Method for Ammonia Determination by Salicylate, Version 2.2

Transcription

1 Methd fr Ammnia Determinatin by Salicylate, Versin 2.2 PRINCIPLE This methd is designed fr the determinatin f ammnia in water, sil, and ther frms f samples. The sample is prepared ffline if necessary and then intrduced t the FIAlab analyzer. In a phenl-free variatin f the Berthelt methd, sdium salicylate reacts with ammnia in a tw-step reactin, cnverting it t 5-aminsalicylate. The aminsalicylate is then xidized in the presence f sdium nitrferricyanide t frm a blue-green clred dye. This methd is designed t be run n the FIAlyzer 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-NH 4 / L. Fr mre infrmatin, see the sectin n perfrmance metrics. 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 Page 1

2 EQUIPMENT AND SUPPLIES Equipment: Balance, analytical, with a 0.01 g reslutin Pipettes fr making standards Glassware: Class A vlumetric flask, 1 L, QTY 2 Graduated cylinder, 100 ml, QTY 1 Glass strage cntainer, 1 L, clear, QTY 1 Glass strage cntainer, 1 L, brwn tinted, QTY 1 Autsampler (fr high sample lads): Cetac ASX-280/560 (recmmended) r AIM-3200/3300 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 (6%) NaOCl Sdium hydrxide NaOH Sdium salicylate HOC 6H 4COONa S3007 Sdium nitrferricyanide (III) (Na 2[Fe(CN) 5NO]*2H 2O) dihydrate Brij L23 Slutin (30%) C 12E B Page 2

3 Preparatin f Reagents Carrier: Matrix match carrier t samples. Salt slutin t seawater samples, extractin slutin fr sil samples, etc. Reagent 1: Hypchlrite Slutin (1 L) Mix 50 ml f sdium hypchlrite (6%) slutin int 700mL f deinized water. Disslve 5 g f sdium hydrxide int this slutin. Add 3 ml f Brij L23 and stir until cmpletely disslved. Fill cntainer t the 1 L mark with DI water and stre in a glass bttle. The reagent shuld be clear with n particles in it. Reagent 2: Salicylate/Catalyst Slutin (1 L) Add 100 g f sdium salicylate t 700mL f DI water and stir until disslved. Add 2.0 g f sdium nitrferricyanide (III) dihydrate and stir until disslved. Add 5.0 g f sdium hydrxide int this slutin and stir until disslved. Add 3 ml f Brij L23 slutin and mix well. Fill cntainer t the 1 L mark with DI water and stre in a glass bttle. Reagent shuld be a light range clr, apprximately the clr f apple juice. Prbe Wash Slutin: Water with 0.1% Brij L23 (1 L) Add 3.3 ml Brij L23 t 800mL f deinized water, dilute t 1 L. Mix well and stre in a plyethylene bttle. The wash slutin shuld be clear with n particles in it. Ntes n reagent shelf life: Use f high quality labratry glass bttles is imprtant. Reagent 1 degrades with time and shuld be prepared daily. Reagent 2 shuld be prepared every week. Preparatin f Standards Dilute 1000 mg/l N-NH 4 / L stck slutin with carrier t the desired range f ammnia standards. 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. Page 3

4 INSTRUMENT SETUP STANDARD 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 1.02 mm ID (white/white) *Inquire Sample Injectin Lp 35 µl 3.0in/7.6cm f Tefln capillary tubing with *Inquire 0.03in/0.71mm ID Reactin cil µl 65in/165cm f Tefln capillary tubing with in/0.76mm ID Reactin cil 2, heated 800 µl in/175cm f Tefln capillary tubing with in/0.75 mm ID heated Waste/backpressure cil 600 µl in/300cm f Tefln capillary tubing with 0.02 in/0.51mm ID SMA-Z Flw Cell 10 mm light path Sftware parameters: Parameter Value Pump Speed 45% Heater 60 C Primary Spectrmeter Wavelength 670nm Secndary Wavelength (ptinal fr extended upper range) 800nm Reference Wavelength 525nm Fig. 1- Flw schematic fr ammnia determinatin. Page 4

5 FIASOFT METHOD The prgram script using an autsampler is shwn belw. Fr manual sample intrductin see the FIAsft manual. FIAlab Injectin Valve Sample Lad FIAlab Peristaltic Pump CunterClckwise(%) 45 Autsampler Wash Next Sample Delay (sec) 60 Lp Start Autsampler Wash Analyte New Sample Next Sample FIAlab Injectin Valve Sample Inject Delay (sec) 3 FIAlab Injectin Valve Sample Lad Spectrmeter Reference Scan Spectrmeter Absrbance Scanning Delay (sec) 30 Spectrmeter Stp Scanning Lp End Autsampler Rinse Delay (sec) 60 Autsampler Wash Delay (sec) 30 Autsave Data C:\Users\FIAlab\Desktp\Autsave Data\DateTime FIAlab Peristaltic Pump Off Page 5

6 PERFORMANCE METRICS Fig. 2 Example calibratin data fr standard ammnia cnfiguratin, primary and secndary wavelengths. Lwer limit f detectin: mgn/l mln/l Upper limit f detectin: 50 mg/l mln/l Sample thrughput: 75 samples / hur Startup + Calibratin: 10 minutes Shutdwn: 5 minutes Page 6

7 ALTERNATE CONFIGURATIONS Lw-Range Setup Cmpnent Specificatins FIAlab PN Sample Injectin Lp 140 µl 12.0in/30.5cm f Tefln capillary tubing with *Inquire 0.03in/0.71mm ID SMA-Z Flw Cell 100 mm light path Fig. 3 Example calibratin data fr lw-range ammnia cnfiguratin, primary wavelength. Lwer limit f detectin: 0.02 mgn/l mln/l Upper limit f detectin: 5 mg/l mln/l Sample thrughput: 75 samples / hur Startup + Calibratin: 10 minutes Shutdwn: 5 minutes Page 7