Method for Ammonia Determination by Salicylate in Water and TKN Samples, Version 2.0 PRINCIPLE SUMMARY COMPLIANCE

Transcription

1 Methd fr Ammnia Determinatin by Salicylate in Water and TKN Samples, Versin 2.0 PRINCIPLE This methd is designed fr the determinatin f ammnia in water, as well as samples digested by the Ttal Kjedahl Nitrgen (TKN) methd r the Ttal Prtein Methd. The sample is prepared ffline if necessary and then intrduced t the FIAlab analyzer. After injectin, the sample is made alkaline and subsequently intrduced t a gas diffusin cell. Liberated ammnia passes thrugh the membrane f the gas diffusin cell and is absrbed int a stream f hypchlrite. Hypchlrite and sdium salicylate react with ammnia in a tw-step reactin, cnverting it t 5-aminsalicylate. The aminsalicylate is finally xidized in the presence f sdium nitrferricyanide t frm a blue-green clred dye. This methd is designed t be run n the FIAlyzer-FLEX. SUMMARY This methd is designed fr the determinatin f ammnia in water, sil, and ther frms f samples. The methd is capable f detecting ammnia in the range f mg N/L. Fr mre infrmatin, see the sectin n perfrmance metrics. COMPLIANCE This methd fllws EPA Page 1

2 SAFETY The txicity r carcingenicity f all reagents used in this methd must be taken int accunt and therefre each chemical listed belw shuld be handled accrdingly. Each labratry is respnsible fr maintaining cmpliance with OSHA regulatins regarding the safe handling f the chemicals specified in this methd. Material Safety Data Sheets (MSDS) shuld be made available t all persnnel using the methd. All waste materials shuld be dispsed f in a respnsible manner, in accrdance with federal, state, lcal, and any ther applicable regulatins. The fllwing chemicals have the ptential t be highly txic r highly hazardus; fr detailed explanatins cnsult the MSDS: Sdium hydrxide Sdium nitrferricyanide (III) dehydrate Sdium hypchlrite (bleach) EQUIPMENT AND SUPPLIES Equipment: Balance, analytical, with a 0.01 g reslutin Pipettes fr making standards Glassware: Class A vlumetric flask, 1L, QTY 4 Graduated cylinder, 100mL, QTY 1 Plyethylene strage cntainer, 1L, clear, QTY 4 Glass strage cntainer, 1L, brwn tinted, QTY 1 Autsampler (fr high sample lads): Cetac ASX-280/560 (recmmended) r AIM-3200/3300 Page 2

3 REAGENTS AND STANDARDS Chemical part numbers refer t Sigma-Aldrich unless nted therwise. Chemical Chem. Frmula CAS# Supplier PN Deinized Water H 2O Sdium hypchlrite slutin NaOCl (6%) Clrx husehld bleach r equivalent Sdium hydrxide NaOH Sdium salicylate HOC 6H 4COONa S3007 Sdium nitrferricyanide (III) Na 2[Fe(CN) 5NO] 2H 2O dihydrate Diethylenetriaminepentaacetic [(HOOCCH 2) 2NCH 2CH 2] 2NCH 2COOH acid (DTPA) Brij L23 CH 3(CH 2) 10CH 2(OCH 2CH 2) noh Ptassium Sulfate K 2SO Page 3

4 Preparatin f Reagents Carrier: Matrix match carrier t samples. Salt slutin t seawater samples, extractin slutin fr sil samples, etc. Reagent 1: 3M Sdium Hydrxide 50mM DTPA 0.2M K 2SO 4 Slutin (1 L) Disslve 120 g f sdium hydrxide in 800 ml deinized water. Add 15 g DTPA and stir until disslved. Add 35 g ptassium sulfate. Stir until disslved and fill cntainer t 1000mL mark using deinized water. Stre in a plastic cntainer. The slutin shuld appear clrless. Reagent 2: Hypchlrite Slutin (1 L) Mix 60 ml f 6% sdium hypchlrite slutin int 700 ml deinized water. Fill cntainer t the 1 L mark with DI water and stre in a glass bttle. Stre in a plastic cntainer. The slutin shuld appear clrless. Reagent 3: Salicylate Slutin (1 L) Add 150 g f sdium salicylate t 700 ml f deinized water and stir until disslved. Add 0.3 g f sdium nitrferricyanide (III) dihydrate and stir until disslved. Fill cntainer t the 1 L mark with DI water and stre in a glass bttle. Stre in a dark glass cntainer. The slutin shuld appear range-yellw (clr f apple juice). A perceptible red tint indicates a bad slutin. Prbe Wash Slutin: Water with 0.1% Brij L23 (1L) Add 3.3mL Brij L23 t 800mL f deinized water, dilute t 1L. Mix well and stre in a glass bttle. The wash slutin shuld be clear with n particles in it. Ntes n reagent shelf life: Use f high quality labratry glass and plastic bttles is imprtant. Standards shuld be prepared fresh daily. Reagent 1 shuld be prepared every 4 weeks. Reagent 2 shuld be prepared every day. Reagent 3 shuld be prepared every 4 weeks. Preparatin f Standards Dilute 1000 mg/l N-(NH 4) stck slutin with carrier t the desired range f nitrate standards. Page 4

5 SAMPLE COLLECTION AND PRETREATMENT This prtcl nly cvers the analysis prcess. Sample cllectin and pretreatment depends n the type f sample and will have t be determined separately. INSTRUMENT SETUP MID-RANGE Flw injectin analysis apparatus parameters: Cmpnent Specificatins FIAlab PN Analyzer FIAlyzer-1000 r FIAlyzer-FLEX flw injectin analyzer *Inquire Spectrmeter FLAME-T-VIS-NIR Spectrmeter nm Light Surce HL-2000-LL. Tungsten-halgen, nm Peristaltic pump tubing Tygn, 1.02 mm/0.04 in ID (white/white) *Inquire Peristaltic pump tubing Tygn, 0.89 mm/0.03 in ID (range/range) *Inquire Peristaltic pump tubing Tygn, 0.64 mm/0.03 in ID (range/white) *Inquire Peristaltic pump tubing Tygn, 0.51 mm/0.02 in ID (range/yellw) *Inquire Sample injectin lp 35 µl 3.0 in/ 5.7 cm f Tefln capillary tubing with *Inquire 0.03 in/0.75 mm ID Heated reactin cil 1,800 µl 155in/400 cm f Tefln capillary tubing *Inquire with 0.03 in/0.75 mm ID Back pressure cils 20 ft / 600 cm f Tefln capillary tubing with 0.02 in/0.50 mm ID *Inquire Sftware parameters: Parameter Value Pump Speed 100% Primary Spectrmeter Wavelength 660nm Reference Wavelength 570nm Page 5

6 Fig. 1- Flw schematic fr ammnia determinatin. FIASOFT METHOD The prgram script using an autsampler is shwn belw. Fr manual sample intrductin see the FIAsft manual. ' NH4 methd. FIAlab Injectin Valve Sample Lad Delay (sec) 10 Next Sample Delay (sec) 55 Lp Start Autsampler Wash Analyte New Sample Next Sample FIAlab Injectin Valve Sample Inject Delay (sec) 6 FIAlab Injectin Valve Sample Lad Spectrmeter Reference Scan Spectrmeter Absrbance Scanning Delay (sec) 100 Spectrmeter Stp Scanning Lp End Page 6

7 PERFORMANCE METRICS Fig. 2 Example plt and calibratin data fr ammnia. Lwer limit f detectin: 0.50 mg/ L 3.6* 10-6 ml N/ L Lwer limit f quantificatin: mg/l 1.1*10-5 mln/l Upper limit f detectin: mg/l r 3.6*10-6 mln/l 7.1*10-4 mln/l Sample thrughput: 30 samples / hur Startup + Calibratin: 10 minutes Shutdwn: 5 minutes Page 7