Preparation and certification of a reference material for the determination of nutrients in seawater

Abstract

There is an urgent need for natural water reference materials certified for nutrients. In 1996, NRC collected seawater for a proposed CRM at a depth of 200 m in the North Atlantic; this was immediately filtered through 0.05-microm cartridge filters into 50-L carboys. The water was later homogenized in the NRC laboratories in Ottawa and stabilized via gamma irradiation. Over six years of stability testing no significant deterioration was detected. In addition to the usual customary standard colorimetric procedures, alternative analytical methods were developed to enable the certification process. The production of a CRM called MOOS-1 will be discussed. Certified values, with uncertainty components addressing the homogeneity, stability, and characterization of the material, were calculated to be: orthophosphate=1.56+/-0.07 micro mol L(-1), silicate=26.0+/-1.0 micro mol L(-1), nitrite=3.06+/-0.15 micro mol L(-1), and nitrite and nitrate=23.7+/-0.9 micro mol L(-1).

Toward a Harmonization for Using in situ Nutrient Sensors in the Marine Environment

“…Nutrients CRMs for seawater have only become readily available in recent years 6 . They have been developed since the 2000s by: the National Research Council Canada (NERC, MOOS CRM; Clancy and Willie, 2004), VKI Eurofins Denmark, the Korean Institute of Ocean Science and Technology (KIOST) and the General Environmental Technos Co., Ltd. (Kanso) in Japan (Ota et al, 2010). These CRMs are essential to achieve one of the most important goals of the chemical oceanographers, i.e., allowing the comparability of nutrient analyses with a level of analytical precision better than 1% (Hydes et al, 2010;Rees et al, 2018).…”

Determination of phosphate in seawater by CZE with on‐line transient ITP

“…Then the three groups were mixed to give the composition shown in Table 1. A seawater certified reference material for nutrients, MOOS-1 [30], was obtained from NRC (Ottawa, Canada). From Nacalai Tesque, L-ascorbic acid, hexaammonium heptamolybdate tetrahydrate, bis[(1)-tartrato]diantimonate(III) dipotassium trihydrate, sulfuric acid, and ammonium amidosulfate used for MBS were obtained.…”

“…The proposed method was verified through the determination of phosphate in a seawater certified reference material for nutrients, MOOS-1 [30], distributed by the National Research Council of Canada (NRC). Moreover, seawater samples were taken from the surface and the seabed around the coastal area of Osaka Bay; phosphates in samples were determined by the proposed CZE procedure and MBS used conventionally for phosphate analyses.…”

Feasibility of gamma irradiation as a stabilisation technique in the preparation of tissue reference materials for a range of shellfish toxins

“…Irradiation is traditionally used to prevent microbial spoilage of food products, and it has been used to stabilise seawater RMs for nutrients [4], but there are few literature reports of its use for preparation of biological RMs. The technique is typically applied in the preparation of RMs to be certified for inorganic substances, because many organic compounds are destroyed by such treatment.…”