Table 2.

Equations used in mass balance method

Equation	No	Description
$P_{\text{MB}}\%=\left(1-x_{\text{oi}}\right)\left(1-x_{\text{mo}}-x_{\text{re}}-x_{\text{sa}}\right)\times 100\%$ where $x_{\text{oi}}=\frac{{\sum }_{\text{i}=1}^{\text{n}}{A}_{\text{oii}}}{A_{\text{tot}}}$	(8)	PMB is the purity of sample determined by MB; xoi is the amount of organic impurities; xmo is the amount of water; xre is the amount of residual solvent; xsa is the amount of sulfated ash; Aoi is the corrected chromatographic peak area of organic impurities. Atot is the corrected chromatographic peak area of all compounds
$P_{\text{qNMR}}\%=x_{\text{qNMR}}-x_{\text{mo}}-x_{\text{re}}-x_{\text{sa}}\times 100\%$ where $x_{\text{qNMR}}=\frac{I_{\text{MC}}}{I_{\text{IS}}}·\frac{N_{\text{IS}}}{N_{\text{MC}}}·\frac{M_{\text{MC}}}{M_{\text{IS}}}·\frac{m_{\text{IS}}}{m_{\text{MC}}}·P_{\text{IS}}$	(9)	PqNMR is the purity of sample determined by qNMR; xqNMR-Calc is the calculated purity from 1H NMR experiments; IIS and IMC are integrated area of standard and sample; NIS and NMC are numbers of spin of standard and sample; MIS and MMC are molar masses of standard and sample; mIS and mMC are weights of standard and sample; PIS is the purity of internal standard
${\left(\frac{u(x_{\text{oi}})}{x_{\text{oi}}}\right)}^2=\sum {\left(\frac{u(A_{\text{oi}})}{A_{\text{oi}}}\right)}^2+{\left(\frac{u(A_{\text{tot}})}{A_{\text{tot}}}\right)}^2$	(10)	u(xoi) is the uncertainty of organic impurities determined by MB; u(Aoi) is the uncertainty of the corrected chromatographic peak area of organic impurities. u(Atot) is the uncertainty of the corrected chromatographic peak area of all compounds
$u(x_{\text{qNMR}})=u(x_{\text{mo}})=u(x_{\text{re}})=u(x_{\text{sa}})\text{= S/}\sqrt{10}$	(11)	u(xqNMR) is the uncertainty of Sal A determined by qNMR; u(xmo), u(xre) and u(xsa) is the uncertainty of moisture, residual solvent and sulfated ash determined by MB, respectively; S is the standard deviation of relative experiments
$u\left(\text{MB}\right)=\sqrt{u^2\left(x_{\text{oi}}\right)+u^2\left(x_{\text{mo}}\right)+u^2\left(x_{\text{sa}}\right)}$	(12)	u(MB) is the uncertainty of purity determined by MB
$u\left(\text{qNMR}\right)=\sqrt{u^2\left(x_{\text{qNMR}}\right)+u^2\left(x_{\text{mo}}\right)+u^2\left(x_{\text{sa}}\right)}$	(13)	u(qNMR) is the uncertainty of purity determined by qNMR
$u_{\text{CRM}}=\sqrt{u{(MB)}^2+u{(\text{q}NMR)}^2+u_{\text{h}}^2+u_{\text{sts}}^2+u_{\text{lts}}^2}$	(14)	uCRM is the combined standard uncertainty of certified property value
$U_{\text{CRM}}=u_{\text{CRM}}k$	(15)	UCRM is the expanded uncertainty of certified property value; k is the coverage factor