用于定量色度和浊度测量的紫外可见分光光度计

通过向测试溶液中加入腐殖酸，观察390 nm处的吸收，显示酸的黄色，来检查清水和废水的着色度。浊度描述了由于清水和废水中的不溶性颗粒、微生物和有机物而造成的溶液的相对清晰度。浊度可以通过透射测量法中的紫外/可见分光光度计或积分球从溶液中材料散射的光量来测量。Application Note Using a UV-Visible Spectrophotometer to ObtainQuantitative Chromaticity and Turbidity Measurements2/4Application Note Using a UV-Visible Spectrophotometer to Obtain Quantitative Chromaticity and Turbidity Measurements Intro d uc t ion Chromaticity measu r ements a r e used to c h eck the coloration degree of clean water and waste water by adding hum i c ac i d to the test solution and observi n g the absorpt i o n at 390 n m whic h shows the yellow color of the acid. The turbidity describes the re l ative clarity of a solut i on due to inso l uble pa r ticles， microbe and organic s u bstance in clean water and waste wate r . The degree of turbidity can be measured by the amou n t of light scattered from the mate r ials in the solution using a UV/Vis spectrophotometer i n transmission measu r ement method or an i n teg r ating sphe r e. V-630 This application n ote descr i bes quantitat i ve c h romatici t y and turbidity measu r ements using a UV/Vis spectrophotometer based on t he clea n water test method. UV-Visible Spectro p hotomete r K ey words V -630/650/660/670，U V-Vi sible/N IR ， Mat e r ia l s ， C h r o mati city， T u rbi d it y ， L S E-701 Lo n g p a th l en gth c el l h o lde r， VWWQ-789Ch r om at i c i ty /tu rbi d ity m easure me n t prog ram， I SV -722/I SN N-723 I n t eg ratin g s phe r e Chromaticity Measurements Cobalt chlo r opla ti nate has a color simi l a r to the yellow-brown of h umin and is used as a standard sample for the ch r oma t icity measurements. 2.49 g of potassium ch l oroplat i nate and 2.02 g of cobalt c h loride are d i ssolved i n 200 mL of hydroc h loric acid. Puri fi ed wa t er i s then add e d to th e solu ti on to make a total volume of 1 L . T h is solution is t he neat sta n dard sample with a c h romatici t y of 1000 degr e e . T h e standard sol u tions us e d to create the absorbance calibration cu r ve a r e prepa r ed fr o m t h e neat standard s ample and diluted wi th purif i ed water . Both the blank and water samples are f i ltering using a 0.2 um membra n e fil t er . Wa t er samples c a n al s o b e centri f uged with the supernatant used as the sample. The absorption of the standard solutions at 390 nm were measured using a 50 mm pathlength cel l . The calibration curve is shown i n Figure 1 and the co r responding values and ca l culated chromaticity results are shown i n Table 1. Figure 1. Chroma t i ci t y c a lib r a t ion c ur ve . Table 1. Chr o m a t icit y c a libra tio n c u r ve r esults . Concentration (Chromaticity) Absorbance Calculated Chromaticity 0 0.000 -0.06 0.5 0.004 0.51 1 0.007 0.97 2 0.015 2.04 20 0.141 20.07 50 0.350 49.99 100 0.699 99.99 From the above r e sult s ， the standa r d deviat i o n (o) between th e obtain e d quan ti tative va lu e a n d actu a l chromat i city is 0.04(6) d e gree， the d e tec t ion limit is 0.15， a n d th e quant i tation limit is 0.46 d egre e . The detec t ion l i m it i s calcu l a t ed fr om 3.3o while t he quant it ative limit i s ca l c u lated from 10o. Turbidity Measurements An imm i xture p o l ystrene n e suspens i o n is u s ed a s the st a ndard sample f or th e t u rbidity measurements. 5 n eat solutions of p olystyr e ne par t i c l es wi t h a t u rbidity at 100 are shown i n Ta b le 2 along wit h their corresponding m ix in g r atios and d i ameters. To cr e a t e th e cal ib ratio n cu r ve ， th e n eat sample solu ti o n s are dilu t ed with puri f i ed water at 0， 5， 10， 50，and 100 degr ee s a n d mea s ur e d in t r ansm i ssion mod e u sin g a 20 m m p a th l en gth ce ll . Purif i ed water f i l ter e d usi n g a 0.2 um mem b ran e i s u se d as th e blank solut i on . T h e calibrat i on curve and corr e spondi n g results ar e shown in Figur e 2 and Ta b le 3. T h e sta n da r d d e v i at i on i s also calculat e d as 0.36 d e gr ee， the d e t e c t io n l imit as 1.18， and t h e quant i tat i o n li m i t as 3.6d egrees. JASCO INC. 28600 Mary's Cour t ， E a s to n ， M D 21601US A Figure 2. Tur bid ity c al i bra tio n c u r ve. Table 2. Turb idi ty c a l ib r at ion c ur v e re s ul ts . Concentration (Turbidity) Absorbance Calculated Chromaticity 0 0.000 -0.27 5 0.026 4.81 10 0.052 10.07 20 0.102 20.09 50 0.256 50.64 100 0.502 99.67 The blank a n d sta n dard solut i ons we re t h en dilut e d i n pu r if ie d wat e r to the fi n al conc e n tr ations l i st e d i n Tabl e 4 and m e asur e d us i ng a 20 m m pat h le n gth cell and an int e gra t i n g spher e to obtai n the d i ffuse transmittance . A sta n dard whit e d iff user plate was f i r st mounted i n the integrating sphere a n d the total ligh t (T，) at 660 n m was measured. The plate was the n removed and the dif f use t ransmittance (T ) of t h e sample can the n be measured . Figure 3. Diffus e t r a n smit t a n c e me as ur e men t u si n g t h e i n t e grati ng sph ere. 28600 Mary's Cour t ， E a s to n ， M D 21601US A The turbidity is calculated from the dif f use transmittance results and are shown in Table 4， along with the cal i bration cu r ve shown in Figu r e 4. The standard deviat i on is calculated as 0.08 degree， the detec ti on l i m i t as 0.28， and the quantitat i on limit as 0.86 degree. A 50 mm l i ght path l ength rectangular cell is recommend to be u sed f or the analysis of low turbidity samples wi t h concentrat i ons close to or l ess than the qua n titation limit. Figure 4. T u rb idity c ali b ra t ion c urve from di f fu s e trans mi t tance m e a s ur em en ts . Table 4. T ur b id i t y c a li b r a tion c ur v e res ul t s. Concentration (Turbidity) T/Tx100 Quantitative Value (Turbidity) 0 0.004 -0.05 0.5 0.389 0.50 1 0.726 0.98 2 1.435 1.99 5 3.666 5.17 10 7.003 9.92 JASCO INC. 28600 Mary's Cour t ， E a s to n ， M D 21601US A A ppli c a tio n Lib r ary： htt p：//www.jas co in c .c o m/a pp l icatio n s