Development of a kelp powder (Thallus laminariae) Standard Reference Material

Abstract

A Standard Reference Material (SRM) of seaweed, SRM 3232 Kelp Powder (Thallus laminariae) has been developed to support food and dietary supplement measurements in compliance with the Food Safety Modernization Act (FSMA) and the Dietary Supplement Health and Education Act of 1994 (DSHEA). The material was characterized for nutritional minerals, arsenic species, isomers of vitamin K, proximates, and toxic elements. Kelp is a rich source of vitamins and minerals, and it is an excellent source of dietary iodine. Kelp also contains a large amount of arsenic, which is toxic as inorganic species but much less so as organic species. To capture the dietary profile of kelp, certified values were issued for As, Ca, Cd, Cr, Cu, Fe, Hg, I, K, Mg, Mn, Mo, Na, Pb, and Zn. Reference values for proximates were assigned. For the first time, a certified value for iodine, reference values for isomers of vitamin K, and reference values for arsenic species including arsenosugars were assigned in a seaweed. SRM 3232 fills a gap in Certified Reference Materials (CRMs) needed for quality assurance and method validation in the compositional measurements of kelp and similar seaweeds used as food and as dietary supplements. Graphical Absract Arsenic species and isomers of vitamin K were determined in the development of SRM 3232 Kelp Powder (Thallus laminariae).

What is novel about certified reference materials?

“…A recent paper by Yu et al [20] describing a kelp powder SRM is, in my opinion, a excellent model for a trace element CRM paper. SRM 3232 Kelp Powder (Thallus laminariae) was developed to support measurements for compliance with food and dietary supplement regulations.…”

“…Kelp was selected because it is a rich source of dietary iodine and vitamin K 1 , and it contains high levels of total arsenic, including both toxic inorganic species and less toxic organic species. Yu et al [20] explained the need for the kelp material and compared the elemental content of the kelp powder SRM to similar seaweed-matrix CRMs from other NMIs. Using multiple analytical techniques, certified values for 15 nutritional and toxic elements were assigned.…”

Evolution of reference materials for the determination of organic nutrients in food and dietary supplements—a critical review

“…In addition to a value for total vitamin K 1 , the recent KRISS infant formula CRM has values for trans - and cis -isomers of vitamin K 1 . NIST recently issued SRM 3232 Kelp Powder ( Thallus laminariae ) [83], which has certified and reference values assigned for 20 trace elements including total arsenic, arsenic species, and arsenosugars. Since kelp is a good source of vitamin K 1 , reference values were also assigned for total vitamin K 1 (0.431 mg/kg ± 0.081 mg/kg), cis -vitamin K 1 (0.0353 mg/kg ± 0.0067 mg/kg) and trans -vitamin K 1 (0.396 mg/kg ± 0.075 mg/kg) using an ID LC-MS/MS method [83].…”

“…NIST recently issued SRM 3232 Kelp Powder ( Thallus laminariae ) [83], which has certified and reference values assigned for 20 trace elements including total arsenic, arsenic species, and arsenosugars. Since kelp is a good source of vitamin K 1 , reference values were also assigned for total vitamin K 1 (0.431 mg/kg ± 0.081 mg/kg), cis -vitamin K 1 (0.0353 mg/kg ± 0.0067 mg/kg) and trans -vitamin K 1 (0.396 mg/kg ± 0.075 mg/kg) using an ID LC-MS/MS method [83]. The vitamin K 1 levels in the kelp are similar to the level in the KRISS infant formula and about 40% of the level in the NIST infant formula, which are both fortified materials.…”

Between-bottle homogeneity test of new certified reference materials employing wavelength dispersive X-ray fluorescence spectrometry

“…It is recommended to test homogeneity in term of the certified properties. As the proposed CRMs in the current study will be certified for some macro-, micro- and trace elements, inductively coupled plasma-mass spectrometry (ICP-MS) and instrumentation neutron activation analysis (INAA) are recommended as the most reliable and precise techniques for elemental analysis [3, 4]. However, ICP-MS requires critical sample treatment procedures while INAA is expensive technique and requires critical precautions for safety.…”