In this study,we investigated the effect of sample pretreatments(ultrasonication and alkaline extraction)on total organic carbon(TOC)measurements for water samples containing suspended solids(SS)of four different orig...In this study,we investigated the effect of sample pretreatments(ultrasonication and alkaline extraction)on total organic carbon(TOC)measurements for water samples containing suspended solids(SS)of four different origins(algae,soil,sewage sludge,and leaf litter)to more clearly assess the impact of particulate organic carbon(POC)in water.The effects each of ultrasonication(power,pulse,etc.)and alkaline extraction condition(concentration,time,etc.)on the TOC recovery and precision were investigated,and the results were compared with those of a new sample pre treatment method combining both methods.Alkaline treatment(0.01 mol/L NaOH)showed higher precision than ultrasonication(100/5 on/off pulse),and notably,the differences among the measured TOC values in samples of different origins were also further reduced in the alkaline treatment.This suggests that the ultrasonic pretreatment results can be mainly attributed to the increase in POC recovery through particle size reduction,whereas the alkaline treatment results are achieved through the enhancement of POC solubilization.It is also particularly noteworthy that a higher TOC recovery of 87.6%±7.4%with a higher precision of 8.4%could be obtained using the combined method,compared to each treatment(ultrasonic:TOC recovery 34.7%,relative standard deviation 63.1%;alkaline:49.6%and 23.0%,respectively).Thus,simultaneous pretreatment with ultrasonication and alkaline extraction is expected to increase the oxidation rate of organic matter and the homogeneity of the samples,minimizing the loss of POC measurement values,and thereby improving the reliability of the TOC measurements of water samples containing SS.展开更多
对碱溶酸沉法、超声辅助碱提法和蛋白酶法3种工艺制备的芝麻饼粕蛋白质PA、PU和PE的理化和功能性质进行了研究,结果表明3种工艺制备的芝麻饼粕蛋白质氨基酸组成无显著差异,除赖氨酸含量较低外,其他必需氨基酸组成均接近或高于FAO/WHO模...对碱溶酸沉法、超声辅助碱提法和蛋白酶法3种工艺制备的芝麻饼粕蛋白质PA、PU和PE的理化和功能性质进行了研究,结果表明3种工艺制备的芝麻饼粕蛋白质氨基酸组成无显著差异,除赖氨酸含量较低外,其他必需氨基酸组成均接近或高于FAO/WHO模式;芝麻饼粕蛋白的相对分子质量大小顺序为PA>PU>PE。芝麻饼粕蛋白质的溶解性、持水性、持油性、乳化性、起泡性及起泡稳定性大小顺序为:PE>PU>PA,且芝麻饼粕蛋白质的p H-乳化性曲线与p H-溶解性曲线相似,溶解度和乳化性在等电点(p H 4)时最低。展开更多
将超声辅助碱液分解杂质与溶剂萃取相结合,采用气相色谱-电子捕获检测（GC-ECD）建立了一种快速高效净化、萃取海洋沉积物中8种常见多溴联苯醚（PBDEs）的分析方法。样品在2.00 mol/L Na OH甲醇溶液中超声30 m in,经正己烷萃取、单层硅...将超声辅助碱液分解杂质与溶剂萃取相结合,采用气相色谱-电子捕获检测（GC-ECD）建立了一种快速高效净化、萃取海洋沉积物中8种常见多溴联苯醚（PBDEs）的分析方法。样品在2.00 mol/L Na OH甲醇溶液中超声30 m in,经正己烷萃取、单层硅胶净化、正己烷洗脱、旋蒸浓缩后定容至100μL,采用GC-ECD分析。结果表明,PBDEs各单体的加标回收率为63.6%～110.3%,相对标准偏差（RSD）为1.7%～15.5%（n=5）;十溴联苯醚（BDE-209）的检出限为0.097 ng/g,其他7种单体的检出限为0.002～0.011 ng/g（信噪比为3）。该方法的准确度和精密度较高,稳定性和回收率良好,可满足沉积物中PBDEs的分析要求。利用建立的方法测定了渤海表层沉积物中PBDEs的含量,8种PBDEs总含量在1.566～6.760 ng/g之间,其中BDE-209的含量为1.461～6.438 ng/g,总体呈现出由近岸向远岸递减的趋势,表明人为活动、表层冲刷和陆地河流的输入对渤海地区PBDEs的含量有重要影响。展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(No.2017R1A2A2A09069617)the Korea Ministry of Environment as a“Global Top Project”(No.2016002210005)
文摘In this study,we investigated the effect of sample pretreatments(ultrasonication and alkaline extraction)on total organic carbon(TOC)measurements for water samples containing suspended solids(SS)of four different origins(algae,soil,sewage sludge,and leaf litter)to more clearly assess the impact of particulate organic carbon(POC)in water.The effects each of ultrasonication(power,pulse,etc.)and alkaline extraction condition(concentration,time,etc.)on the TOC recovery and precision were investigated,and the results were compared with those of a new sample pre treatment method combining both methods.Alkaline treatment(0.01 mol/L NaOH)showed higher precision than ultrasonication(100/5 on/off pulse),and notably,the differences among the measured TOC values in samples of different origins were also further reduced in the alkaline treatment.This suggests that the ultrasonic pretreatment results can be mainly attributed to the increase in POC recovery through particle size reduction,whereas the alkaline treatment results are achieved through the enhancement of POC solubilization.It is also particularly noteworthy that a higher TOC recovery of 87.6%±7.4%with a higher precision of 8.4%could be obtained using the combined method,compared to each treatment(ultrasonic:TOC recovery 34.7%,relative standard deviation 63.1%;alkaline:49.6%and 23.0%,respectively).Thus,simultaneous pretreatment with ultrasonication and alkaline extraction is expected to increase the oxidation rate of organic matter and the homogeneity of the samples,minimizing the loss of POC measurement values,and thereby improving the reliability of the TOC measurements of water samples containing SS.
文摘对碱溶酸沉法、超声辅助碱提法和蛋白酶法3种工艺制备的芝麻饼粕蛋白质PA、PU和PE的理化和功能性质进行了研究,结果表明3种工艺制备的芝麻饼粕蛋白质氨基酸组成无显著差异,除赖氨酸含量较低外,其他必需氨基酸组成均接近或高于FAO/WHO模式;芝麻饼粕蛋白的相对分子质量大小顺序为PA>PU>PE。芝麻饼粕蛋白质的溶解性、持水性、持油性、乳化性、起泡性及起泡稳定性大小顺序为:PE>PU>PA,且芝麻饼粕蛋白质的p H-乳化性曲线与p H-溶解性曲线相似,溶解度和乳化性在等电点(p H 4)时最低。
文摘将超声辅助碱液分解杂质与溶剂萃取相结合,采用气相色谱-电子捕获检测（GC-ECD）建立了一种快速高效净化、萃取海洋沉积物中8种常见多溴联苯醚（PBDEs）的分析方法。样品在2.00 mol/L Na OH甲醇溶液中超声30 m in,经正己烷萃取、单层硅胶净化、正己烷洗脱、旋蒸浓缩后定容至100μL,采用GC-ECD分析。结果表明,PBDEs各单体的加标回收率为63.6%～110.3%,相对标准偏差（RSD）为1.7%～15.5%（n=5）;十溴联苯醚（BDE-209）的检出限为0.097 ng/g,其他7种单体的检出限为0.002～0.011 ng/g（信噪比为3）。该方法的准确度和精密度较高,稳定性和回收率良好,可满足沉积物中PBDEs的分析要求。利用建立的方法测定了渤海表层沉积物中PBDEs的含量,8种PBDEs总含量在1.566～6.760 ng/g之间,其中BDE-209的含量为1.461～6.438 ng/g,总体呈现出由近岸向远岸递减的趋势,表明人为活动、表层冲刷和陆地河流的输入对渤海地区PBDEs的含量有重要影响。
