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2013 Volume 31 Issue 11
2013, 31(11): 1035-1039
doi: 10.3724/SP.J.1123.2013.06021
Abstract:
A new kind of silica-bonded reserved stationary phase with s-triazine and amide polar groups embedded for HPLC was obtained by step-wise reactions of silica gel with s-triazine, γ-aminopropyltriethoxysilane, ethanediamine and dodecanoyl chloride. The new stationary phase was characterized by elemental analysis. After that, a column packed with the new stationary phase was used to separate basic compounds. A commercial C18 column was also tested under the same chromatographic conditions for comparison. The results indicated that the ligand was successfully bonded to the surface of the silica and the maximum relative deviations of element contents were within 5% for carbon, nitrogen and hydrogen by three times. Furthermore, in the separation of five basic anilines and four basic pyridines, the excellent selectivity and symmetrical peak shapes provided a reference for advancing the commercialization of the new stationary phase.
A new kind of silica-bonded reserved stationary phase with s-triazine and amide polar groups embedded for HPLC was obtained by step-wise reactions of silica gel with s-triazine, γ-aminopropyltriethoxysilane, ethanediamine and dodecanoyl chloride. The new stationary phase was characterized by elemental analysis. After that, a column packed with the new stationary phase was used to separate basic compounds. A commercial C18 column was also tested under the same chromatographic conditions for comparison. The results indicated that the ligand was successfully bonded to the surface of the silica and the maximum relative deviations of element contents were within 5% for carbon, nitrogen and hydrogen by three times. Furthermore, in the separation of five basic anilines and four basic pyridines, the excellent selectivity and symmetrical peak shapes provided a reference for advancing the commercialization of the new stationary phase.
2013, 31(11): 1040-1045
doi: 10.3724/SP.J.1123.2013.05032
Abstract:
An analytical method was developed to simultaneously detect triclosan (TCS) and triclocarban (TCC) in human nails using solid phase extraction (SPE) with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Nail clippings were digested by sodium hydroxide, and then concentrated and purified with C18 cartridges. Chromatographic separation was performed on a Waters ACQUITYTM UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm) with gradient elution using methanol and water at a flow rate of 0.3 mL/min. The target compounds were determined by triple quadrupole mass spectrometer operated in the negative ion mode and quantified by isotopic-dilution technique. The satisfactory linearities (r2=0.999) was obtained over the ranges of 0.5-500.0 μg/kg for TCS and 0.1-100.0 μg/kg for TCC, with the limits of quantification (LOQs) of 2.0 μg/kg for TCS and 0.2 μg/kg for TCC. The average recoveries of the two target compounds (spiked at three concentration levels) ranged from 95.9% to 110.2%, with the relative standard deviations (RSDs) between 0.6% and 9.7% (n=6). This method can be applied in rapid detection of target contaminants in nails due to its high sensitivity, high recovery and good reproducibility. Sixty collected human nail samples were analyzed by means of the developed method. TCS and TCC were detected in all samples with content ranges of
An analytical method was developed to simultaneously detect triclosan (TCS) and triclocarban (TCC) in human nails using solid phase extraction (SPE) with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Nail clippings were digested by sodium hydroxide, and then concentrated and purified with C18 cartridges. Chromatographic separation was performed on a Waters ACQUITYTM UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm) with gradient elution using methanol and water at a flow rate of 0.3 mL/min. The target compounds were determined by triple quadrupole mass spectrometer operated in the negative ion mode and quantified by isotopic-dilution technique. The satisfactory linearities (r2=0.999) was obtained over the ranges of 0.5-500.0 μg/kg for TCS and 0.1-100.0 μg/kg for TCC, with the limits of quantification (LOQs) of 2.0 μg/kg for TCS and 0.2 μg/kg for TCC. The average recoveries of the two target compounds (spiked at three concentration levels) ranged from 95.9% to 110.2%, with the relative standard deviations (RSDs) between 0.6% and 9.7% (n=6). This method can be applied in rapid detection of target contaminants in nails due to its high sensitivity, high recovery and good reproducibility. Sixty collected human nail samples were analyzed by means of the developed method. TCS and TCC were detected in all samples with content ranges of
2013, 31(11): 1046-1050
doi: 10.3724/SP.J.1123.2013.06010
Abstract:
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of five pyrrolizidine alkaloids (PAs) (monocrotaline, senkirkine, retrorsine, seneciphylline and senecionine) in honey. The honey samples were dissolved in 0.1 mol/L hydrochloric acid solution and a strong-cation exchange column was used to purify and concentrate the target analytes. The separation of the analytes was carried out on a Phenomenex C18 column(100 mm×4.6 mm, 2.6 μm)using the mobile phases of acetonitrile and 5 mmol/L ammonium acetate-0.1% (volume percentage) formic acid aqueous solution with gradient elution. The separated compounds were detected in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI+). The calibration curves were of good linearity in the range of 1-100 μg/L (r >0.99). The limit of quantification of the method was 1.0 μg/kg. The average recoveries were between 73.1% to 107.1% at three spiked levels (1, 20 and 50 μg/kg) with the relative standard deviations(RSDs)in the range of 4.1% to 17.0%. The proposed method was applied to different kinds of honey from China, New Zealand, Spain and Australia. The samples included rape, vitex, sunflower, cotton, tilia tree, date, acacia, buckwheat, manuka and eucalyptus honey. Monocrotaline, senkirkine and retrorsine were not detected in the collected honey samples. However, seneciphylline and senecionine were found in most of the honey samples. The concentrations of seneciphylline and senecionine were 11.0-31.1 μg/kg and 8.3-29.1 μg/kg, respectively.
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of five pyrrolizidine alkaloids (PAs) (monocrotaline, senkirkine, retrorsine, seneciphylline and senecionine) in honey. The honey samples were dissolved in 0.1 mol/L hydrochloric acid solution and a strong-cation exchange column was used to purify and concentrate the target analytes. The separation of the analytes was carried out on a Phenomenex C18 column(100 mm×4.6 mm, 2.6 μm)using the mobile phases of acetonitrile and 5 mmol/L ammonium acetate-0.1% (volume percentage) formic acid aqueous solution with gradient elution. The separated compounds were detected in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI+). The calibration curves were of good linearity in the range of 1-100 μg/L (r >0.99). The limit of quantification of the method was 1.0 μg/kg. The average recoveries were between 73.1% to 107.1% at three spiked levels (1, 20 and 50 μg/kg) with the relative standard deviations(RSDs)in the range of 4.1% to 17.0%. The proposed method was applied to different kinds of honey from China, New Zealand, Spain and Australia. The samples included rape, vitex, sunflower, cotton, tilia tree, date, acacia, buckwheat, manuka and eucalyptus honey. Monocrotaline, senkirkine and retrorsine were not detected in the collected honey samples. However, seneciphylline and senecionine were found in most of the honey samples. The concentrations of seneciphylline and senecionine were 11.0-31.1 μg/kg and 8.3-29.1 μg/kg, respectively.
2013, 31(11): 1051-1056
doi: 10.3724/SP.J.1123.2013.06032
Abstract:
A systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography (HILIC) was performed. The influences of mobile phase, stationary phase and buffer salt on the retention of carbohydrates were investigated. According to the results, the retention time of carbohydrates decreased as the proportion of acetonitrile in mobile phase decreased. Increased time of carbohydrates was observed as the concentration of buffer salt in mobile phase increased. The retention behavior of carbohydrates was also affected by organic solvent and HILIC stationary phase. Furthermore, an appropriate retention equation was used in HILIC mode. The retention equation lnk=a+blnCB+cCB could quantitatively describe the retention factors of carbohydrates of plant origin with good accuracy: the relative error of the predicted time to actual time was less than 0.3%. The evaluation results could provide guidance for carbohydrates to optimize the experimental conditions in HILIC method development especially for carbohydrate separation.
A systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography (HILIC) was performed. The influences of mobile phase, stationary phase and buffer salt on the retention of carbohydrates were investigated. According to the results, the retention time of carbohydrates decreased as the proportion of acetonitrile in mobile phase decreased. Increased time of carbohydrates was observed as the concentration of buffer salt in mobile phase increased. The retention behavior of carbohydrates was also affected by organic solvent and HILIC stationary phase. Furthermore, an appropriate retention equation was used in HILIC mode. The retention equation lnk=a+blnCB+cCB could quantitatively describe the retention factors of carbohydrates of plant origin with good accuracy: the relative error of the predicted time to actual time was less than 0.3%. The evaluation results could provide guidance for carbohydrates to optimize the experimental conditions in HILIC method development especially for carbohydrate separation.
2013, 31(11): 1057-1063
doi: 10.3724/SP.J.1123.2013.05043
Abstract:
N-glycosylation of proteins is one of the most important post-translational modifications (PTM). Many diagnostic biomarkers and therapeutic targets are glycosylated proteins. However, it is still a big challenge to identify glycoproteins in human plasma, because of the high dynamic range and microheterogeneity of glycosylation. In this work, hydrophilic interaction liquid chromatography (HILIC) enrichment, high-pH reversed-phase prefractionation and high accurate mass spectrometry (MS) analysis were combined to profile the N-glycoproteins in human plasma. In total, 637 N-glycosites from 299 glycoproteins (protein groups) were identified. There were also 31 glycoforms recognized after HILIC enrichment and MS analysis. Among the results, 107 glycosylation sites (16.8%) are newly found. This study provided a simple and reliable strategy for exploring potential N-glycoprotein biomarkers from complicated biological systems.
N-glycosylation of proteins is one of the most important post-translational modifications (PTM). Many diagnostic biomarkers and therapeutic targets are glycosylated proteins. However, it is still a big challenge to identify glycoproteins in human plasma, because of the high dynamic range and microheterogeneity of glycosylation. In this work, hydrophilic interaction liquid chromatography (HILIC) enrichment, high-pH reversed-phase prefractionation and high accurate mass spectrometry (MS) analysis were combined to profile the N-glycoproteins in human plasma. In total, 637 N-glycosites from 299 glycoproteins (protein groups) were identified. There were also 31 glycoforms recognized after HILIC enrichment and MS analysis. Among the results, 107 glycosylation sites (16.8%) are newly found. This study provided a simple and reliable strategy for exploring potential N-glycoprotein biomarkers from complicated biological systems.
2013, 31(11): 1064-1070
doi: 10.3724/SP.J.1123.2013.04040
Abstract:
A visual, rapid and accurate moving reaction boundary titration (MRBT) method was used for the determination of the total protein in soya-bean milk. During the process, moving reaction boundary (MRB) was formed by hydroxyl ions in the catholyte and soya-bean milk proteins immobilized in polyacrylamide gel (PAG), and an acid-base indicator was used to denote the boundary motion. The velocity of MRB has a relationship with protein concentration, which was used to obtain a standard curve. By paired t-test, there was no significant difference of the protein content between MRBT and Kjeldahl method at 95% confidence interval. The procedure of MRBT method required about 10 min, and it had linearity in the range of 2.0-14.0 g/L, low limit of detection (0.05 g/L), good precision (RSD of intra-day<1.90% and inter-day<4.39%), and high recoveries (97.41%-99.91%). In addition, non-protein nitrogen (NPN) such as melamine added into the soya-bean milk had weak influence on MRBT results.
A visual, rapid and accurate moving reaction boundary titration (MRBT) method was used for the determination of the total protein in soya-bean milk. During the process, moving reaction boundary (MRB) was formed by hydroxyl ions in the catholyte and soya-bean milk proteins immobilized in polyacrylamide gel (PAG), and an acid-base indicator was used to denote the boundary motion. The velocity of MRB has a relationship with protein concentration, which was used to obtain a standard curve. By paired t-test, there was no significant difference of the protein content between MRBT and Kjeldahl method at 95% confidence interval. The procedure of MRBT method required about 10 min, and it had linearity in the range of 2.0-14.0 g/L, low limit of detection (0.05 g/L), good precision (RSD of intra-day<1.90% and inter-day<4.39%), and high recoveries (97.41%-99.91%). In addition, non-protein nitrogen (NPN) such as melamine added into the soya-bean milk had weak influence on MRBT results.
2013, 31(11): 1071-1075
doi: 10.3724/SP.J.1123.2013.05048
Abstract:
A novel method was developed for the determination of seven triazine herbicides in environmental water samples by magnetic solid-phase extraction with graphene-based magnetic nanoparticles (G-Fe3O4 MNPs) as the adsorbent coupled with gas chromatography-mass spectrometry detection. The main factors influencing the extraction efficiency including the amount of G-Fe3O4, the extraction time, the pH and the ionic strength of sample solution and the desorption conditions were optimized. Under the optimized experimental conditions, the enrichment factors of the method for the analytes were in the range from 574 to 968; the linearities of the method ranged from 0.01 to 10.0 μg/L for simazine, propazine, metribuzin, simetryn and cyanazine, from 0.05 to 10.0 μg/L for atrazine and from 0.01 to 8.0 μg/L for prometryn, with the correlation coefficients (r) ranging from 0.9968 to 0.9998. The limits of detection were in the range between 1.0 and 5.0 ng/L. Good reproducibilities were obtained with the relative standard deviations below 10.5%. The developed method was applied to the analysis of the triazine herbicides in different water samples (lake, well and tap). The recoveries of the method were in the range from 79.8% to 118.3% at the spiked levels of 0.5 μg/L and 2.0 μg/L. The results indicated that the developed method can be used as a simple and efficient technique for the determination of the triazine herbicides in environmental water samples.
A novel method was developed for the determination of seven triazine herbicides in environmental water samples by magnetic solid-phase extraction with graphene-based magnetic nanoparticles (G-Fe3O4 MNPs) as the adsorbent coupled with gas chromatography-mass spectrometry detection. The main factors influencing the extraction efficiency including the amount of G-Fe3O4, the extraction time, the pH and the ionic strength of sample solution and the desorption conditions were optimized. Under the optimized experimental conditions, the enrichment factors of the method for the analytes were in the range from 574 to 968; the linearities of the method ranged from 0.01 to 10.0 μg/L for simazine, propazine, metribuzin, simetryn and cyanazine, from 0.05 to 10.0 μg/L for atrazine and from 0.01 to 8.0 μg/L for prometryn, with the correlation coefficients (r) ranging from 0.9968 to 0.9998. The limits of detection were in the range between 1.0 and 5.0 ng/L. Good reproducibilities were obtained with the relative standard deviations below 10.5%. The developed method was applied to the analysis of the triazine herbicides in different water samples (lake, well and tap). The recoveries of the method were in the range from 79.8% to 118.3% at the spiked levels of 0.5 μg/L and 2.0 μg/L. The results indicated that the developed method can be used as a simple and efficient technique for the determination of the triazine herbicides in environmental water samples.
2013, 31(11): 1076-1080
doi: 10.3724/SP.J.1123.2013.06008
Abstract:
A novel method for simultaneous determination of eight organochlorine pesticides in aqueous samples by solvent demulsification-dispersive liquid-liquid microextraction based on solidification of floating organic drop coupled with gas chromatography-mass spectrometry (GC-MS) was established. A mixture of extractant (n-hexadecane) and dispersive agent (acetone) at the ratio of 1/5 (v/v) was injected into aqueous sample to form an emulsion and an extraction process was accomplished. The demulsifier (750 μ L acetone) was then injected to break up the emulsion. The two phases were separated quickly without centrifugation. After being solidified in an ice-bath, the upper layer (n-hexadecane) was transferred into an Eppendorf tube and analyzed by GC-MS after melted at room temperature. Factors affecting extraction efficiency such as the type and volume of extractant, dispersive agent and demulsifier, also ionic strength and pH value of extraction system were studied. Under the optimized conditions, the working curve of the proposed method provided a good linearity in the range of 0.025-2.00 μg/L (r=0.9995-0.9999). The detection limits of the organochlorine pesticides calculated by Hubaux-Vos method were 0.012-0.024 μg/L and the relative standard deviations (RSDs) ranged from 3.15% to 4.53%. The enrichment factors (EF) were 96-101. When the method was applied to the determination of farmland water, the average spiked recoveries were 96.77%-102.93% with the relative standard deviations of 2.68%-4.86%. The proposed method is sensitive and fast. It also has the advantage of little organic solvent consumption so that it is friendly to environment and suitable for batch analysis of organochlorine pesticides in aqueous samples. Meanwhile, it provides technical and methodological support for achieving the automation of sample pretreatment.
A novel method for simultaneous determination of eight organochlorine pesticides in aqueous samples by solvent demulsification-dispersive liquid-liquid microextraction based on solidification of floating organic drop coupled with gas chromatography-mass spectrometry (GC-MS) was established. A mixture of extractant (n-hexadecane) and dispersive agent (acetone) at the ratio of 1/5 (v/v) was injected into aqueous sample to form an emulsion and an extraction process was accomplished. The demulsifier (750 μ L acetone) was then injected to break up the emulsion. The two phases were separated quickly without centrifugation. After being solidified in an ice-bath, the upper layer (n-hexadecane) was transferred into an Eppendorf tube and analyzed by GC-MS after melted at room temperature. Factors affecting extraction efficiency such as the type and volume of extractant, dispersive agent and demulsifier, also ionic strength and pH value of extraction system were studied. Under the optimized conditions, the working curve of the proposed method provided a good linearity in the range of 0.025-2.00 μg/L (r=0.9995-0.9999). The detection limits of the organochlorine pesticides calculated by Hubaux-Vos method were 0.012-0.024 μg/L and the relative standard deviations (RSDs) ranged from 3.15% to 4.53%. The enrichment factors (EF) were 96-101. When the method was applied to the determination of farmland water, the average spiked recoveries were 96.77%-102.93% with the relative standard deviations of 2.68%-4.86%. The proposed method is sensitive and fast. It also has the advantage of little organic solvent consumption so that it is friendly to environment and suitable for batch analysis of organochlorine pesticides in aqueous samples. Meanwhile, it provides technical and methodological support for achieving the automation of sample pretreatment.
2013, 31(11): 1081-1086
doi: 10.3724/SP.J.1123.2013.05005
Abstract:
An effective method was developed to determine phenolic compounds in soil by ultrasonic extraction-gas chromatography (GC). The soil sample was extracted with methylene dichloride-hexane (2:1, v/v) for 3 min with the extraction temperature lower than 50 ℃ for 3 times. The extract was purified by alkaline aqueous solution (pH >12), and the phenolic compounds were dissolved in aqueous solution. After the organic solution was discarded, the aqueous solution was adjusted to pH<3 and subsequently extracted with methylene dichloride-ethyl acetate (4:1, v/v) twice. The analytes were determined by GC-FID and quantified by external standard method. The limits of quantification for all tested phenolic compounds were 0.01-0.06 mg/kg in about 10 g soil samples. The recoveries were between 62.9% and 111.4% with the relative standard deviations (RSDs) in the range of 4.3%-24.0% (n=6). The results showed that this method is sensitive, accurate, and suitable for the determination of the 21 phenolic compounds in soil.
An effective method was developed to determine phenolic compounds in soil by ultrasonic extraction-gas chromatography (GC). The soil sample was extracted with methylene dichloride-hexane (2:1, v/v) for 3 min with the extraction temperature lower than 50 ℃ for 3 times. The extract was purified by alkaline aqueous solution (pH >12), and the phenolic compounds were dissolved in aqueous solution. After the organic solution was discarded, the aqueous solution was adjusted to pH<3 and subsequently extracted with methylene dichloride-ethyl acetate (4:1, v/v) twice. The analytes were determined by GC-FID and quantified by external standard method. The limits of quantification for all tested phenolic compounds were 0.01-0.06 mg/kg in about 10 g soil samples. The recoveries were between 62.9% and 111.4% with the relative standard deviations (RSDs) in the range of 4.3%-24.0% (n=6). The results showed that this method is sensitive, accurate, and suitable for the determination of the 21 phenolic compounds in soil.
2013, 31(11): 1087-1092
doi: 10.3724/SP.J.1123.2013.05042
Abstract:
A high performance liquid chromatography-electrospray ionization mass spectrometry method was developed for the determination of aconite alkaloids. It was used to investigate the degradation of alkaloids of Radix Aconiti Lateralis Preparata during decoction. Six alkaline degradation products were identified, and the degradation regularity of diester-diterpenoid alkaloids was confirmed during the test using standards. The dynamic changes of the amount of aconite alkaloids in the decoction of Radix Aconiti Lateralis Preparata were supervised. Along with the increase of decoction time, the concentrations of diester-diterpenoid alkaloids and lipo-alkaloid decreased significantly. The results can provide a scientific basis for the safety use of aconite.
A high performance liquid chromatography-electrospray ionization mass spectrometry method was developed for the determination of aconite alkaloids. It was used to investigate the degradation of alkaloids of Radix Aconiti Lateralis Preparata during decoction. Six alkaline degradation products were identified, and the degradation regularity of diester-diterpenoid alkaloids was confirmed during the test using standards. The dynamic changes of the amount of aconite alkaloids in the decoction of Radix Aconiti Lateralis Preparata were supervised. Along with the increase of decoction time, the concentrations of diester-diterpenoid alkaloids and lipo-alkaloid decreased significantly. The results can provide a scientific basis for the safety use of aconite.
2013, 31(11): 1093-1101
doi: 10.3724/SP.J.1123.2013.05008
Abstract:
A method for the determination of alditols in foods by ion chromatography-mass spectrometry (IC-MS) has been developed. The samples were extracted and cleaned up with the solid phase extraction (SPE). Then, the ion chromatographic separation was performed on a CarboPar MA1 column. The alditols were determined by MS with the selected ion monitoring (SIM) mode and quantified by the external standard method. The calibration curves showed good linearity in the certain ranges with the correlation coefficients (R2) greater than 0.99. The limits of quantification (S/N=10) of erythritol, xylitol, D-sorbitol, D-mannitol, lactitol, maltitol were 0.98, 1.99, 2.24, 5.92, 13.56, 13.21 mg/kg and the limits of detection (S/N=3) were 0.28, 0.59, 0.71, 1.74, 4.14, 4.03 mg/kg, respectively. The spiked recoveries of the alditols in the foods at different levels were in the range of 82.5%-108.0% with the relative standard deviations (RSDs) of 1.5%-7.6%. The sensitivity, accuracy and precision of the method meet the technical standards of the determination. The method can be applied to the determination of alditols in foods.
A method for the determination of alditols in foods by ion chromatography-mass spectrometry (IC-MS) has been developed. The samples were extracted and cleaned up with the solid phase extraction (SPE). Then, the ion chromatographic separation was performed on a CarboPar MA1 column. The alditols were determined by MS with the selected ion monitoring (SIM) mode and quantified by the external standard method. The calibration curves showed good linearity in the certain ranges with the correlation coefficients (R2) greater than 0.99. The limits of quantification (S/N=10) of erythritol, xylitol, D-sorbitol, D-mannitol, lactitol, maltitol were 0.98, 1.99, 2.24, 5.92, 13.56, 13.21 mg/kg and the limits of detection (S/N=3) were 0.28, 0.59, 0.71, 1.74, 4.14, 4.03 mg/kg, respectively. The spiked recoveries of the alditols in the foods at different levels were in the range of 82.5%-108.0% with the relative standard deviations (RSDs) of 1.5%-7.6%. The sensitivity, accuracy and precision of the method meet the technical standards of the determination. The method can be applied to the determination of alditols in foods.
2013, 31(11): 1102-1105
doi: 10.3724/SP.J.1123.2013.07033
Abstract:
A high performance liquid chromatographic (HPLC) method was proposed to simultaneously determine four common nonprotein nitrogen substances, including creatine (Cr), creatinine (Cn), uric acid (Ua) and pseudouridine (Pu) in urine. After proteins being removed by acetone precipitation method, freeze drying and redissolving, the urine samples were analyzed by HPLC. Chromatographic separation was performed on a Waters RP18 Column (150 mm×4.60 mm, 3.5 μm) in gradient elution mode using 10.0 mmol/L KH2PO4 solution (pH 4.78) and acetonitrile as mobile phases at a flow rate of 0.8 mL/min. The samples were detected at 220 nm. Rapid separation was achieved within 7 min. Under the optimized conditions, good linearities of four common nonprotein nitrogen substances were obtained in the range of 0.1-250 mg/L. The detection limits were 9.31 (Cr), 26.19 (Cn), 4.70 (Ua), and 6.30 (Pu) μg/L and the recoveries were in the range of 81%-111% with the relative standard deviations of 0.23%-2.78% (n=3). The results demonstrate that this method is simple, rapid and accurate with good reproducibility, and can provide early diagnosis and preliminary judgment for type 2 diabetes mellitus (T2DM) patients with renal damage.
A high performance liquid chromatographic (HPLC) method was proposed to simultaneously determine four common nonprotein nitrogen substances, including creatine (Cr), creatinine (Cn), uric acid (Ua) and pseudouridine (Pu) in urine. After proteins being removed by acetone precipitation method, freeze drying and redissolving, the urine samples were analyzed by HPLC. Chromatographic separation was performed on a Waters RP18 Column (150 mm×4.60 mm, 3.5 μm) in gradient elution mode using 10.0 mmol/L KH2PO4 solution (pH 4.78) and acetonitrile as mobile phases at a flow rate of 0.8 mL/min. The samples were detected at 220 nm. Rapid separation was achieved within 7 min. Under the optimized conditions, good linearities of four common nonprotein nitrogen substances were obtained in the range of 0.1-250 mg/L. The detection limits were 9.31 (Cr), 26.19 (Cn), 4.70 (Ua), and 6.30 (Pu) μg/L and the recoveries were in the range of 81%-111% with the relative standard deviations of 0.23%-2.78% (n=3). The results demonstrate that this method is simple, rapid and accurate with good reproducibility, and can provide early diagnosis and preliminary judgment for type 2 diabetes mellitus (T2DM) patients with renal damage.
2013, 31(11): 1106-1111
doi: 10.3724/SP.J.1123.2013.05018
Abstract:
A high performance liquid chromatographic method was developed for the simultaneous determination of 10 synthetic colorants in cosmetics. The cosmetics were extracted by the ultrasonic technique with tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) and methanol sequentially. Then the extracts were centrifuged for purification and separated on an Eclipse XDB-C18 column (150 mm×4.6 mm, 5 μm) with gradient elution by acetonitrile and 0.02 mol/L ammonium acetate (pH 4.60, adjusted with acetic acid). A diode array detector was used to determine the colorants with the wavelengths ranging from 417 nm to 640 nm. The linear relationships of the 10 colorants between the peak areas and the mass concentrations were obtained in the range of 0.5-20.0 mg/L (r >0.999). The limits of quantitation ranged from 10 to 20 mg/kg. The average recoveries at three concentration levels ranged from 92.9% to 108.8% with the relative standard deviations in the range of 0.5% to 6.1% (n=6). The method is simple, rapid and sensitive. It is suitable for the simultaneous determination of the 10 colorants in the oil cosmetics, cream cosmetics and powder cosmetics.
A high performance liquid chromatographic method was developed for the simultaneous determination of 10 synthetic colorants in cosmetics. The cosmetics were extracted by the ultrasonic technique with tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) and methanol sequentially. Then the extracts were centrifuged for purification and separated on an Eclipse XDB-C18 column (150 mm×4.6 mm, 5 μm) with gradient elution by acetonitrile and 0.02 mol/L ammonium acetate (pH 4.60, adjusted with acetic acid). A diode array detector was used to determine the colorants with the wavelengths ranging from 417 nm to 640 nm. The linear relationships of the 10 colorants between the peak areas and the mass concentrations were obtained in the range of 0.5-20.0 mg/L (r >0.999). The limits of quantitation ranged from 10 to 20 mg/kg. The average recoveries at three concentration levels ranged from 92.9% to 108.8% with the relative standard deviations in the range of 0.5% to 6.1% (n=6). The method is simple, rapid and sensitive. It is suitable for the simultaneous determination of the 10 colorants in the oil cosmetics, cream cosmetics and powder cosmetics.
2013, 31(11): 1112-1115
doi: 10.3724/SP.J.1123.2013.09035
Abstract:
A sensitive high performance liquid chromatography (HPLC)-laser induced fluorescence detection (LIFD) method was developed for the determination of amines. The derivatization and separation conditions were investigated. Under the optimized conditions, spermidine, putrescine and histamine were analyzed. The limits of detection (LODs) of the three biogenic amines (S/N=3) were as low as 10-10 mol/L. This method showed excellent stability. The RSDs of retention times and peak areas of the three biogenic amines were lower than 0.3% and 3%, respectively. This method was applied in biogenic amine analysis in water samples, and the average recoveries were in the range of 94.99%-104.7%. Furthermore, the amines in seven tea samples were analyzed by this method, and satisfactory results were achieved. The developed assay is of excellent sensitivity and good reproducibility, which can be used in the analysis of the amines in water samples.
A sensitive high performance liquid chromatography (HPLC)-laser induced fluorescence detection (LIFD) method was developed for the determination of amines. The derivatization and separation conditions were investigated. Under the optimized conditions, spermidine, putrescine and histamine were analyzed. The limits of detection (LODs) of the three biogenic amines (S/N=3) were as low as 10-10 mol/L. This method showed excellent stability. The RSDs of retention times and peak areas of the three biogenic amines were lower than 0.3% and 3%, respectively. This method was applied in biogenic amine analysis in water samples, and the average recoveries were in the range of 94.99%-104.7%. Furthermore, the amines in seven tea samples were analyzed by this method, and satisfactory results were achieved. The developed assay is of excellent sensitivity and good reproducibility, which can be used in the analysis of the amines in water samples.
2013, 31(11): 1116-1128
doi: 10.3724/SP.J.1123.2013.03044
Abstract:
With a combination of QuEChERS method and gas chromatography-tandem mass spectrometry (GC-MS/MS) technique, three sample treatment methods (solvent exchange method, toluene dilution method, hexane liquid-liquid extraction method) were established to analyse more than one hundred pesticide residues in tobacco. The 155 pesticide analytes contained 58 organophosphorus, 28 organochlorine, 10 pyrethroids, 10 acyl amide, 11 carbamate, 7 dinitroaniline and 31 other family pesticides. Comparison of the three treatment methods was investigated on performances including matrix effect, co-extracted matrix, peak interference, recovery and the limit of quantification (LOQ). The hexane liquid-liquid extraction method gave the cleanest extract but poorer recovery; the solvent exchange and toluene dilution method could guarantee recoveries in the range of 70% and 120% for most of the 155 pesticides. We found that organophosphorus, acyl amide and carbamate pesticides exhibited relative strong matrix effects compared with organochlorine and pyrethroid pesticides. Toluene dilution method was recommended to analyse organophosphorus pesticides, and hexane liquid-liquid extraction (LLE) method was recommended to analyse organochlorine and pyrethroid pesticides.
With a combination of QuEChERS method and gas chromatography-tandem mass spectrometry (GC-MS/MS) technique, three sample treatment methods (solvent exchange method, toluene dilution method, hexane liquid-liquid extraction method) were established to analyse more than one hundred pesticide residues in tobacco. The 155 pesticide analytes contained 58 organophosphorus, 28 organochlorine, 10 pyrethroids, 10 acyl amide, 11 carbamate, 7 dinitroaniline and 31 other family pesticides. Comparison of the three treatment methods was investigated on performances including matrix effect, co-extracted matrix, peak interference, recovery and the limit of quantification (LOQ). The hexane liquid-liquid extraction method gave the cleanest extract but poorer recovery; the solvent exchange and toluene dilution method could guarantee recoveries in the range of 70% and 120% for most of the 155 pesticides. We found that organophosphorus, acyl amide and carbamate pesticides exhibited relative strong matrix effects compared with organochlorine and pyrethroid pesticides. Toluene dilution method was recommended to analyse organophosphorus pesticides, and hexane liquid-liquid extraction (LLE) method was recommended to analyse organochlorine and pyrethroid pesticides.
2013, 31(11): 1129-1133
doi: 10.3724/SP.J.1123.2013.06006
Abstract:
A simultaneous determination method for ethyl carbamate (EC) and chloropropanols (3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD)) in flavorings was developed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). After spiked with internal standard, the sample was extracted by matrix solid-phase dispersion extraction technique with an ExtrelutTM NT column. Hexane was used to wash the fat soluble matrix interferences and then an ethyl acetate-ethyl ether (20:80, v/v) mixture was added to elute the analytes. The concentrated extract was detected by GC-MS/MS in multiple reaction monitoring (MRM) mode. The limits of detection (LODs) were 2, 5 and 5 μg/kg for EC, 3-MCPD and 2-MCPD, respectively. The linear ranges were 5-1000 μg/kg (r=0.9997), 10-1000 μg/kg (r=0.9991) and 10-1000 μg/kg (r=0.9995) for EC, 3-MCPD and 2-MCPD, respectively. In soy sauce, yellow rice wine, salami sauce and flavoring of instant noodle matrices, the recoveries (RSDs, n=7) in MRM mode at the levels of 20, 100 and 400 μg/kg were 87.7%-104% (4.3%-10.7%), 90.1%-109% (2.6%-10.2%), and 90.9%-103% (3.0%-9.5%), respectively. EC, 3-MCPD and 2-MCPD were found in some real samples of the soy sauce, wine and flavoring of instant noodle. EC or 3-MCPD was found in some of the salami samples. The method is accurate, fast and suitable for the simultaneous determination of EC, 3-MCPD and 2-MCPD in flavorings.
A simultaneous determination method for ethyl carbamate (EC) and chloropropanols (3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD)) in flavorings was developed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). After spiked with internal standard, the sample was extracted by matrix solid-phase dispersion extraction technique with an ExtrelutTM NT column. Hexane was used to wash the fat soluble matrix interferences and then an ethyl acetate-ethyl ether (20:80, v/v) mixture was added to elute the analytes. The concentrated extract was detected by GC-MS/MS in multiple reaction monitoring (MRM) mode. The limits of detection (LODs) were 2, 5 and 5 μg/kg for EC, 3-MCPD and 2-MCPD, respectively. The linear ranges were 5-1000 μg/kg (r=0.9997), 10-1000 μg/kg (r=0.9991) and 10-1000 μg/kg (r=0.9995) for EC, 3-MCPD and 2-MCPD, respectively. In soy sauce, yellow rice wine, salami sauce and flavoring of instant noodle matrices, the recoveries (RSDs, n=7) in MRM mode at the levels of 20, 100 and 400 μg/kg were 87.7%-104% (4.3%-10.7%), 90.1%-109% (2.6%-10.2%), and 90.9%-103% (3.0%-9.5%), respectively. EC, 3-MCPD and 2-MCPD were found in some real samples of the soy sauce, wine and flavoring of instant noodle. EC or 3-MCPD was found in some of the salami samples. The method is accurate, fast and suitable for the simultaneous determination of EC, 3-MCPD and 2-MCPD in flavorings.
2013, 31(11): 1134-1139
doi: 10.3724/SP.J.1123.2013.05047
Abstract:
Gas chromatography-mass spectrometry (GC-MS) qualitative characterization of C5-C7 alkenes in gasoline from methanol to olefins (MTO) was investigated in detail. It showed that the retention indices of 49 alkenes, 11 alkadienes and 9 cycloalkenes, a total of 69 C5-C7 isomeric alkenes were determined and qualitatively confirmed. The retention indices of all C5-C7 alkenes in MTO gasoline were measured on polydimethylsiloxane as the stationary phase. According to the library of retention indices by GC-MS characterization, the contents of C5-C7 alkenes in MTO gasoline were analyzed by GC and characterized by its composition of hydrocarbon categories. The results of quantitative analysis showed that the composition of MTO gasoline mainly consisted of C5-C7 alkenes, and a small amount of alkadienes and cycloalkenes. The contents of alkanes and cycloalkanes existed in MTO gasoline were very low. The study of the composition is helpful for the comprehensive application of MTO gasoline.
Gas chromatography-mass spectrometry (GC-MS) qualitative characterization of C5-C7 alkenes in gasoline from methanol to olefins (MTO) was investigated in detail. It showed that the retention indices of 49 alkenes, 11 alkadienes and 9 cycloalkenes, a total of 69 C5-C7 isomeric alkenes were determined and qualitatively confirmed. The retention indices of all C5-C7 alkenes in MTO gasoline were measured on polydimethylsiloxane as the stationary phase. According to the library of retention indices by GC-MS characterization, the contents of C5-C7 alkenes in MTO gasoline were analyzed by GC and characterized by its composition of hydrocarbon categories. The results of quantitative analysis showed that the composition of MTO gasoline mainly consisted of C5-C7 alkenes, and a small amount of alkadienes and cycloalkenes. The contents of alkanes and cycloalkanes existed in MTO gasoline were very low. The study of the composition is helpful for the comprehensive application of MTO gasoline.
