplar gum. Propolis and poplar gum samples were dissolved in methanol-water (1:1, v/v) and filtered by 0.45 μm organic phase filtration membrane. The separation was carried out in an Agilent Eclipse Plus C18 column with gradient elution using acetoni-trile and 0.1% (volume percentage) formic acid solution as the mobile phases. The compounds were detected using positive ion electrospray ionization in full scan mode (m/z 100-1000). The quantification analysis was performed by the external standard method. The results showed that all the compounds were linear, with correlation coefficients>0.99, in the range of 10-20 μg/L. The limits of detection and limits of quantification for tangeretin and formononetin were 0.2 and 1 μg/L, respectively, and those for the other compounds were 2 and 10 μg/L, respectively. At the spiked levels of 10, 25, and 50 mg/kg, the recoveries of all the compounds ranged from 70.2% to 122.6%, with relative standard deviations of less than 10%. Salicin, cinnamic acid, caffeic acid, and coumaric acid could be used as markers for detecting adulteration in Chinese poplar propolis, while caffeic acid, ferulic acid, chrysin, caffeic acid phenethyl ester, pinocembrin, galangin, coumaric acid, isorhamnetin, kaempferide, and arte-pillin C could be used as markers for identifying Chinese poplar propolis and Brazil green propolis. The results presented in this paper may be helpful in quality control of propolis products.
A method was established for the determination of 50 kinds of antibiotic residues (macrolides, quinolones, sulfonamides, tetracyclines, nitroimidazoles, lincomycin and chloramphenicol) in drone pupa powder by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with perchloric acid and lead acetate solution, and the protein was precipitated. The extraction solution was adjusted to pH 8 using dipotassium hydrogen phosphate, then the solution was purified by solid phase extraction (SPE) and analyzed by LC-MS/MS. The target compounds in the drone pupa powder were determined quantitatively and quantitatively by using multiple reaction monitoring and positive ion or negative ion modes. The recoveries of the 50 antibiotics were in the range of 70.2%-118.3%, and the relative standard deviations (RSDs) were 1.8%-13.6%. The method is simple, selective, and can be suitable for the analysis and confirmation of veterinary drug residues in drone pupa powder.
Gas chromatography-mass spectrometry (GC-MS) is currently the most technical approach for the analysis of human body odor, which can be used to determine the composition of human body odor and compare the differences between different individual odors. This paper focuses on the application progress of GC-MS in human body odor analysis. First, the extraction and sample pretreatment of human body odor are briefly introduced. The applications of the human body odor analysis by GC-MS in collection and storage, the composition analysis and study of difference, and individual identification and health characterization are summarized. Finally, the application trends of GC-MS in human body odor analysis are discussed.
γ-Al2O3 nanoparticle-bonded graphene oxide (γ-Al2O3-GO) was prepared for use as a solid phase extraction absorbent and for preconcentration of four nucleosides in human urine samples for investigation by high-performance liquid chromatography (HPLC). Transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the absorbent. Several parameters (eluent species, absorbent amount, sample volume, and sample pH) were optimized, and the absorption efficiency was determined based on equilibrium absorbent amounts. Under optimal conditions, the γ-Al2O3-GO absorbent displayed enhanced absorbent ability for nucleosides. The calibration curve showed good linearities in the range of 0.10-10 mg/L for cytidine, inosine, and guanosine, and 0.05-10 mg/L for uridine; the correlation coefficient was observed to be in the range of 0.9967-0.9973. The limits of detection for the four nucleosides were in the range of 0.010-0.021 mg/L. Intra-day and inter-day relative standard deviations were 0.1%-0.8% and 1.0%-3.1%, respectively. The recoveries of the four nucleosides in urine samples ranged from 71.3% to 107.4%, and the relative standard deviations (n=3) were less than 4.8%. The results demonstrated that the proposed method is faster, more sensitive, and more efficient. Therefore, solid phase extraction (SPE)-based γ-Al2O3-GO can be considered more suitable for the determination and enrichment of nucleosides in urine samples.
Acute blood stasis syndrome was induced in rats by adrenaline hydrochloride and ice water. Ultra performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was conducted on plasma metabolites of normal and model rats. Principal component analysis (PCA), differentiation analysis of supervised partial least squares method (PLS-DA), and orthogonal to partial least squares discriminant analysis (OPLS-DA) on metabolomics data for multidimensional statistical analysis were employed, and the resulting biomarkers were screened. Compared to the normal group, there were 46 endogenous metabolites in blood stasis-rat plasma. Of these, 21 metabolites were significantly upregulated, such as acetylcholine, N6,N6,N6-trimethyl-L-lysine, cytosine, and acetylcarnitine, while 25 metabolites were reduced, including indoleacrylic acid, and lysoPC(14:0). These metabolites were mainly related to metabolic pathways, including lipid metabolism, galactose metabolism, linoleic acid metabolism, biosynthesis of unsaturated fatty acids, glycolysis, and arachidonic acid metabolism. In conclusion, these results indicated that metabolites could be used as important biomarkers for blood stasis syndrome, and could help in revealing the mechanism of blood stasis disease and provide a reference network to determine the disease development stage and appropriate follow-up treatment. Studying altered metabolites in blood stasis model rats can provide insights useful for the diagnosis of blood stasis in the clinic and for the development of drug therapies.
This study was performed to develop an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to detect and quantify morphine and 6-monoacetylmorphine in putrefied blood for forensic toxicological purposes. A modified QuEChERS method was implemented as follows:extraction of morphine and 6-monoacetylmorphine from putrefied blood was performed with an acetonitrile-water (4:1, v/v) mixture, and 30 mg NaCl and 60 mg anhydrous MgSO4 were subsequently added as salting out agents to induce phase separation. The supernatant was cleaned by adding 25 mg primary secondary amine sorbent (PSA) and 25 mg anhydrous MgSO4. Separation of the target compounds was performed using a ZORBAX Eclipse Plus C18 column by UPLC over a 4 min gradient elution where 0.01% (v/v) ammonium hydroxide buffer (A) and acetonitrile (B) were used as the mobile phase. MS/MS was used in positive electrospray ionization (ESI+) mode and multiple-reaction monitoring (MRM) was performed to detect the target drugs. This method achieved satisfactory recoveries (R) for morphine and 6-monoacetylmorphine with mean recovery values ranging from 81.84% to 103.44% and 81.03% to 104.46% respectively. The developed method also provided efficient purification of the sample from endogenous interferences with matrix effect (ME) ranging from 83.04% to 107.61%. The method was validated and the limit of detection (LOD) and limit of quantification (LOQ) were 1 and 5 μg/L, respectively, for both compounds and the precision with RSD ranged from 1% to 12%. This method proved to be quick, sensitive, rugged, and suitable for the analysis of illegal drugs in putrefied whole blood.
A method for simultaneous screening and determination of steviol glycosides in Chinese liquor and beverages by hydrophilic interaction ultra-high performance liquid chromatography-quadrupole/Orbitrap high resolution mass spectrometry (HILIC-UHPLC-Q/Orbitrap HRMS) was developed. In addition, the MS fragment path ways of steviol glycosides were characterized. The sample was diluted and filtrated before analysis, separated by a Waters Xbridge Amide column (150 mm×4.6 mm, 3.5 μm), and determined via UHPLC-Q/Orbitrap HRMS. The analytes were electronic using electro spray ion source in the negative mode, and the data were collected using full mass scan and data-dependent MS2 scan. Good linear relationships (10-1000 μg/L) were obtained. The limits of detection ranged from 0.3 to 20 μg/L. The mean recoveries varied from 81.9% to 106% at the spiked levels of 10-100 μg/kg, and the relative standard deviations ranged from 0.1% to 9.3% (n=3). Two characteristic fragment ions of steviol glycosides were identified by the analysis of fragment ion spectra of eight types of steviol glycosides standards. Non-targeted screening of unknown steviol glycosides in samples was carried out on the basis of the identified characteristic fragment ions. The proposed method is comprehensive, accurate, and sensitive for rapid screening and determination of sweeteners in food samples.
A method was developed for the determination of glufosinate-ammonium and its metabolites in litchi and banana by high performance liquid chromatography coupled with triple quadrupole mass spectrometry. The samples were ultrasound extracted by water, centrifuged to precipitate, and filtered through a 0.22 μm Millipore membrane. The sample extract was separated by an Extend-C18 column with 0.1% ammonia-methanol (9:1, v/v) as mobile phase with an isocratic elution, identified by electrospray ionization in negative and multiple reaction monitoring modes, and quantified with external standard method. Moreover, the pretreatment and mass spectrometry conditions were discussed. The method showed good linear relationship in the range of 1-1000 μg/L for glufosinate-ammonium and its metabolites. The average recoveries ranged from 82.9% to 98.6% with the relative standard deviations of 2.6%-6.3% when the litchi and banana samples were spiked at 50, 100, 1000 μg/kg. The limits of detection were 5-10 μg/kg. The method has rapid analysis speed as well as high reliability and sensitivity, which are suitable for the fast determination of glufosinate-ammonium and its metabolites in litchi and banana samples.
Macitentan (MAC) is a pulmonary arterial hypertension (PAH) drug marketed as a tablet and often has stability issues in the final dosage form. Quantitative determination of MAC and its associated impurities in tablet dosage form has not been previously reported. This study quantified impurities present in Macitentan tablets using a binary solvent-based gradient elution method using reversed phase-high performance liquid chromatography. The developed method was validated per International Conference on Harmonization (ICH) guidelines and the drug product was subjected to forced degradation studies to evaluate stability. The developed method efficiently separated the drug and impurities (48 min) without interference from solvents, excipients, or other impurities. The developed method met all guidelines in all characteristics with recoveries ranging from 85%-115%, linearity with r2 ≥ 0.9966, and substantial robustness. The stability-indicating nature of the method was evaluated using stressed conditions (hydrolysis:1 N HCl at 80℃/15 min; 1 N NaOH at 25℃/45 min; humidity stress (90% relative humidity) at 25℃ for 24 h, oxidation:at 6% (v/v) H2O2, 80℃/15 min, thermolysis:at 105℃/16 h and photolysis:UV light at 200 Wh/m2; Fluorescent light at 1.2 million luxh). Forced degradation experiments showed that the developed method was effective for impurity profiling. All stressed samples were assayed and mass balance was>96%. Forced degradation results indicated that MAC tablets were sensitive to hydrolysis (acid and alkali) and thermal conditions. The developed method is suitable for both assay and impurity determination, which is applicable to the pharmaceutical industry.
A method was established for the simultaneous determination of 12 preservatives and antioxidants in fruit and vegetable detergents by gas chromatography-mass spectrometry (GC-MS). First, ethanol was added to remove the water in the sample by rotary evaporation and was extracted with acetonitrile in saturated n-hexane. Finally, the residual surfactant in the sample solution was removed with a saturated sodium chloride solution. The purified sample solution was concentrated and metered volume by acetonitrile. The preservatives and antioxidants were separated on a HP-5MS UI capillary column (30 m×0.25 mm×0.25 μm), and detected in the selective ion monitoring (SIM) mode. The method had a good linearity in the range of 0.1-10 mg/L with correlation coefficients (r2)>0.999, and the limits of detection (LODs) and limits of quantification (LOQs) were in the ranges of 0.010-0.030 mg/kg and 0.030-0.090 mg/kg, respectively. The recoveries of the 12 preservatives and antioxidants at three spiked levels (0.2, 2.0 and 10 mg/kg) were 68.3%-115.3% with the relative standard deviations (RSDs) of 3.1%-11.3%. (n=7) The method is sensitive and accurate, and can be suitable for the determination of preservatives and antioxidants in fruit and vegetable detergents.
A new test method was established for the determination of purity and impurities of ethylene glycol (EG) by gas chromatography (GC) using a Rtx-624 column (30 m×0.32 mm×1.8 μm). The method determined not only the impurities in EG from the ethylene oxidation process, such as diethylene glycol, triethylene glycol and (1,3-dioxolan-2-yl)methanol, but also the impurities from the oxalate hydrogenation process, such as 1,2-butanediol, 1,4-butanediol, 1,2-hexanediol, and ethylene carbonate, etc. The method showed good repeatability and high detection sensitivity. The lowest LOD of the impurities reached to 0.0002% (mass fraction), and the recoveries of the impurities were in the range of 91.2%-105.4%. The proposed method can be applied in production control, product testing and market trade of ethylene glycol.
byDalian Institute of Chemical
Physics,CASNational Chromatographic R. and A.
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