技術文章
Technical articles
更新時間:2012-12-07
點擊次數:3238
一、熒光檢測器(qi)(fluorescencedetector,FD)
熒(ying)(ying)(ying)光(guang)(guang)檢(jian)測(ce)(ce)(ce)器(qi)(qi)是一(yi)種高(gao)靈敏(min)度、有選擇性(xing)的(de)(de)(de)檢(jian)測(ce)(ce)(ce)器(qi)(qi),可(ke)檢(jian)測(ce)(ce)(ce)能產生(sheng)熒(ying)(ying)(ying)光(guang)(guang)的(de)(de)(de)化合物(wu)。某些不發熒(ying)(ying)(ying)光(guang)(guang)的(de)(de)(de)物(wu)質可(ke)通過化學衍生(sheng)化生(sheng)成熒(ying)(ying)(ying)光(guang)(guang)衍生(sheng)物(wu),再(zai)進(jin)行熒(ying)(ying)(ying)光(guang)(guang)檢(jian)測(ce)(ce)(ce)。其zui小檢(jian)測(ce)(ce)(ce)濃(nong)度可(ke)達0.1ng/ml,適用于(yu)痕(hen)量分析(xi);一(yi)般(ban)情況下熒(ying)(ying)(ying)光(guang)(guang)檢(jian)測(ce)(ce)(ce)器(qi)(qi)的(de)(de)(de)靈敏(min)度比(bi)紫外檢(jian)測(ce)(ce)(ce)器(qi)(qi)約高(gao)2個數量級,但其線性(xing)范圍不如紫外檢(jian)測(ce)(ce)(ce)器(qi)(qi)寬。近(jin)年來,采用激(ji)光(guang)(guang)作為熒(ying)(ying)(ying)光(guang)(guang)檢(jian)測(ce)(ce)(ce)器(qi)(qi)的(de)(de)(de)光(guang)(guang)源(yuan)而產生(sheng)的(de)(de)(de)激(ji)光(guang)(guang)誘導熒(ying)(ying)(ying)光(guang)(guang)檢(jian)測(ce)(ce)(ce)器(qi)(qi)極(ji)大(da)地(di)增強了熒(ying)(ying)(ying)光(guang)(guang)檢(jian)測(ce)(ce)(ce)的(de)(de)(de)信噪比(bi),因(yin)而具有很高(gao)的(de)(de)(de)靈敏(min)度,在痕(hen)量和(he)超痕(hen)量分析(xi)中得到廣泛應用。
二、示差折光檢(jian)測器(differentialrefractiveIndexdetector,RID)
示差折(zhe)(zhe)光檢(jian)(jian)測(ce)(ce)(ce)器(qi)是一種濃(nong)度(du)型(xing)通用(yong)(yong)檢(jian)(jian)測(ce)(ce)(ce)器(qi),對(dui)所有溶(rong)(rong)質(zhi)(zhi)都有響應,某些不(bu)能用(yong)(yong)選擇性檢(jian)(jian)測(ce)(ce)(ce)器(qi)檢(jian)(jian)測(ce)(ce)(ce)的組分,如高分子化合物、糖類、脂肪烷(wan)烴(jing)等,可用(yong)(yong)示差檢(jian)(jian)測(ce)(ce)(ce)器(qi)檢(jian)(jian)測(ce)(ce)(ce)。示差檢(jian)(jian)測(ce)(ce)(ce)器(qi)是基(ji)于(yu)連續測(ce)(ce)(ce)定樣(yang)(yang)品流路和參比(bi)流路之(zhi)間折(zhe)(zhe)射(she)率(lv)的變化來測(ce)(ce)(ce)定樣(yang)(yang)品含量(liang)的。光從(cong)一種介質(zhi)(zhi)進入另一種介質(zhi)(zhi)時,由于(yu)兩種物質(zhi)(zhi)的折(zhe)(zhe)射(she)率(lv)不(bu)同就會產生折(zhe)(zhe)射(she)。只要樣(yang)(yang)品組分與流動(dong)相(xiang)的折(zhe)(zhe)光指(zhi)數(shu)不(bu)同,就可被檢(jian)(jian)測(ce)(ce)(ce),二者相(xiang)差愈大,靈敏(min)度(du)愈高,在一定濃(nong)度(du)范圍內(nei)檢(jian)(jian)測(ce)(ce)(ce)器(qi)的輸出與溶(rong)(rong)質(zhi)(zhi)濃(nong)度(du)成正(zheng)比(bi)。