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1 w y wz 9«( 3y) 199~206, 2006 J. of the Korean Society for Environmental Analysis sƒ(i) ½» *Áx Á * w yw w, w y œw Evaluation of Manual and Automated Methods in Total Nitrogen (TN) and Total Phosphorus (TP) Analysis (I) TN Analysis Kee Dong Kim*, Mi-Kyung Heo, and Yong-Chan Seo *Department of Fine Chemical and Advanced Materials, Sangji University, 660 Usan-dong, Wonju, Korea Department of Environmental Engineering, Sangji University, 660 Usan-dong, Wonju, Korea Automated instrumental analyses are introduced for the determination of total nitrogen (TN) and total phosphorus (TP) in water. Since the automatized analysis provide very reliable data with less labor and chemicals, it is considered as a replaceable technic for substituting the currently available manual method. Actually, this automated technic has been practically used for the determination TN and TP in compliance with water quality monitoring regulation in Korea. Automated method is also adapting the same operating principle of manual analysis which is approved by Ministry of Environment of Korea. Segmented flow analysis (SFA) system was applied for automated technic for the simultaneous determination of TN and TP. TN concentration data obtained by both manual and automated techniques are evaluated for the mutual comparability. Method detection level (MDL), precision, accuracy, interferences, etc. values were compared, either directly or after statistical treatment, to test equivalency between two methods. Automated method turned out to be at least equivalent or better than manual method in TN determination of relatively clean water sample. One of the main restrictions in broadening the application of automated method is found to be its narrow range of detection in analyzing water sample espcially ones containing high concentrated suspended solid. Particulate matters in water samples interfere the determination of TN concentration negatively, in general. Key words : total nitrogen (TN), total phosphorus (TP), segmented flow analysis (SFA), automated analysis 1. œ» ƒ w yw l w»¾, ƒ w l w ¾ w š ¾ ƒ š ywš.»» w.» (Albuminoid), (C 5 H 4 N 4 O 3 ).»,, ƒ. š k» w w. t» w. t w w ùkù» w. w 10 mg NO 3 -N/L wwš. w» yw To whom correspondence should be addressed.

2 200 ½» Áx Á w wù w w. y w». ³ w yw yw y y., w y w y w» w w tƒ. t s w. w û ùkü, m m». 1~3) œ x w d w» w»» ww z, w. ww w š, ƒƒ w. ù œ x w k. ù,,» w wš. ù ¾. y w š k». œ w, l w w œ w e ü w. 4) y (Flow Injection analysis, FIA) 5,6) (Segmented Flow Analysis, SFA) 6-8) ƒ ù. x x ƒ r SFA w w. SFA w k (validation) sƒ w» w (method detection, level, MDL), x, spike recovery m w y, w, w matrix w ƒ xw ,9,10)» w w, s, s, w, s, 2 L w 4C þ o w. y x w» w s, w Whatman GF/C 4 mm Ø w z 3 z x w, t 2 mg/l, t 5 mg/l w y xw (Table 1).»»ƒ ù w y w» w, Amonium Chloride (NH 4 Cl), EDTA (C 10 H 14 N 2 Na 2 O 8 2H 2 O), L-Glutamic acid (HOOC (CH 2 ) 2 CH(NH 2 )COOH) ƒ yw 2 mg N/L 5 mg N/L w. w» w ƒ (Fe) (Cu) yw w. œ x w w. t (1, 5 mg NO 3 -N/L) (250, 500, 1000, 2500, 5000, 10000, mg/l) ƒw w y w. 2.2.»»» ( ŸŸ ) Ÿ Varian Carry 50 UV Spectrophotometer 220 nm d w. Autoclave 120 C o Table 1. Sample specifications for the analysis of TN and TP No Sample Samplind date Sampling Station 1 Stream Water Nak Dong river, Won Ju Jusan bridge 2 Textile Wastewater (Effluent) Su Won Banwol Plants 3 Saline Wastewater (Effluent) Won Ju Kim-chi Plant 4 POTW * Effluent Won Ju Municipal Effluent 5 Livestock Wastewater Won Ju Hyantogyebal 6 POTW (Inffluent, Effluent) Nak Dong river * Publicly owned treatment works

3 sƒ(i) ƒ w w w 100 ml ü ü w »» (ep y ) 11) BRAN-RUEBBE AACS w»» Table 2 w. y»» w (TN) Diagram, ƒ w. Table 2. Analitical condition of automatic analysis system Instrument Part Digester temperature TN Heating block temperature Air Compressor Pressure : Main Gage (for digester) Homogenizer time Micro Wave (TN) 2.3. p w ( ŸŸ ) Condition 110 o C TN(40 o C) 0.29 Mpa 0.13 Mpa 20 sec 550 nm Fig. 1. A schematic diagram for the analysis of total nitrogen (TN). (TN) a) e y e : 500 ml yùp (NaOH;, x w % w ) 15 g y e (Potassium Persulfate, K 2 S 2 O 8 ;, x w % w ) 15 g. w w. b) (1+16) : 160 ml w (c-hcl) 10 ml yww »» (e y ) (TNTP) a) e y e (Alkaline peroxodisulfate) : y e (Potassium Persulfate, K 2 S 2 O 8 ;, x w % w ) 12.5 g, (Boric acid) 5.0 g, yùp (NaCl) 0.5 g, y ùp (Na 2 SO 4 ) 0.5 g 500 ml z 2.0 ml 5 N- NaOH š 500 ml ƒ. v ph 8 b) y : 100 ml z y 16 ml š 200 ml. (TN) a) (imidazole) : 30 g 800 ml z y (H 2 SO 4 ) 4 ml ƒw ml¾ z 1 ml 50% triton-x š. b) NED color : NED (N-1-Nap-hthylethylenediamine 2HCl) 0.5 g, (HCl) 5 ml z 500 ml. c) Sulfanilamaide : r (Sulfanilamaide) 5 g, (HCl) 50 ml 500 ml w (TN) t ( ŸŸ ) t (100 mg NO 3 -N/L) : C 4 w e o (KNO 3 ; t ) g y 1000 ml w. t (100 mg NO 3 -N/L) 10 w w z (1+500) 2 ml š w.

4 202 ½» Áx Á »» (Segmented Flow Analysis, SFA) t (1000 mg NO 3 -N /L) : C 4 w e o (KNO 3 ; t ) g y 100 ml w. t (1000 mg NO 3 -N/ L) 20 ml 100 ml w t 200 mg NO 3 -N/L w. yw t 1.25, 2.5, 5 ml w 100 ml w š w. 3. š ,13) š t ƒƒ 0~10 mg NO 3 -N/L w w. Table 3 ( ŸŸ ) r 2 = š,»» r 2 = ù ŸŸ w»» 6 mg NO 3 -N/L Ÿ ƒ 1. Lambert-beer e w Ÿ 1 w, 5 mg NO 3 -N/L w š w w (MDL) t 0.2 mg NO 3 -N/L w 7 œ x»» (SFA) w. š ƒƒ t r 3.14( 95% t ) w w (MDL) w. œ x w 0.12 mg/l š,»» (SFA) w 0.02 mg/l û w (MDL) x ü w kw w. Û10%. ( ŸŸ )»» Table 4 Û10%. œ x»» û t r (RPD, %) ùkü x. RPDƒ 10% w w ƒ ù Table 3. Precision data š q. Manual Automated Linearity r 2 = r 2 = M.D.L mg/l 0.02 mg/l Duplicate % (Ave. 9.08%) % (Ave. 2.12%) Table 4. Results of replicate analysis of TN data Sample Stream Water Livestock Wastewater Wastewater Treatment Area Saline Wastewater Sample ID A B C D E F G H I Method Sample Concentration (mg/l) Duplicate Concentration (mg/l) % RPD Automated Manual Automated Manual Automated Manual Automated Manual Automated Manual Automated Manual Automated Manual Automated Manual Automated Manual z (Recovery) z (Recovery, %)» w» t ƒw w % ü w w t w ƒƒ (0.5, 1, 2, 5, 100, 300, 500 mg/l) (0.5, 1, 2, 5, 10, 50, 100, 300, 500 mg/l) y, ƒw z., t 2 mg NO 3 -N/L w wƒ ù ƒ û wƒ.

5 sƒ(i) 203 Table 5. Interference of total nitrogen analysis induced by copper and iron (spiked concentration, 2 mg N/L) Interfer ence Copper (Cu) Iron (Fe) Concentration (mg/l) Automated Mesured (mg/l) % Mesured Recovery (mg/l) Manual % Recovery w w t 1 mg NO 3 -N/L 5 mg NO 3 -N/L ƒƒ 7 w (250, 500, 1000, 2500, 5000, 10000, mg/l)w d w. positive error ùkü ƒ, ƒ û j w y w.»» w œ x w ƒ w. 3.2.»» (SFA) p 14) Table 8»»» w Table 6. Interference of total nitrogen analysis induced by chloride (spiked concentration, 1 mg N/L) Unit : mg/l Cl - Manual RPD (%) Automated RPD (%) Table 7. Interference of chloride an total nitrogen analysis (spiked concentration, 5 mg N/L) Unit : mg/l Cl - Manual RPD (%) Automated RPD (%) t 5 mg/l 10z w t r wš 95.5% t 2σ w š, 99.7% t 3σ w w w. 13 t d w»» y w. ƒ ( w ƒ û ) (CV%)ƒ 3% w w.»» y» w w. t 5 mg/l w 10z d w,»» 99.9% w w. Table 8. Reproducibility of verification sample analysis Frequency TN (5 mg N/L) Average SD CV(%) »» y q w» w Amonium Chloride (NH 4 Cl), EDTA (C 10 H 14 N 2 Na 2 O 8 2H 2 O), L-Glutamic acid (HOOC(CH 2 ) 2 CH(NH 2 )COOH) œ ƒw ƒƒ 2 mg N/L 5 mg N/Lƒ w w. Table 9

6 204 ½» Áx Á % z ùkü»» w š. Table 9. Recovery of total nitrogen Mean Recovery % Compound 2 mg N/L 5 mg N/L Amonium Chloride EDTA L-Glutamic acid ƒƒ w, š s w ( ŸŸ )»» d w w. x ƒ š w» w t x ww. 95% w w t Student t w y w. Fig. 2. Comparison between Manual and Automated Analyses of Stream Water (TN) r 2 = y w. s³ w ùküš. t = d ---- n s d d d i ( )2 s d = n 1 w 63 w l t š 95% Student t w ùkû. ù s³ w ùküš, w w q. w w 9 w 54 w t š 95% Student t y w, w t(fig. 2) r 2 = y w. (, ) 7 w t š 95% Student t w y. w t (Fig. 3) Fig. 3. Comparison between Manual and Automated Analyses of Wastewater Treatment Area (TN). s 5 w t š 95% Student t w y. w t (Fig. 4) r 2 = y ù Áòw w. s³ w ùküš. ù

7 sƒ(i) 205 ƒ k m yw w. Fig. 4. Comparison between Manual and Automated Analyses of Livestock Wastewater (TN) t ƒƒ 0-10 mg NO 3 -N/L yw w r 2 = š,»» r 2 = š. w (MDL) œ x w 0.12 mg/l š,»» (SFA) w 0.02 mg/l û w., x Û10 % w ù œ x»» û t r (RPD, %) ùkü»» x q. RPD (%)ƒ 10% w w ƒ ù š q. w z (Recovery, %) ƒ % ü. w w w w wƒ ù ƒ û wƒ. w ùkû,»» w œ x w ƒ w. 4.2.»» (SFA) z x z t 5 mg/l 10z w»» (CV%) 3% w w š 99.9% š. ù ƒ w. Amonium Chloride (NH 4 Cl), EDTA (C 10 H 14 N 2 Na 2 O 8 2H 2 O), L-Glutamic acid (HOOC(CH 2 ) 2 CH(NH 2 ) COOH) ƒƒ 2 mg N/L 5 mg N/L w»» œ w z x %»» d š ƒƒ w, š s w ( ŸŸ )»» d w w w (, ) x w w w eƒ ù s ƒ ùkùš. ù s ƒ e w». xk y ù,»» p w yw ùkü. wš t x w 95% w w š. w š, w ƒ š w. w wš» d w ù, p x w ƒ»w w q w.

8 206 ½» Áx Á š x 1. ½ k, œ x w, Ÿ q, Standard Method, Nitrogen, 4500-N A. 3. ½, y, y, y yw,», 2000, p Gray D. Christian,, w,, q», w œ, yw,, 1996, p ½k,, Flow Injection Analysis (FIA), w w» yw, Vol. 1, No 2, Ÿv, {, Ÿ, Flow Injection Analysis, w t w», Vol. No 2, Standard Method, Segmented Continuous Flow Analysis, 4120 A. 8. Standard Method, Inorganic Nonmetals by Flow Injection Analysis, 4130 A. 9. Standard Method, Quality Assurance/Quality Control, 4130 A, 4130 B. 10. Standard Method, Nitrogen, 4500-N B. 11. U. S. EPA, Nitrogen, Nitrate-Nitrite (Colorimetric, Automated, Cadmium Reduction), Method , Auto Analyzer w w (2), e w j e g, eƒ f e, yw x d Auto Analyzer y (œ x w z ), ( ) i p l», Daniel C. Harris, ½, ½w,,, yw 5th. ed. e, p