凱氏法
No significant differences in concentration among sub-samples were found.The certified value and uncertainty were based on the analytical results of eight labs by Kjeldahl method. 其標(biāo)準(zhǔn)值和不確定度是由多家實(shí)驗(yàn)室用凱氏法進(jìn)行分析測(cè)定,并經(jīng)數(shù)理統(tǒng)計(jì)處理后確定的。