Improved continuous packaging method of the certified reference material for low water content in liquid

Wang, Ting; Wang, Haifeng; Su, Heng; Huang, Xingliang; Song, Xiaoping; Ma, Kang

doi:10.1007/s00769-018-1318-8

Cited by 1 publication

(9 citation statements)

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“…According to ISO Guide 35, reference materials can be certified using a primary method. 31 The gravimetric method is a primary method and is widely used to prepare CRMs of compounds or elements in solution. 31 Therefore, the CRMs for the water content of crude oil can be certified using the gravimetric method alone.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The uncertainty of the certified value was evaluated in accordance with the ISO Guide 35. 31 Equation 3 was used as the measurement model. The uncertainty of each variable was evaluated.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The certification method conformed with the specifications of ISO Guide 35, and the certified value was traceable to the SI unit of mass. 31 This gravimetric method can also be employed to develop CRMs for the water content of heavy crude oil and might be used in the development of other CRMs for inhomogeneous matrices of liquids or solids. The verification of the distillation method using these five CRMs indicated that the repeatability and accuracy of this method might be unsatisfactory for light crude oil.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The RSD values of the results ranged from 5.6 to 10% (Table ), which indicated that the water content of the blank crude oil was homogeneous and that the uncertainty arising from the inhomogeneity of the water content of the blank crude oil was very low. The rinsing of the air flowing into the headspace of the big container using a pre-equilibrated bottle might have helped to reduce the effect of the bias between the ambient humidity and the equilibrated humidity of the blank crude oil on the homogeneity of the water content between different bottles …”

Section: Resultsmentioning

confidence: 99%

“…7,13 These two RMs were determined using only one method (the modified KFCT method), which does not conform to the requirements for the certification of RMs specified by ISO guide 35. 31 Therefore, these two RMs provide reference values, not certified values. The reference values of these two RMs (approximately 100 mg/ kg) are much lower than that of commercial crude oil (1.0 to 10 mg/g), and each ampule of these two RMs contains only 10 mL of crude oil.…”

Section: ■ Introductionmentioning

confidence: 99%

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Development and Application of Certified Reference Materials of Light Crude Oil for Water Content

Zheng,

Wang,

2023

ACS Omega

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The water content of the crude oil needs to be measured accurately. The analytical methods that are used, including distillation and Karl Fischer coulometric titration (KFCT), require verification using certified reference materials (CRMs) of crude oil for the water content. In the present study, five CRMs of light crude oil with large volumes and various certified water contents (1−10 mg/g) were developed using the gravimetric method. Each candidate CRM was prepared individually, including the addition of pure water to the dried blank crude oil and weighing the masses of the added water and the blank crude oil. The water content of the blank crude oil was measured using azeotropic distillation-KFCT (AD-KFCT). The certified water content for the CRM was calculated by using the water content of the blank crude oil, the masses of the added pure water, and the blank crude oil. The certified water content and the expanded uncertainty (U, k = 2) of the five CRMs were 1.12 (0.04), 2.14 (0.06), 3.14 (0.10), 5.14 (0.15), and 10.05 (0.27) mg/g. These CRMs were used to verify the accuracy of analytical methods, including distillation, KFCT, and AD-KFCT methods.

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Section: ■ Results and Discussionmentioning

confidence: 99%

“…The uncertainty of the certified value was evaluated in accordance with the ISO Guide 35. 31 Equation 3 was used as the measurement model. The uncertainty of each variable was evaluated.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%