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2015 Volume 33 Issue 4
2015, 33(4): 331-333
doi: 10.3724/SP.J.1123.2015.03011
Abstract:
2015, 33(4): 334-341
doi: 10.3724/SP.J.1123.2014.12041
Abstract:
Chirality is one of the intrinsic attributes of the nature. Chiral separation and analysis are of great importance in many research fields, such as life science, environmental science, biological engineering and pharmaceutical engineering. Currently, chiral capillary electrophoresis technique used for the enantioselective resolution of different kinds of racemates has become one of the most distinctive research and application fields. However, the adsorption of the analytes (or chiral selectors) on the inner wall of the capillary is a common problem in capillary electrophoresis chiral separation. Coating technology, namely modification of the inner wall of the capillary, is the simplest and most effective way to suppress disadvantageous adsorption, and to improve the separation efficiency and analysis repeatability. In this review, the recent applications of different coating procedures in chiral analysis are presented, and the future developments in this field are also prospected.
Chirality is one of the intrinsic attributes of the nature. Chiral separation and analysis are of great importance in many research fields, such as life science, environmental science, biological engineering and pharmaceutical engineering. Currently, chiral capillary electrophoresis technique used for the enantioselective resolution of different kinds of racemates has become one of the most distinctive research and application fields. However, the adsorption of the analytes (or chiral selectors) on the inner wall of the capillary is a common problem in capillary electrophoresis chiral separation. Coating technology, namely modification of the inner wall of the capillary, is the simplest and most effective way to suppress disadvantageous adsorption, and to improve the separation efficiency and analysis repeatability. In this review, the recent applications of different coating procedures in chiral analysis are presented, and the future developments in this field are also prospected.
2015, 33(4): 342-347
doi: 10.3724/SP.J.1123.2014.11029
Abstract:
A magnetic carbon nanotube hybrid material was prepared using a chemical co-precipitation method. The Fe3O4 nanoparticles were enclosed onto the surface of the acid multi-walled carbon nanotubes (AMWNTs), and they were identified as Fe3O4/AMWNTs composites. This hybrid materials displayed typical superparamagnetic behavior, good dispersibility, and good adsorption capacity for pyrethroid pesticides. A magnetic solid-phase microextraction (MSPE) procedure based on Fe3O4/AMWNTs composites, combined with gas chromatography, was developed for the quantification of six pyrethroid pesticides in water and honey samples. Several important parameters affecting the extraction efficiency for six pyrethroid pesticides were optimized in sequential order, including ionic strength, extraction time and desorption time. Under the optimized conditions, this method showed wide linearity ranging from 0.5 μg/L to 50 μg/L with correlation coefficients (R2) higher than 0.990. The limits of detection (LODs) ranged from 0.07 μg/L to 0.20 μg/L at a singal-to-noise ratio of 3. The relative standard deviations (RSDs) ranged from 3.8% to 8.1%. Satisfactory recoveries (>78.4%) were obtained for the simultaneous analysis of the six pyrethroid pesticide residues in river water, fishpond water and two honey samples. This method is sensitive and simple. It can meet the actual requirement for the analysis of trace analytes from environmental water and honey samples.
A magnetic carbon nanotube hybrid material was prepared using a chemical co-precipitation method. The Fe3O4 nanoparticles were enclosed onto the surface of the acid multi-walled carbon nanotubes (AMWNTs), and they were identified as Fe3O4/AMWNTs composites. This hybrid materials displayed typical superparamagnetic behavior, good dispersibility, and good adsorption capacity for pyrethroid pesticides. A magnetic solid-phase microextraction (MSPE) procedure based on Fe3O4/AMWNTs composites, combined with gas chromatography, was developed for the quantification of six pyrethroid pesticides in water and honey samples. Several important parameters affecting the extraction efficiency for six pyrethroid pesticides were optimized in sequential order, including ionic strength, extraction time and desorption time. Under the optimized conditions, this method showed wide linearity ranging from 0.5 μg/L to 50 μg/L with correlation coefficients (R2) higher than 0.990. The limits of detection (LODs) ranged from 0.07 μg/L to 0.20 μg/L at a singal-to-noise ratio of 3. The relative standard deviations (RSDs) ranged from 3.8% to 8.1%. Satisfactory recoveries (>78.4%) were obtained for the simultaneous analysis of the six pyrethroid pesticide residues in river water, fishpond water and two honey samples. This method is sensitive and simple. It can meet the actual requirement for the analysis of trace analytes from environmental water and honey samples.
2015, 33(4): 348-353
doi: 10.3724/SP.J.1123.2014.09028
Abstract:
A method for the determination of 23 antibiotics from 6 categories in water was developed by using solid-phase extraction and high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS). Water samples were enriched and cleaned-up by solid-phase extraction cartridges. The MS detection parameters of the analyzed antibiotics, the pH values of loading buffers and the volumes of the eluents were optimized by comparing the sample recoveries under different conditions. All antibiotics were separated by gradient elution with the mobile phases of 0.1% (v/v) formic acid and 1 g/L ammonium formate in water and acetonitrile-methanol (1:1, v/v) mixture. The eluate was then analyzed by HPLC-MS/MS in both positive and negative electrospray ionization conditions with multiple reaction monitoring (MRM) mode. The method detection limits (MDLs) were in the range of 0.1-2.9 ng/L and the recoveries of 23 antibiotics in water ranged from 47.3% to 132.6%. The developed method was applied to the analysis of 5 water samples from mariculture ponds located in Dongying City, Shandong Province. The results showed that the antibiotics could be detected in all water samples. The trimethoprim showed the highest detection rate, and the florfenicol had the highest mass concentration which reached 261.0 ng/L. The results showed that the developed method is efficient, sensitive and reliable, which is suitable for the detection of antibiotics in seawater samples.
A method for the determination of 23 antibiotics from 6 categories in water was developed by using solid-phase extraction and high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS). Water samples were enriched and cleaned-up by solid-phase extraction cartridges. The MS detection parameters of the analyzed antibiotics, the pH values of loading buffers and the volumes of the eluents were optimized by comparing the sample recoveries under different conditions. All antibiotics were separated by gradient elution with the mobile phases of 0.1% (v/v) formic acid and 1 g/L ammonium formate in water and acetonitrile-methanol (1:1, v/v) mixture. The eluate was then analyzed by HPLC-MS/MS in both positive and negative electrospray ionization conditions with multiple reaction monitoring (MRM) mode. The method detection limits (MDLs) were in the range of 0.1-2.9 ng/L and the recoveries of 23 antibiotics in water ranged from 47.3% to 132.6%. The developed method was applied to the analysis of 5 water samples from mariculture ponds located in Dongying City, Shandong Province. The results showed that the antibiotics could be detected in all water samples. The trimethoprim showed the highest detection rate, and the florfenicol had the highest mass concentration which reached 261.0 ng/L. The results showed that the developed method is efficient, sensitive and reliable, which is suitable for the detection of antibiotics in seawater samples.
2015, 33(4): 354-362
doi: 10.3724/SP.J.1123.2014.12005
Abstract:
A novel multiresidue analytical method has been developed and validated for the determination of five classes of veterinary drugs including 18 β-lactams, 15 quinolones, 21 sulfonamides, 3 sulfonamide potentiators and 6 antiparasitics in meat using dispersive solid-phase extraction (dispersive-SPE) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analytes were extracted with a vortex mixer by 0.1 mol/L Na2EDTA solution and acetonitrile containing 1% (v/v) acetic acid, and then the extracts were purified using dispersive-SPE with C18 sorbent. Electrospray ionization mass spectrometry was operated in positive mode using dynamic multiple reaction monitoring (DMRM) for the qualitative and quantitative analysis of the 63 analytes after the separation on a Poroshell EC-C18 column (100 mm×2.1 mm, 2.4 μm). The correlation coefficients of linear calibration curves were over 0.99 in the corresponding concentration ranges. The average recoveries of the 63 analytes ranged from 62.2% to 112.0%, and the relative standard deviations (RSDs) were 3.1%-16.3% in spiked meat (pork, beef and chicken muscle) at three levels. The limits of detection (LODs, S/N≥3) and the limits of quantification (LOQs, S/N≥10) were 0.1-3.0 μg/kg and 0.5-10.0 μg/kg, respectively. The method is simple, rapid, sensitive, reliable and suitable for the determination of residues in animal products.
A novel multiresidue analytical method has been developed and validated for the determination of five classes of veterinary drugs including 18 β-lactams, 15 quinolones, 21 sulfonamides, 3 sulfonamide potentiators and 6 antiparasitics in meat using dispersive solid-phase extraction (dispersive-SPE) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analytes were extracted with a vortex mixer by 0.1 mol/L Na2EDTA solution and acetonitrile containing 1% (v/v) acetic acid, and then the extracts were purified using dispersive-SPE with C18 sorbent. Electrospray ionization mass spectrometry was operated in positive mode using dynamic multiple reaction monitoring (DMRM) for the qualitative and quantitative analysis of the 63 analytes after the separation on a Poroshell EC-C18 column (100 mm×2.1 mm, 2.4 μm). The correlation coefficients of linear calibration curves were over 0.99 in the corresponding concentration ranges. The average recoveries of the 63 analytes ranged from 62.2% to 112.0%, and the relative standard deviations (RSDs) were 3.1%-16.3% in spiked meat (pork, beef and chicken muscle) at three levels. The limits of detection (LODs, S/N≥3) and the limits of quantification (LOQs, S/N≥10) were 0.1-3.0 μg/kg and 0.5-10.0 μg/kg, respectively. The method is simple, rapid, sensitive, reliable and suitable for the determination of residues in animal products.
2015, 33(4): 363-370
doi: 10.3724/SP.J.1123.2014.12009
Abstract:
A method for the simultaneous determination of 22 acidic dyes (acid yellow 23, acid red 18, acid blue 7, etc) in edible packagings was developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The samples were extracted with acetonitrile-methanol (5:5, v/v), and then cleaned up with Strata-X-AW solid-phase extractor. The analytes were separated on a Zorbax Eclipse Plus C18 column (100 mm×3.0 mm, 1.8 μm) by gradient elution with acetonitrile-10 mmol/L ammonium acetate as the mobile phases. The 22 acidic dyes were determined by electrospray negative ion source (ESI-), and multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions, and the quantitative analysis was carried out by matrix-matched external standard method. The results showed that the calibration curves had good linearity for the 22 acidic dyes, and the correlation coefficients (r2) were larger than 0.991. The limits of quantitation (LOQs, S/N≥10) were in the range of 0.1-2.0 mg/kg in three different matrices (plant capsule, gelatine capsule, oblatum). The average recoveries were in the range of 78.4%-109.5% for the 22 acidic dyes with the relative standard deviations (RSDs) from 4.6% to 14.5% at three spiked levels (1×LOQ, 2×LOQ and 10×LOQ). This method is suitable for the determination of acidic dyes in edible packagings with the characteristics of high accuracy and precision.
A method for the simultaneous determination of 22 acidic dyes (acid yellow 23, acid red 18, acid blue 7, etc) in edible packagings was developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The samples were extracted with acetonitrile-methanol (5:5, v/v), and then cleaned up with Strata-X-AW solid-phase extractor. The analytes were separated on a Zorbax Eclipse Plus C18 column (100 mm×3.0 mm, 1.8 μm) by gradient elution with acetonitrile-10 mmol/L ammonium acetate as the mobile phases. The 22 acidic dyes were determined by electrospray negative ion source (ESI-), and multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions, and the quantitative analysis was carried out by matrix-matched external standard method. The results showed that the calibration curves had good linearity for the 22 acidic dyes, and the correlation coefficients (r2) were larger than 0.991. The limits of quantitation (LOQs, S/N≥10) were in the range of 0.1-2.0 mg/kg in three different matrices (plant capsule, gelatine capsule, oblatum). The average recoveries were in the range of 78.4%-109.5% for the 22 acidic dyes with the relative standard deviations (RSDs) from 4.6% to 14.5% at three spiked levels (1×LOQ, 2×LOQ and 10×LOQ). This method is suitable for the determination of acidic dyes in edible packagings with the characteristics of high accuracy and precision.
2015, 33(4): 371-376
doi: 10.3724/SP.J.1123.2014.11020
Abstract:
A method for rapid screening and quantification of 11 antidiabetics (nateglinide, pioglitazone hydrochloride, gliquidone, gliclazide, glipizide, glibenclamide, metformin hydrochloride, repaglinide, phenformin hydrochloride, rosiglitazone hydrochloride, glimepiride) illegally added in health care products by ultra performance liquid chromatography (UPLC)-quadrupole/electrostatic field orbitrap mass spectrometry was established. The samples were extracted with methanol, and separated on an Agilent Poroshell 120 SB-C18 column (100 mm×4.6 mm, 2.7 μm) with acetonitrile-10 mmol/L ammonium acetate solution as mobile phases by gradient elution. The positive mode was used in the MS detection. The resolution of the precursor mass was 70000, while the resolution of the product mass was 17500. The results indicated that the linearity of all the 11 antidiabetics ranged from 0.005 mg/L to 0.5 mg/L with the correlation coefficients greater than 0.99. The limits of detection were confirmed by spiked samples, and were between 2.7 and 5.1 μg/kg for the 11 antidiabetics. The recoveries were in the range of 87.3% to 98.3%, with the relative standard deviations in the range of 2.18%-5.21%. This method is accurate, simple and rapid, and can be used in rapid screening and quantitative analysis of the 11 illegally added antidiabetics in health care products.
A method for rapid screening and quantification of 11 antidiabetics (nateglinide, pioglitazone hydrochloride, gliquidone, gliclazide, glipizide, glibenclamide, metformin hydrochloride, repaglinide, phenformin hydrochloride, rosiglitazone hydrochloride, glimepiride) illegally added in health care products by ultra performance liquid chromatography (UPLC)-quadrupole/electrostatic field orbitrap mass spectrometry was established. The samples were extracted with methanol, and separated on an Agilent Poroshell 120 SB-C18 column (100 mm×4.6 mm, 2.7 μm) with acetonitrile-10 mmol/L ammonium acetate solution as mobile phases by gradient elution. The positive mode was used in the MS detection. The resolution of the precursor mass was 70000, while the resolution of the product mass was 17500. The results indicated that the linearity of all the 11 antidiabetics ranged from 0.005 mg/L to 0.5 mg/L with the correlation coefficients greater than 0.99. The limits of detection were confirmed by spiked samples, and were between 2.7 and 5.1 μg/kg for the 11 antidiabetics. The recoveries were in the range of 87.3% to 98.3%, with the relative standard deviations in the range of 2.18%-5.21%. This method is accurate, simple and rapid, and can be used in rapid screening and quantitative analysis of the 11 illegally added antidiabetics in health care products.
2015, 33(4): 377-382
doi: 10.3724/SP.J.1123.2014.12010
Abstract:
A method of ultra-performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (UPLC-LTQ/Orbitrap MS) was used to determine 24 free carcinogenic aromatic amines in textiles. The main factors influencing the method, including the extraction solvent, the extraction temperature and the extraction time, were optimized. Under the optimized experimental conditions, the analytes were extracted by dichloromethane for 10 min and loaded into a ZORBAX SB-C18 column (150 mm×2.1 mm, 5 μm) with a gradient elution of methanol and 0.1% aqueous formic acid solution, and finally detected by LTQ/Orbitrap MS. The screening and quantitative analysis were carried out by the accurate mass of quasi-molecular ion and the peak in extracted chromatogram with accurate mass respectively. The correlation coefficients (R2) were higher than 0.99. The recoveries were 87.8%-105.6% with the RSDs were 1.6%-3.4%. The limits of detection were 0.5-1 μg/kg, and the limits of quantification were 1.5-3 μg/kg. The proposed method was applied to 14 textile samples containing spandex. 4,4'-Diaminodiphenylmethane was determined in five samples and the contents were 0.21-25.6 mg/kg. The results indicate that the developed method is a simple, efficient, precise and reliable technique for the determination of free carcinogenic aromatic amines in textiles.
A method of ultra-performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (UPLC-LTQ/Orbitrap MS) was used to determine 24 free carcinogenic aromatic amines in textiles. The main factors influencing the method, including the extraction solvent, the extraction temperature and the extraction time, were optimized. Under the optimized experimental conditions, the analytes were extracted by dichloromethane for 10 min and loaded into a ZORBAX SB-C18 column (150 mm×2.1 mm, 5 μm) with a gradient elution of methanol and 0.1% aqueous formic acid solution, and finally detected by LTQ/Orbitrap MS. The screening and quantitative analysis were carried out by the accurate mass of quasi-molecular ion and the peak in extracted chromatogram with accurate mass respectively. The correlation coefficients (R2) were higher than 0.99. The recoveries were 87.8%-105.6% with the RSDs were 1.6%-3.4%. The limits of detection were 0.5-1 μg/kg, and the limits of quantification were 1.5-3 μg/kg. The proposed method was applied to 14 textile samples containing spandex. 4,4'-Diaminodiphenylmethane was determined in five samples and the contents were 0.21-25.6 mg/kg. The results indicate that the developed method is a simple, efficient, precise and reliable technique for the determination of free carcinogenic aromatic amines in textiles.
2015, 33(4): 383-388
doi: 10.3724/SP.J.1123.2014.12007
Abstract:
The difference of serum metabolome between hepatitis B virus (HBV) infected patients and healthy controls was explored for the potential metabolite biomarkers of HBV disease using serum metabolomics approach. Totally 30 HBV infected patients and 35 healthy controls were enrolled. Gas chromatography-time-of-flight mass spectrometry (GC-TOFMS), pattern recognition by principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were applied in each group. Several metabolites which were different between the two groups based on variable importance in projection (VIP) value, non-parametric test and screening in databases were identified. Ten variables that were significantly different were considered as the potential biomarkers, among which five variables (citric acid, aconitic acid, glutamine, N,N-dimethylglycine and malonic acid) showed good correlation with HBV patients. The area under the receiver operating characteristic curve was 0.975, with good specificity and sensitivity. A panel of metabolite markers composed of citric acid, aconitic acid, glutamine, N,N-dimethylglycine and malonic acid from GC-TOFMS were selected to discriminate HBV subjects from their healthy counterparts. These biochemical changes provide a novel molecular diagnostic approach which could be helpful to further understand the pathogenesis and identify the therapeutic target of HBV disease.
The difference of serum metabolome between hepatitis B virus (HBV) infected patients and healthy controls was explored for the potential metabolite biomarkers of HBV disease using serum metabolomics approach. Totally 30 HBV infected patients and 35 healthy controls were enrolled. Gas chromatography-time-of-flight mass spectrometry (GC-TOFMS), pattern recognition by principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were applied in each group. Several metabolites which were different between the two groups based on variable importance in projection (VIP) value, non-parametric test and screening in databases were identified. Ten variables that were significantly different were considered as the potential biomarkers, among which five variables (citric acid, aconitic acid, glutamine, N,N-dimethylglycine and malonic acid) showed good correlation with HBV patients. The area under the receiver operating characteristic curve was 0.975, with good specificity and sensitivity. A panel of metabolite markers composed of citric acid, aconitic acid, glutamine, N,N-dimethylglycine and malonic acid from GC-TOFMS were selected to discriminate HBV subjects from their healthy counterparts. These biochemical changes provide a novel molecular diagnostic approach which could be helpful to further understand the pathogenesis and identify the therapeutic target of HBV disease.
2015, 33(4): 389-396
doi: 10.3724/SP.J.1123.2014.12026
Abstract:
The performances of gas chromatography-tandem mass spectrometry (GC-MS/MS) and gas chromatography quadrupole time of flight mass spectrometry (GC-QTOF/MS) for the determination of 208 pesticide residues in fruit and vegetable samples, including apple, orange, tomato and cucumber, were compared comprehensively. Based on the differences of the two instruments, their respective characteristics and scopes of application in the detection of the pesticide residues were presented, which provided the reference for the analysis of pesticide residues. The performance parameters of the two instruments, such as overall recoveries, precisions, limits of detection, linear ranges, identification points and matrix effects, were evaluated according to a designed experiment. At three spiked levels (5.0, 10.0 and 20.0 μg/kg), the average recoveries for the majority of pesticides (93.0%) ranged from 70% to 120% in the four matrices with relative standard deviations below 20%. The limits of detection for most of the pesticides by GC-MS/MS and GC-Q-TOF/MS were less than 5.0 μg/kg. Compared with GC-QTOF/MS, GC-MS/MS showed relatively lower limits of detection and wider linear ranges, and its performance was more satisfactory in accurate quantitative analysis due to its superior sensitivity. On the other hand, GC-QTOF/MS provided accurate mass measurement, which was proved to be an efficient analytical tool on the rapid screening and confirmation of a large number of pesticides and non-target compounds.
The performances of gas chromatography-tandem mass spectrometry (GC-MS/MS) and gas chromatography quadrupole time of flight mass spectrometry (GC-QTOF/MS) for the determination of 208 pesticide residues in fruit and vegetable samples, including apple, orange, tomato and cucumber, were compared comprehensively. Based on the differences of the two instruments, their respective characteristics and scopes of application in the detection of the pesticide residues were presented, which provided the reference for the analysis of pesticide residues. The performance parameters of the two instruments, such as overall recoveries, precisions, limits of detection, linear ranges, identification points and matrix effects, were evaluated according to a designed experiment. At three spiked levels (5.0, 10.0 and 20.0 μg/kg), the average recoveries for the majority of pesticides (93.0%) ranged from 70% to 120% in the four matrices with relative standard deviations below 20%. The limits of detection for most of the pesticides by GC-MS/MS and GC-Q-TOF/MS were less than 5.0 μg/kg. Compared with GC-QTOF/MS, GC-MS/MS showed relatively lower limits of detection and wider linear ranges, and its performance was more satisfactory in accurate quantitative analysis due to its superior sensitivity. On the other hand, GC-QTOF/MS provided accurate mass measurement, which was proved to be an efficient analytical tool on the rapid screening and confirmation of a large number of pesticides and non-target compounds.
2015, 33(4): 397-402
doi: 10.3724/SP.J.1123.2014.12004
Abstract:
A fast analytical method for five common fatty acids in six edible vegetable oils was developed by ultra-performance convergence chromatography-mass spectrometry (UPC2-MS). The five fatty acids are palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid. Their contents in the corn oil, sunflower oil, soybean oil, tea oil, rapeseed oil and peanut oil were compared. The chromatographic separation was performed on an ACQUITY UPC2 BEH 2-EP column (100 mm×2.1 mm, 1.7 μm) using the mobile phases of carbon dioxide and methanol/acetonitrile (1:1, v/v) with gradient elution. The separated compounds were detected by negative electrospray ionization ESI--MS. The results showed that the reasonable linearities were achieved for all the analytes over the range of 0.5-100 mg/L with the correlation coefficients (R2) of 0.9985-0.9998. The limits of quantification(S/N≥10)of the five fatty acids were 0.15-0.50 mg/L. The recoveries of the five fatty acids at three spiked levels were in the range of 89.61%-108.50% with relative standard deviations of 0.69%-3.01%. The developed method showed high performance, good resolution and fast analysis for the underivatized fatty acids. It has been successfully used to detect the five fatty acids from corn oil, sunflower oil, soybean oil, tea oil, rapeseed oil and peanut oil.
A fast analytical method for five common fatty acids in six edible vegetable oils was developed by ultra-performance convergence chromatography-mass spectrometry (UPC2-MS). The five fatty acids are palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid. Their contents in the corn oil, sunflower oil, soybean oil, tea oil, rapeseed oil and peanut oil were compared. The chromatographic separation was performed on an ACQUITY UPC2 BEH 2-EP column (100 mm×2.1 mm, 1.7 μm) using the mobile phases of carbon dioxide and methanol/acetonitrile (1:1, v/v) with gradient elution. The separated compounds were detected by negative electrospray ionization ESI--MS. The results showed that the reasonable linearities were achieved for all the analytes over the range of 0.5-100 mg/L with the correlation coefficients (R2) of 0.9985-0.9998. The limits of quantification(S/N≥10)of the five fatty acids were 0.15-0.50 mg/L. The recoveries of the five fatty acids at three spiked levels were in the range of 89.61%-108.50% with relative standard deviations of 0.69%-3.01%. The developed method showed high performance, good resolution and fast analysis for the underivatized fatty acids. It has been successfully used to detect the five fatty acids from corn oil, sunflower oil, soybean oil, tea oil, rapeseed oil and peanut oil.
2015, 33(4): 403-407
doi: 10.3724/SP.J.1123.2014.12045
Abstract:
The amphiphilic copolymer poly (styrene-co-methacrylic acid) (P(St-co-MAA)) with molar ratios of 6:4 and 7:3 self-assembled to form micelles. The polymeric micelles were used as pseudostationary phase (PSP) in micellar electrokinetic chromatography (MEKC). Their physicochemical properties and MEKC performance were investigated as well in the present work. The critical micelle concentration (CMC), polarity, surface charge density and hydrodynamic diameter were used to characterize the solution physicochemical properties, while the methylene group selectivity was evaluated with n-alkylphenone homologous series. The time window and linear solvation energy relationship (LSER) analysis were used to characterize the MEKC retention behavior and the selectivity. All of these were compared with poly (methyl methacrylate-co-methacrylic acid) (P(MMA-co-MAA)) with the molar ratio of 7:3 and sodium dodecyl sulfate (SDS) micellar systems. The results showed that P(St-co-MAA) system had the minimum CMC, the widest time window and the best methylene group selectivity. LSER analysis results showed that the hydrophobic effect was the most important interaction between solutes and PSPs, and the hydrogen-bonding acidity was the second significant factor on selectivity and MEKC retention behavior. P(St-co-MAA) system, especially with the molar ratio of 7:3, had the highest effective parameter in LSER and showed a high separation selectivity of PSP.
The amphiphilic copolymer poly (styrene-co-methacrylic acid) (P(St-co-MAA)) with molar ratios of 6:4 and 7:3 self-assembled to form micelles. The polymeric micelles were used as pseudostationary phase (PSP) in micellar electrokinetic chromatography (MEKC). Their physicochemical properties and MEKC performance were investigated as well in the present work. The critical micelle concentration (CMC), polarity, surface charge density and hydrodynamic diameter were used to characterize the solution physicochemical properties, while the methylene group selectivity was evaluated with n-alkylphenone homologous series. The time window and linear solvation energy relationship (LSER) analysis were used to characterize the MEKC retention behavior and the selectivity. All of these were compared with poly (methyl methacrylate-co-methacrylic acid) (P(MMA-co-MAA)) with the molar ratio of 7:3 and sodium dodecyl sulfate (SDS) micellar systems. The results showed that P(St-co-MAA) system had the minimum CMC, the widest time window and the best methylene group selectivity. LSER analysis results showed that the hydrophobic effect was the most important interaction between solutes and PSPs, and the hydrogen-bonding acidity was the second significant factor on selectivity and MEKC retention behavior. P(St-co-MAA) system, especially with the molar ratio of 7:3, had the highest effective parameter in LSER and showed a high separation selectivity of PSP.
2015, 33(4): 408-412
doi: 10.3724/SP.J.1123.2014.12016
Abstract:
A matrix solid-phase dispersion-ultra performance liquid chromatography-tandem mass spectrometry (MSPD-UPLC-MS/MS) method was established for the simultaneous determination of carbendiazin, omethoate, carbofuran, aldicarb, chlorpyrifos, methamidophos, phorate, parathion and parathion-methyl residues in vegetables. The samples were extracted by acetonitrile and separated with salting out method. And then the supernatants were purified by matrix solid-phase dispersion for the UPLC-MS/MS analysis. The separation was performed on a Waters Acquity UPLC system with a BEH C18 column with the gradient elution of acetonitrile and water containing 0.1%(v/v) acetic acid. The nine pesticides were determined in the modes of electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM). The analytes were quantified by matrix matched standard solution curves. The limits of detection (S/N≥3) were 0.8-4.0 μg/kg. The average recoveries were 72.8%-117.4%. The detection rates were 42.0% for chlorpyrifos, 14.0% for carbendiazin and 1.5% for dimethoate, and the excessive rate of chlorpyrifos was 8.0% in the determination of 50 real samples; the other pesticides were not detected. The method is simple, accurate and highly reproducible. This method is suitable for the quality control of pesticide residues in risk monitoring of the safety of the foods.
A matrix solid-phase dispersion-ultra performance liquid chromatography-tandem mass spectrometry (MSPD-UPLC-MS/MS) method was established for the simultaneous determination of carbendiazin, omethoate, carbofuran, aldicarb, chlorpyrifos, methamidophos, phorate, parathion and parathion-methyl residues in vegetables. The samples were extracted by acetonitrile and separated with salting out method. And then the supernatants were purified by matrix solid-phase dispersion for the UPLC-MS/MS analysis. The separation was performed on a Waters Acquity UPLC system with a BEH C18 column with the gradient elution of acetonitrile and water containing 0.1%(v/v) acetic acid. The nine pesticides were determined in the modes of electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM). The analytes were quantified by matrix matched standard solution curves. The limits of detection (S/N≥3) were 0.8-4.0 μg/kg. The average recoveries were 72.8%-117.4%. The detection rates were 42.0% for chlorpyrifos, 14.0% for carbendiazin and 1.5% for dimethoate, and the excessive rate of chlorpyrifos was 8.0% in the determination of 50 real samples; the other pesticides were not detected. The method is simple, accurate and highly reproducible. This method is suitable for the quality control of pesticide residues in risk monitoring of the safety of the foods.
2015, 33(4): 413-418
doi: 10.3724/SP.J.1123.2014.12035
Abstract:
The spectrum-effect relationship on anti-hepatic fibrosis effect of Radix Hedysari was explored based on high performance liquid chromatographic technique. Hepatic fibrosis was induced in mice by administering a subcutaneous injection of carbon tetrachloride-peanut oil (4:6, v/v) continuously for 35 d at a interval of 5 d (0.1 mL/10 g). And at the same time of modeling, the different extracts of Radix Hedysari were administered orally once daily at a dose of 10 g/kg. The ethanol extract of Radix Hedysari was specified to be most effective on anti-hepatic fibrosis by determining the levels of alanine aminotransferase, aspartate transaminase, total-protein, albumin, albumin/globulin (ALT, AST, TP, ALB, and A/G) in serum and relative liver weight. Subsequently, the grey relational degree analysis and partial least squares analysis were employed to reveal the correlation between chromatographic fingerprint of ethanol extract of Radix Hedysari from 10 different geographical origins and its anti-hepatic fibrosis efficacy. The results suggest that most chemical constituents of Radix Hedysari have a high correlation with the effect of anti-hepatic fibrosis (>0.8), which indicates that the effect is related to the various components in Radix Hedysari. Adenosine, calycosin and ononin in ethanol extract of Radix Hedysari have been identified separately among which adenosine and calycosin made the great contribution to the anti-hepatic fibrosis effect.
The spectrum-effect relationship on anti-hepatic fibrosis effect of Radix Hedysari was explored based on high performance liquid chromatographic technique. Hepatic fibrosis was induced in mice by administering a subcutaneous injection of carbon tetrachloride-peanut oil (4:6, v/v) continuously for 35 d at a interval of 5 d (0.1 mL/10 g). And at the same time of modeling, the different extracts of Radix Hedysari were administered orally once daily at a dose of 10 g/kg. The ethanol extract of Radix Hedysari was specified to be most effective on anti-hepatic fibrosis by determining the levels of alanine aminotransferase, aspartate transaminase, total-protein, albumin, albumin/globulin (ALT, AST, TP, ALB, and A/G) in serum and relative liver weight. Subsequently, the grey relational degree analysis and partial least squares analysis were employed to reveal the correlation between chromatographic fingerprint of ethanol extract of Radix Hedysari from 10 different geographical origins and its anti-hepatic fibrosis efficacy. The results suggest that most chemical constituents of Radix Hedysari have a high correlation with the effect of anti-hepatic fibrosis (>0.8), which indicates that the effect is related to the various components in Radix Hedysari. Adenosine, calycosin and ononin in ethanol extract of Radix Hedysari have been identified separately among which adenosine and calycosin made the great contribution to the anti-hepatic fibrosis effect.
2015, 33(4): 419-422
doi: 10.3724/SP.J.1123.2014.11014
Abstract:
A method was developed for the determination of ethylene glycol bis(2-aminoethyl) ether-N,N,N,N-tetraacetic acid (EGTA) by high performance liquid chromatography (HPLC). The content of EGTA can be determined by that of EGTA-Cu through the complexation between EGTA and Cu2+. The chromatographic separation was performed on an Ultimate-AQ C18 analytical column (250 mm×4.6 mm, 5 μm) using the mobile phase of acetonitrile-ion-pairing reagents (with 0.3% tetrabutyl ammonium hydroxide in mass fraction adjusted to pH 6.50 using acetate)-buffered saline (35 mmol/L sodium acetate of pH 6.50) (20:20:60, v/v/v). The chromatographic conditions were as follows: flow rate, 1.50 mL/min; detection wavelength, 245 nm; injection volume, 100 μL; column temperature, 40 ℃. Under the conditions, good linear relationships between the mass concentration and the peak area of EGTA were observed in the range of 0.10-15.00 mg/L (R=0.9998). The limit of detection (LOD, S/N=3) and limit of quantitation (LOQ, S/N=10) were determined as 0.05 mg/L and 0.17 mg/L, respectively. The average recoveries were 98.34%-99.03% with the RSDs of 1.08%-3.33%(n=9). The results showed that the developed method is sensitive, accurate, reproducible and suitable for the analysis of EGTA in medicine.
A method was developed for the determination of ethylene glycol bis(2-aminoethyl) ether-N,N,N,N-tetraacetic acid (EGTA) by high performance liquid chromatography (HPLC). The content of EGTA can be determined by that of EGTA-Cu through the complexation between EGTA and Cu2+. The chromatographic separation was performed on an Ultimate-AQ C18 analytical column (250 mm×4.6 mm, 5 μm) using the mobile phase of acetonitrile-ion-pairing reagents (with 0.3% tetrabutyl ammonium hydroxide in mass fraction adjusted to pH 6.50 using acetate)-buffered saline (35 mmol/L sodium acetate of pH 6.50) (20:20:60, v/v/v). The chromatographic conditions were as follows: flow rate, 1.50 mL/min; detection wavelength, 245 nm; injection volume, 100 μL; column temperature, 40 ℃. Under the conditions, good linear relationships between the mass concentration and the peak area of EGTA were observed in the range of 0.10-15.00 mg/L (R=0.9998). The limit of detection (LOD, S/N=3) and limit of quantitation (LOQ, S/N=10) were determined as 0.05 mg/L and 0.17 mg/L, respectively. The average recoveries were 98.34%-99.03% with the RSDs of 1.08%-3.33%(n=9). The results showed that the developed method is sensitive, accurate, reproducible and suitable for the analysis of EGTA in medicine.
2015, 33(4): 423-427
doi: 10.3724/SP.J.1123.2014.12015
Abstract:
An HPLC method was developed for the simultaneous determination of 11 constituents, 5-hydroxymethyl furfural (5-HMF), vicenin-2, hesperidin, hesperetin, isosinensetin, sinensetin, tetramethyl-O-isoscutellarein (TEOS), nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone (HEPTA), tangeretin, 5-demethylnobiletin in Citrus reticulate 'Chachi'. The separation was conducted on a Hanbon Benatach C18 column (250 mm×4.6 mm, 5 μm) with acetonitrile and 0.2% formic acid as mobile phases with gradient elution. The flow rate was 1.0 mL/min. The detection wavelength was 280 nm. The column temperature was 25 ℃. The results showed that the correlation coefficients (r) between concentration and chromatographic peak area of the 11 constituents were over 0.998 in the selected linear ranges. The limits of detection (LODs, S/N=3) and limits of quantification (LOQs, S/N=10) of the 11 constituents were in the range of 0.0125-1.25 mg/L and 0.0502-4.99 mg/L, respectively. The average recoveries (n=3) of the 11 constituents were in the range of 96.4%-102.4% and the RSDs were 0.25%-4.01%. The developed method has been successfully applied for the analysis of eight samples from different cultivation regions in Guangdong Province. This method is simple, accurate and effective for the simultaneous determination of the 11 components, and suitable for the quality control of Citrus reticulate 'Chachi'.
An HPLC method was developed for the simultaneous determination of 11 constituents, 5-hydroxymethyl furfural (5-HMF), vicenin-2, hesperidin, hesperetin, isosinensetin, sinensetin, tetramethyl-O-isoscutellarein (TEOS), nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone (HEPTA), tangeretin, 5-demethylnobiletin in Citrus reticulate 'Chachi'. The separation was conducted on a Hanbon Benatach C18 column (250 mm×4.6 mm, 5 μm) with acetonitrile and 0.2% formic acid as mobile phases with gradient elution. The flow rate was 1.0 mL/min. The detection wavelength was 280 nm. The column temperature was 25 ℃. The results showed that the correlation coefficients (r) between concentration and chromatographic peak area of the 11 constituents were over 0.998 in the selected linear ranges. The limits of detection (LODs, S/N=3) and limits of quantification (LOQs, S/N=10) of the 11 constituents were in the range of 0.0125-1.25 mg/L and 0.0502-4.99 mg/L, respectively. The average recoveries (n=3) of the 11 constituents were in the range of 96.4%-102.4% and the RSDs were 0.25%-4.01%. The developed method has been successfully applied for the analysis of eight samples from different cultivation regions in Guangdong Province. This method is simple, accurate and effective for the simultaneous determination of the 11 components, and suitable for the quality control of Citrus reticulate 'Chachi'.
2015, 33(4): 428-433
doi: 10.3724/SP.J.1123.2014.12018
Abstract:
The separations of the immunosuppressive reagents, capsaicinoids, vitamin E, curcumins on cyclofructan based stationary phases containing polystyrene supported native cyclofructan (MCI Gel CRS100), silica supported native cyclofructan (Frulic N), silica supported isopropyl carbamate cyclofructan 6 (Larihc P), silica supported R-naphthylethyl carbamate cyclofructan 6 (Larihc RN) in normal phase HPLC mode were studied. From the investigation it showed that the column MCI Gel CRS100 was more suitable for the separation in normal phase than in hydrophilic interaction liquid chromatography. Derivatized cyclofructan stationary phases, Larihc P and Larihc RN, showed better selectivities in comparison with the native cyclofructan stationary phases. Trifluoroacetic acid had less influence on resolution on cyclofructan based stationary phases in normal phase mode.
The separations of the immunosuppressive reagents, capsaicinoids, vitamin E, curcumins on cyclofructan based stationary phases containing polystyrene supported native cyclofructan (MCI Gel CRS100), silica supported native cyclofructan (Frulic N), silica supported isopropyl carbamate cyclofructan 6 (Larihc P), silica supported R-naphthylethyl carbamate cyclofructan 6 (Larihc RN) in normal phase HPLC mode were studied. From the investigation it showed that the column MCI Gel CRS100 was more suitable for the separation in normal phase than in hydrophilic interaction liquid chromatography. Derivatized cyclofructan stationary phases, Larihc P and Larihc RN, showed better selectivities in comparison with the native cyclofructan stationary phases. Trifluoroacetic acid had less influence on resolution on cyclofructan based stationary phases in normal phase mode.
2015, 33(4): 434-440
doi: 10.3724/SP.J.1123.2014.12022
Abstract:
An analytical method was developed for the determination of 11 sulfonamide compounds in aquaculture water and sediments by high performance liquid chromatography (HPLC) coupled with post-column derivatization. The filtered water sample was purified and concentrated with HLB cartridge, while the sediment sample was extracted with a mixture of methanol and EDTA-Mcllvaine buffer (1:1, v/v), and then purified and enriched through HLB solid-phase extraction. The sulfonamides were separated on a C18 column by HPLC and on-line derivatized with a fluorescamine and detected with a fluorescence detector. The parameters of post-column derivatization system were optimized, and the fluorescamine solution concentration, velocity of reagent solution and reaction temperature were 0.2 g/L, 0.15 mL/min and 50 ℃, respectively. The calibration curves of the method showed good linearity in the range of 0.01-1.0 mg/L, with the correlation coefficients (r2) all above 0.99995. The recoveries were 79.3%-100.7% and 74.6%-95.3% with RSD values of 2.2%-11.0% and 2.6%-10.3% for the 11 sulfonamides in aquaculture water and sediments, respectively. The respective limits of detection (LODs, S/N=3) were 0.9-5.5 ng/L and 0.3-1.3 μg/kg and the limits of quantification (LOQs, S/N=10) were 3.0-18.1 ng/L and 1.0-4.4 μg/kg. The method can be applied to the determination of sulfonamides in the aquaculture environment, and it has a good practicability.
An analytical method was developed for the determination of 11 sulfonamide compounds in aquaculture water and sediments by high performance liquid chromatography (HPLC) coupled with post-column derivatization. The filtered water sample was purified and concentrated with HLB cartridge, while the sediment sample was extracted with a mixture of methanol and EDTA-Mcllvaine buffer (1:1, v/v), and then purified and enriched through HLB solid-phase extraction. The sulfonamides were separated on a C18 column by HPLC and on-line derivatized with a fluorescamine and detected with a fluorescence detector. The parameters of post-column derivatization system were optimized, and the fluorescamine solution concentration, velocity of reagent solution and reaction temperature were 0.2 g/L, 0.15 mL/min and 50 ℃, respectively. The calibration curves of the method showed good linearity in the range of 0.01-1.0 mg/L, with the correlation coefficients (r2) all above 0.99995. The recoveries were 79.3%-100.7% and 74.6%-95.3% with RSD values of 2.2%-11.0% and 2.6%-10.3% for the 11 sulfonamides in aquaculture water and sediments, respectively. The respective limits of detection (LODs, S/N=3) were 0.9-5.5 ng/L and 0.3-1.3 μg/kg and the limits of quantification (LOQs, S/N=10) were 3.0-18.1 ng/L and 1.0-4.4 μg/kg. The method can be applied to the determination of sulfonamides in the aquaculture environment, and it has a good practicability.
2015, 33(4): 441-445
doi: 10.3724/SP.J.1123.2014.12023
Abstract:
A method for the detection of trace 1,4-dioxane in drinking water using headspace solid-phase microextraction (HS/SPME) with gas chromatography/flame ionization detector (FID) was presented. Both the extraction conditions (SPME fiber, extraction temperature, extraction time, pH and sample volume, et al) and the gas chromatographic conditions were optimized. The results showed that the best response was obtained with 85 μm Carboxen-PDMS above 3 mL water in a 20-mL screw capped vial containing 3 mL sodium hydroxide solution (600 g/L). The best chromatographic separation was obtained on a PTA-5 capillary column (30 m×0.53 mm×3.0 μm) which was modified with alkali-bonding and of large pores and thick film. The linear range for 1,4-dioxane was 0.50-50.0 μg/L with the correlation coefficient (r) of 0.9995. The limit of detection (S/N>3) was 0.14 μg/L. The recoveries for the actual water samples at low, medium and high spiked levels were 95.5%-107%, with the relative standard deviations of 1.1%-5.3% (n=6). The developed method is simple, accurate, reproducible and highly sensitive. It is suitable for the routine monitoring of trace amount of 1,4-dioxane in the drinking water.
A method for the detection of trace 1,4-dioxane in drinking water using headspace solid-phase microextraction (HS/SPME) with gas chromatography/flame ionization detector (FID) was presented. Both the extraction conditions (SPME fiber, extraction temperature, extraction time, pH and sample volume, et al) and the gas chromatographic conditions were optimized. The results showed that the best response was obtained with 85 μm Carboxen-PDMS above 3 mL water in a 20-mL screw capped vial containing 3 mL sodium hydroxide solution (600 g/L). The best chromatographic separation was obtained on a PTA-5 capillary column (30 m×0.53 mm×3.0 μm) which was modified with alkali-bonding and of large pores and thick film. The linear range for 1,4-dioxane was 0.50-50.0 μg/L with the correlation coefficient (r) of 0.9995. The limit of detection (S/N>3) was 0.14 μg/L. The recoveries for the actual water samples at low, medium and high spiked levels were 95.5%-107%, with the relative standard deviations of 1.1%-5.3% (n=6). The developed method is simple, accurate, reproducible and highly sensitive. It is suitable for the routine monitoring of trace amount of 1,4-dioxane in the drinking water.
