Direct High-Precision Measurements of the (87)Sr/(86)Sr Isotope Ratio in Natural Water without Chemical Separation Using Thermal Ionization Mass Spectrometry Equipped with 10(12) Ω Resistors.

Thermal ionization mass spectrometry (TIMS) allows excellent precision for determining Sr isotope ratios in natural water samples. Traditionally, a chemical separation procedure using cation exchange resin has been employed to obtain a high purity Sr fraction from natural water, which makes sample preparation time-consuming. In this study, we present a rapid and precise method for the direct determination of the Sr isotope ratio of natural water using TIMS equipped with amplifiers with two 10(12) Ω resistors. To eliminate the (87)Rb isobaric interference, Re ribbons are used as filaments, providing a significant advantage over W ribbons in the inhibition of Rb(+) emission, based on systematically examining a series of NIST SRM987 standard doping with various amounts of Rb using Re and W ribbons. To validate the applicability of our method, twenty-two natural water samples, including different water types (rain, snow, river, lake and drinking water), that show a large range in Sr content variations (2.54-922.8 ppb), were collected and analyzed from North and South China. Analytical results show good precision (0.003-0.005%, 2 RSE) and the method was further validated by comparative analysis of the same water with and without chemical separation. The method is simple and rapid, eliminates sample preparation time, and prevents potential contamination during complicated sample-preparation procedures. Therefore, a high sample throughput inherent to the TIMS can be fully utilized.

[1]  L. Heaman,et al.  Precise Pb isotope ratio determination of picogram-size samples: A comparison between multiple Faraday collectors equipped with 1012 Ω amplifiers and multiple ion counters , 2015 .

[2]  E. Hegner,et al.  High-precision (143)Nd/(144)Nd ratios from NdO(+) data corrected with in-run measured oxygen isotope ratios. , 2014, Analytical chemistry.

[3]  J. Koornneef,et al.  Measurement of small ion beams by thermal ionisation mass spectrometry using new 10(13) Ohm resistors. , 2014, Analytica chimica acta.

[4]  J. Koornneef,et al.  Use of 1012 ohm current amplifiers in Sr and Nd isotope analyses by TIMS for application to sub-nanogram samples , 2013 .

[5]  Yue-heng Yang,et al.  Rapid and precise determination of Sr and Nd isotopic ratios in geological samples from the same filament loading by thermal ionization mass spectrometry employing a single-step separation scheme. , 2012, Analytica chimica acta.

[6]  A. Makishima,et al.  High-resolution MC-ICPMS employing amplifiers with a 1012 ohm resistor for bulk sulfur determination in biological and geological samples , 2012 .

[7]  Yue-heng Yang,et al.  High-precision direct determination of the 87Sr/86Sr isotope ratio of bottled Sr-rich natural mineral drinking water using multiple collector inductively coupled plasma mass spectrometry , 2011 .

[8]  Yangting Lin,et al.  Rb‐Sr and Sm‐Nd isotopic systematics of the lherzolitic shergottite GRV 99027 , 2011 .

[9]  A. Makishima,et al.  Precise isotopic determination of Hf and Pb at sub-nano gram levels by MC-ICP-MS employing a newly designed sample cone and a pre-amplifier with a 1012 ohm register , 2010 .

[10]  Yue-heng Yang,et al.  Combined chemical separation of Lu, Hf, Rb, Sr, Sm and Nd from a single rock digest and precise and accurate isotope determinations of Lu–Hf, Rb–Sr and Sm–Nd isotope systems using Multi-Collector ICP-MS and TIMS , 2010 .

[11]  A. Love,et al.  Sr isotopes in natural waters: Applications to source characterisation and water–rock interaction in contrasting landscapes , 2009 .

[12]  C. Brach-Papa,et al.  Fit for purpose validated method for the determination of the strontium isotopic signature in mineral water samples by multi-collector inductively coupled plasma mass spectrometry , 2009 .

[13]  C. Ottley,et al.  Methods for the microsampling and high-precision analysis of strontium and rubidium isotopes at single crystal scale for petrological and geochronological applications , 2006 .

[14]  Qiu-li Li,et al.  Ultra-low procedural blank and the single-grain mica Rb-Sr isochron dating , 2005 .

[15]  M. Wieser,et al.  The development of multiple collector mass spectrometry for isotope ratio measurements , 2005 .

[16]  C. Frost,et al.  Strontium Isotopic Identification of Water‐Rock Interaction and Ground Water Mixing , 2004, Ground water.

[17]  I. Gavrieli,et al.  Direct high-precision measurements of the 87Sr/86Sr isotope ratio in natural water, carbonates and related materials by multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) , 2001 .

[18]  C. Deniel,et al.  Single-stage method for the simultaneous isolation of lead and strontium from silicate samples for isotopic measurements , 2001 .

[19]  Jean-Luc Probst,et al.  Strontium isotope compositions of river waters as records of lithology-dependent mass transfers: the Garonne river and its tributaries (SW France) , 2000 .

[20]  N. Nakamura,et al.  Separation of rare earth elements and strontium from chondritic meteorites by miniaturized extraction chromatography for elemental and isotopic analyses , 2000 .

[21]  J. Edmond,et al.  Controls over the strontium isotope composition of river water , 1992 .