Simultaneous determination of 226Ra, 228Ra and 210Pb in drinking water using 3M Empore™ RAD disk by LSC-PLS

Recent progresses in analytical method development for 210Pb in environmental and biological samples

As a decay product of uranium series, 210Pb spreads widely in the nature and imposes strong radiological and chemical toxicity. It is vital to establish reliable and efficient radioanalytical methods for 210Pb determination to support environment and food radioactivity monitoring programs. This article critically reviews analytical methods developed for determining 210Pb in environmental and biological samples, especially new development in recent years. Techniques applied throughout different analytical steps including sample pretreatment, separation, purification, and detection are summarized and their pros and cons are discussed to provide a holistic overview for 210Pb environmental and biological assay.

Simultaneous determination of 210Pb and 90Sr and 210Po isolation in sludge samples using a plastic scintillation resin

This study describes a new and fast method for separating ²¹⁰Po from ²¹⁰Pb and ⁹⁰Sr, before simultaneously measuring the individual activities of the latter two radionuclides using a plastic scintillation resin (PSresin) in sludge samples taken from a drinking water treatment plant. This method speeds up the analysis process significantly by simultaneously measuring ²¹⁰Pb and ⁹⁰Sr in a single step. The method is reproducible and has a relative standard deviation of less than 25% for ²¹⁰Pb, ²¹⁰Po and ⁹⁰Sr. The method was satisfactorily validated with an intercomparison sample and applied to sludge samples from a drinking water treatment plant. The minimum detectable activities for 0.9 g of sludge are 5.5 Bq/kg and 8 Bq/kg for ²¹⁰Pb and ⁹⁰Sr respectively when measured for 180 min, and 0.5 Bq/kg for ²¹⁰Po when measured for 5000 min.

DECLAB: a software for liquid scintillation spectra deconvolution

The deconvolution of liquid scintillation (LS) spectra is meaningful in several scenarios like supporting incomplete radiochemical separations, for screening purposes and determining different isotopes of the same element, which is explored in this paper for the case of 89Sr/90Sr. In this paper DECLAB, an online application for liquid scintillation spectra analysis is presented. The software considers the classical calibration modes like constant efficiency and quenching curve and furthermore, the deconvolution of multicomponent spectra by means of Partial Least Square Regression. DECLAB is designed to analyse Perkin Elmer Wallac Quantulus 1220 spectra. However, in further upgrades, the applicability of this tool will be extended to other LS spectrometers.

Scintillating and wavelength shifting effect investigation of 3-methylpiridinium salicylate and its application in LSC measurements

Possible application of a novel ionic liquid 3-methylpiridinium salicylate (3-MPS) in Liquid Scintillation Counting measurements has been explored. Its addition to several radionuclides' aqueous solutions shown a significant influence on ²¹⁰Pb Cherenkov spectra, ²¹⁰Pb and ²²⁶Ra gross alpha/beta spectra, even on ³H spectra appearance. 3-MPS manifested both wavelength shifting and scintillating effect, indicating that 3-MPS or other ionic liquids of similar structure soon might be implemented into the common LSC practise as an alternative to the commercial LSC cocktails.

A new rapid protocol for 226Ra separation and preconcentration in natural water samples using molecular recognition technology for ICP-MS analysis

A new rapid protocol for ²²⁶Ra separation and preconcentration in natural water samples was developed before its determination by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). For this purpose, the commercially available Ra specific resin AnaLig^® Ra-01 was used. This resin shows a high selectivity for radium in a large range of acid concentrations and no affinity or possible elution of ²²⁶Ra interfering elements. The distribution coefficients of Ra and other elements over a wide range of acid (HCl and HNO₃) concentrations were obtained. Due to the high radium selectivity, the new developed protocol uses only 50 mg of dry resin and its performance was evaluated using 100 mL of three natural waters with different ionic strengths, spiked with a known quantity of ²²⁶Ra. Radium was successfully separated and preconcentrated yielding recoveries ranging between 72% and 86%. In parallel with the characterisation of the resin sorption properties, a detailed study of polyatomic interferences was performed on our ICP-MS allowing to identify the prominent elements favouring interferences at m/z = 226. Furthermore, a ²²⁶Ra sensitivity comparison between different ICP-MS instruments and configurations was done in order to determine high sensitivity conditions for radium analysis.

Direct analysis of 210Pb in drinking water by liquid scintillation counting after sulfate precipitation

Lead-210 in drinking water can be rapidly determined by liquid scintillation counting (LSC) using a new sulfate precipitation method. In this method, ²¹⁰Pb was first preconcentrated from water using iron hydroxide co-precipitation followed by sulfate precipitation to decontaminate most of non-alkaline earth elements. The Pb in the sulfate precipitate was then dissolved in strong alkaline solution, while alkaline earth elements (Sr, Ba, Ra) were separated as the sulfate/carbonate precipitate. To optimize the method, the influences of different acids and sulfate concentration on sulfate precipitation as well as the effects of pH, the added SO₄^2-/CO₃^2- concentrations and the Sr/Ba contents in the sulfate precipitate on the dissolution of PbSO₄ were studied. In addition, X-ray fluorescence (XRF) analysis was applied for rapid determination of the chemical recovery and triple-to-double coincidence ratio (TDCR) quench correction curve for counting of ²¹⁰Pb by LSC was established. The method was validated using 5 L of tap water samples and minimum detectable activity concentration (MDC) of ∼0.016 Bq·L^-1 was achieved, which is sufficiently sensitive to meet the guidance level of 0.1 Bq·L^-1 for ²¹⁰Pb in drinking water as recommended by the World Health Organization (WHO).

A review of the analytical methodology to determine Radium-226 and Radium-228 in drinking waters

Radium-228 (228Ra) and Radium-226 (226Ra) isotopes in drinking water are significant from the aspect of radiation protection and human health. In this paper, the three most common preconcentration methods, i.e.coprecipitation, absorption and evaporation, were reviewed with emphasis on routinely measurement techniques. The reviewed measurement techniques include low background γ-spectrometry, α-spectrometry and liquid scintillation counting. The γ-spectrometry technique is the good selection, when the maximum sensitivity is considered. The Environmental Protection Agency guideline has provided the maximum concentration level 0.74 Bq/L for 226Ra and 228Ra. Also, the World Health Organization guideline limit is 1 Bq/L and 0.1 Bq/L for 226Ra and 228Ra, respectively.