| 查看: 1407 | 回复: 8 | |||
| 本帖产生 1 个 翻译EPI ，点击这里进行查看 | |||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | |||
[交流]
求助一段英语翻译
|
|||
|
A previous cLC method, involving large injection volumes (20 μL) and on-column focusing techniques, provided a suitable sensitivity using an Inertsil? C8 capillary column, DAD and gradient elution. This method showed that composition of the focusing solution, mobile phase and pH have remarkable effects on HA separation. In order to improve this separation, an isocratic cLC method compatible with MS detection was developed and the influence of several chromatographic factors on separation quality evaluated. Different reversed-phase packings such as Luna? C8, Luna? C18, Synergi? Max-RP (C12) and Synergi Fusion (C18 and polar embedded group) were tested using UV-DAD detection. These columns were chosen due to their high efficiencies and bonded phase surface coverage. Considering the different particle sizes, flow rate was set at 15 μL min?1 for both Synergi Fusion? and Synergi? Max-RP, 12 and 9 μL min?1 for Luna? C8 and Luna? C18 columns respectively. Chromatographic conditions were optimized using experimental design methodologies such as central composite design. Factors and ranges selected for the optimization of mobile phase composition were ACN (11.6–28.4%), ammonium acetate concentration (13.2–46.8 mM) and buffer pH (3.6–4.4). Response variables were expressed in terms of resolution, calculated at baseline, between the worst resolved peak pair NH–H (Rs,min), and retention time of the last eluting peak (tend). From the obtained equations, it could be concluded that Rs,min was significantly affected by both ACN percentage and pH while tend only by ACN. In addition, the ammonium acetate concentration had no significant effect on separation. Chromatographic separation efficiency was optimized for Rs,min ≥ 2 and minimum tend value. Luna? C8 capillary column provided poor resolution. Luna? C18 and Synergi? Max-RP columns provided similar Rs,min to Synergi? Fusion but higher efficiencies. However, Synergi? Max-RP column provided poor peak symmetry. Therefore, Luna? C18 column was selected for further optimization with the quadrupole MS detector. Taking into account the instrumental limitations of the MS capillary nebulizer, the ammonium acetate concentration in the mobile phase was fixed to 5 mM. Chromatographic separation was optimized using multifactorial design. Factors and ranges selected were ACN (12–18%) and pH (3.6–4.1). For the injection, buffered focusing solutions with 5% MeOH were used. Table 1 includes the values of the experimental responses (Rs,min and tend), which were fitted into the following normalized polynomial equations: (1)Rs,min=1.74?0.51pH?1.35ACN?0.06pH2+0.39pH ACN+0.40ACN2 (2)tend=12.18+0.18pH?11.02ACN+0.76pH2?0.94pH ACN+4.83 ACN2 Determination coefficients were 0.988 and 0.992 for Rs,min and tend respectively, showing the reliability of the equations. In the studied domain, both ACN percentage and pH affected significantly to Rs,min (p values 0.0000 and 0.0002 respectively) (Eq. (1)) while ACN (%) affected only tend (p value 0.0000 and 0.0005 for the single and quadratic term respectively) (Eq. (2)). As can be expected, the interactions between factors (ACN-pH) were significant only for Rs,min response (p = 0.0033). In Fig. 1 it can be observed that the ACN percentage decrease in the mobile phase increases Rs,min and tend. However, when pH decreases, Rs,min increases and tend does not change significantly. The chromatographic separation efficiency was optimized by maximizing Rs,min and minimizing tend values which maximized the desirability function over the selected region. The maximum desirability function yielded a tend = 13.6 min and Rs,min = 2.2 at pH 3.6 and 14.5% ACN. The estimated response surfaces predicted that Rs,min > 2 and tend in the range 12.5–15.0 min could be obtained at pH 3.6–3.7 and 13–15% ACN. As a compromise, pH 3.6 and 13% ACN were selected as optimum values. Under these conditions tend = 15.0 min and Rs,min = 2.3 were expected and experimentally assessed. Finally, ammonium formate 5 mM was also tested and selected to avoid problems into the capillary MS nebulizer. |
回复此楼» 猜你喜欢
一志愿厦门大学化学学硕307求调剂
已经有3人回复
-
315分求调剂
已经有4人回复
-
化学调剂一志愿上海交通大学336分-本科上海211
已经有4人回复
-
总分293求调剂
已经有7人回复
-
环境专硕324分求调剂推荐
已经有3人回复
-
284求调剂
已经有3人回复
-
北京林业大学硕导招生广告
已经有6人回复
-
0703化学/290求调剂/本科经历丰富/工科也可
已经有3人回复
-
274求调剂
已经有16人回复
-
一志愿北京化工大学材料与化工（085600）296求调剂
已经有4人回复
» 抢金币啦！回帖就可以得到:
-
祈福中标
+1/226
-
数一英一硕士调剂（双一流高校）
+1/190
-
材料、化学类硕士研究生调剂机会，学硕专硕均可，有意请联系，非诚勿扰！
+1/83
-
青岛大学固态电池研究团队招收材料、化学、物理等方向博士研究生
+2/56
-
【211博士招生】环境化学、地学、毒理方向，擅长污染物迁移转化降解、计算模拟者优先
+1/34
-
招收荧光探针/有机合成/生物学 博士后--薪金: 30万-50万
+1/28
-
春眠不觉晓
+1/20
-
武汉工程大学资源生物技术课题组生物/环境/化工/矿物专业硕士、博士研究生招生及调剂
+1/20
-
中科院物理所二维材料方向招收推免研究生
+1/13
-
双一流湘潭大学化工学院招收化工、能源动力、工程热物理相关研究生调剂
+1/12
-
南昌一本市政工程接受调剂
+1/11
-
大连理工大学气体监测与环境催化团队诚聘副教授、助理教授及博士后3-4名
+1/7
-
双一流天津工业大学电信学院李鸿强教授招收2026年申请审核制博士
+1/5
-
085602调剂
+1/3
-
南医大基础医学院招收调剂生（2生信1生物））
+1/3
-
5科大招收材料专业硕士
+1/3
-
天大福州｜学长推荐上岸新思路
+1/3
-
上海师范大学有机化学专业研究生招生
+1/2
-
上海交通大学环境智能感知实验室招聘博士后
+1/2
-
武汉纺织大学纺织纤维及制品教育部重点实验室招收博士研究生
+1/1
7楼2010-12-07 17:28:31
3楼2010-12-03 18:43:09
5楼2010-12-07 16:12:49
6楼2010-12-07 16:14:54
