Analytical Methods

Summary of Methods Used and Detection Limits

The following table gives a brief description of the methods used to conduct the analyses. The detection limits given below are those attainable in a relatively clean matrix. Detection limits may be higher for individual samples should insufficient sample be available, or if the matrix requires that dilutions be performed during analysis.

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PARAMETER METHOD USED DETECTION LIMIT
Alkalinity (as HCO3) Auto titration method
APHA 2320 - B 22nd Edition 2012
5 mg/L
Aluminium ICP-OES
APHA 3120-B 22nd Edition 2012
0.02 mg/L
Ammonia (total as NH3) Flow Injection Analyser
APHA 4500 NH3-H 22nd Edition 2012
0.003 mg/L
Ammonia (as NH3) Flow Injection Analyser
APHA 4500 NH3-H 22nd Edition 2012
0.003 mg/L
Arsenic ICP-OES
APHA 3120-B 22nd Edition 2012
0.01 mg/L
Barium ICP-OES
APHA 3120-B 22nd Edition 2012
0.001 mg/L
Benzoate Ion Chromatography
Dionex Application Note 165 – Column AS18
0.05 mg/L
Bicarbonate (total) HCO3 Titration Method
ASTM Standards D513-82 Vol.11.01 of 1988
20 mg/L
Boron ICP-OES
APHA 3120-B 22nd Edition 2012
0.2 mg/L
Boron (groundwater) ICP-OES
APHA 3120-B 22nd Edition 2012
0.1 mg/L
Bromide Ion Chromatography
APHA 4110-B 22nd Edition 2012
0.02 mg/L
Calcium ICP-OES
APHA 3120-B 22nd Edition 2012
0.01 mg/L
Caesium Atomic Absorption Spectrometry
APHA 3500-Cs 22nd Edition 2012
0.02 mg/L
Chloride Ion Chromatography
APHA 4110-B 22nd Edition 2012
0.05 mg/L
Chloride in condensate Ion Chromatography
APHA 4110-B 22nd Edition 2012
0.01 mg/L
Chloride Potentiometric Method
APHA 4500-Cl D 22nd Edition 2012
20 mg/L
Conductivity Conductivity Meter
APHA 2510 B 22nd Edition 2012
1.0 µS/cm
Copper ICP-OES
APHA 3120-B 22nd Edition 2012
0.001 mg/L
Fluoride Ion Selective Electrode
APHA 4500-F C 22nd Edition 2012
0.03 mg/L
Fluoride Ion Chromatography
APHA 4110-B 22nd Edition 2012
0.02 mg/L
Iron ICP-OES
APHA 3120-B22nd Edition 2012
0.01 mg/L
Lithium ICP-OES
APHA 3120-B 22nd Edition 2012
0.01 mg/L
Magnesium ICP-OES
APHA 3120-B 22nd Edition 2012
0.01 mg/L
Manganese ICP-OES
APHA 3120-B 22nd Edition 2012
0.005 mg/L
Nitrate Nitrogen
(as N)
Flow Injection Analyser
QuickChem 8500 Series 2 Method
0.002 mg/L
Nitrite Nitrogen
(as N)
Flow Injection Analyser
QuickChem 8500 Series 2 Method
0.002 mg/L
NDS Tracers HPLC - Fluorescence detection
Rose et al, 2001, 2002
0.04 ppb
NSA Tracers HPLC - Fluorescence detection
Rose et al, 2001, 2002
0.03 ppb
pH Electrometric Method
APHA 4500-H+ B 22nd Edition 2012
-
Phosphorus
(Dissolved reactive)
Flow Injection Analyser
APHA 4500-P G (modified) 22nd Edition 2012
0.002 mg/l
Potassium (geothermal) ICP-OES
APHA 3120-B 22nd Edition 2012
0.35 mg/L
Potassium (groundwater) ICP-OES
APHA 3120-B 22nd Edition 2012
0.11 mg/L
Rubidium Atomic Absorption Spectrometry
APHA 3500-Rb 22nd Edition 2012
0.01 mg/L
Silica (geothermal, SiO2) ICP-OES
APHA 3120-B 22nd Edition 2012
0.1 mg/L
Silica (groundwater, SiO2) ICP-OES
APHA 3120-B 22nd Edition 2012
0.05 mg/L
Silica (as SiO2)
(Monomeric)
Molybdosilicate colourimetric method
APHA 4500-SiO2 C 22nd Edition 2012
0.05 mg/L
SiO2 in condensate ICP-OES
Alpha 3120-B 22nd Edition 2012
0.01 mg/L
Silica (HF treated) ICP-OES
Alpha 3120-B 22nd Edition 2012
0.1 mg/L
Sodium (geothermal) ICP-OES
APHA 3120-B 22nd Edition 2012
1.0 mg/L
Sodium (groundwater) ICP-OES
APHA 3120-B 22nd Edition 2012
0.02 mg/L
Sodium (low level) Atomic Absorption Spectrometry
APHA 3500-Na B 22nd Edition 2012
0.005 mg/L
Strontium ICP-OES
APHA 3120-B 22nd Edition 2012
0.001 mg/L
Sulphide
(total as H2S)
Iodometric Method
APHA 4500-S2 F 22nd Edition 2012
0.2 mg/L
Sulphide
(total as H2S)
Flow Injection Analyser
APHA 4500-S2 D 22nd Edition 2012
0.01 mg/L
Sulphate Ion Chromatography
APHA 4110-B 22nd Edition 2012
0.03 mg/L
Sulphate in condensate Ion Chromatography
APHA 4110-B 22nd Edition 2012
0.04 mg/L
Sulphur total
(as SO4)
ICP-OES
APHA 3120-B 22nd Edition 2012
0.45 mg/L
Suspended Solids
(1L sample)
Filtration – (0.45um)
APHA 2 450-D 22nd Edition 2012
0.3 mg/L
Total dissolved solids By calculation  
He TCD Gas Chromatography
Giggenbach and Goguel, 1989
 
H2 TCD Gas Chromatography
Giggenbach and Goguel, 1989
 
O2 TCD Gas Chromatography
Giggenbach and Goguel, 1989
 
N2 TCD Gas Chromatography
Giggenbach and Goguel, 1989
 
CH4 FID Gas Chromatography
Giggenbach and Goguel, 1989
 
Ar TCD Gas Chromatography
Giggenbach and Goguel, 1989
 
C2 – C5 FID Gas Chromatography  
SF6 ECD Gas Chromatography  
References for standard methods
ICP-OES APHA 3120-B 22nd Edition 2012
ICP-MS APHA 3125-B 22nd Edition 2012
Potentiometric APHA 4500-Cl-D 22nd Edition 2012
Ion Chromatography APHA 4110-B 22nd Edition 2012
ISE APHA 4500-F-C 22nd Edition 2012
δ2H Donnelly et al, 2001
δ18O Epstein and Mayeda, 1953
Gases Giggenbach and Goguel, 1988
NDS & NSA Tracers Rose et al, 2001; Rose et al, 2002
  • APHA 22nd Edition 2012 is the American Public Health Administration Volume on standard methods of water analysis.
  • Donnelly, T., S. Waldron, A. Tait, J. Dougans, and S. Bearhop, 2001: Hydrogen isotope analysis of natural abundance and deterium-enriched waters by reduction over chromium on-line to a dynamic dual inlet isotope-ratio mass spectrometer. Rapid Communications in Mass Spectrometry, 15, 1297-1303.
  • Epstein, S. and T. Mayeda, 1953: Variation of 18O content of waters from natural sources. Geochimica et Cosmochimica Acta, 4, 213-224.
  • Giggenbach, W. and Goguel, 1989: Collection and Analysis of Geothermal and Volcanic Waters and Gas Discharges. Report No. CD2401, Chemistry Division, Department of Scientific and Industrial Research, Petone, New Zealand.
  • Rose, P.E., Benoit, W.R., Kilbourn, P.M. 2001. The application of the polyaromatic sulfonates as tracers in geothermal reservoirs. Geothermics, 30, 617-640.
  • Rose, P.E., Johnson, S.D., Kilbourn, P. Kasteler, C. 2002. Tracer testing at Dixie Valley, Nevada using 1-naphthalene sulphonate and 2,6-naphthalene disulphonate. In Proceedings Stanford Workshop on Geothermal Reservoir Engineering, Stanford University, California, January 28-30. 6p.

Accreditation

  • The New Zealand Geothermal Analytical Laboratory received International Accreditation New Zealand (IANZ) accreditation in 2000 for the analysis of non-potable (groundwaters) and geothermal waters. The laboratory has been accredited by IANZ for geothermal/volcanic gas analyses (in 2007). This accreditation, covering staff training, quality control, methodology and management, is compliant with NZS/ISO/IEC 17025:2005. Our laboratory is audited annually by IANZ.
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