对于NMIJ碳酸盐缓冲溶液的例子,用于初级pH方法的批量复制性
Toshiaki Asakai1, Igor Maksimov2, Sachiko Onuma2
1National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, Japan. t-asakai@aist.go.jp.
Analytical and bioanalytical chemistry
|April 4, 2024
概括
本研究评估了日本国家计量研究所初级pH标准生产的批量对批量可重复性. 结果表明pH可重现率约为0.010,突出显示了基于配方的碳酸盐pH标准的潜在准确性风险.
科学领域:
- 计量学 计量学是一门学科.
- 分析化学 分析化学
- 电化学 电化学 电化学
背景情况:
- 日本国家计量研究所 (NMIJ) 提供初级pH缓冲器,使用Harned细胞进行认证.
- 二级和工作pH标准是由指定的实验室从这些初级缓冲器中得出的.
- 在各种科学和工业应用中,初级pH标准对于准确的pH测量至关重要.
研究的目的:
- 为了估计NMIJ的初级pH标准生产的批量对批量的可重复性.
- 为了评估试剂纯度对初级碳酸盐缓冲剂pH值的影响.
- 在使用基于配方的碳酸盐pH标准时识别pH精度的潜在风险.
主要方法:
- 在NMIJ对初级碳酸盐缓冲器的历史认证数据的分析.
- 主要pH缓冲器使用主性pH方法的认证.
- 试剂源材料通过pH测量和酸度重度测量逆位评价进行评价.
主要成果:
- 研究的重点是二碳酸盐和碳酸盐的0.025 mol kg-1 均等醇溶液,该溶液因其测量复杂性而被选择.
- 实验确定了初级碳酸盐缓冲器的pH可重现性,发现它大约为0.010.
- 试剂的纯度显著影响碳酸盐缓冲剂的pH值.
结论:
- 在NMIJ初级pH标准生产的批量对批量可重复性估计约为. 0.010 的pH单位.
- 原材料的纯度是影响初级碳酸盐pH标准准确性的关键因素.
- 建议在使用基于配方的碳酸盐pH标准时谨慎使用,因为这可能会对pH的准确性造成风险.
相关概念视频
01:18Titration of Polyprotic Base with a Strong Acid
793
The titration of a polyprotic base such as sodium carbonate with a strong acid such as hydrochloric acid results in two equivalence points on the titration curve. At the first equivalence point, the carbonate ions in the base are completely converted to bicarbonate ions. The second equivalence point corresponds to the complete conversion of bicarbonate ions to carbonic acid, which dissociates into carbon dioxide and water. The region before the first equivalence point corresponds to the...
793
02:45Calculating pH Changes in a Buffer Solution
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A buffer can prevent a sudden drop or increase in the pH of a solution after the addition of a strong acid or base up to its buffering capacity; however, such addition of a strong acid or base does result in the slight pH change of the solution. The small pH change can be calculated by determining the resulting change in the concentration of buffer components, i.e., a weak acid and its conjugate base or vice versa. The concentrations obtained using these stoichiometric calculations can be used...
53.2K
01:08Titration of a Weak Acid with a Weak Base
2.8K
Weak acids and bases do not undergo dissociation completely, and titrations between these two are rarely studied. When such studies are performed, say, for the titration of a weak acid with a weak base, the titration curve plots the change in pH as a function of the volume of base added. Take the titration of acetic acid with ammonia, for instance. During the titration, these two species form ammonium acetate and water, but the pH change is slow and gradual.
As a result, there is no simple...
As a result, there is no simple...
2.8K
01:20Titration of a Weak Base with a Strong Acid
5.0K
The titration curve of a weak base like ammonia with a strong acid like hydrochloric acid is the mirror image of the titration curve of a weak acid with a strong base.
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
5.0K
02:19Buffer Effectiveness
49.0K
Buffer solutions do not have an unlimited capacity to keep the pH relatively constant . Instead, the ability of a buffer solution to resist changes in pH relies on the presence of appreciable amounts of its conjugate weak acid-base pair. When enough strong acid or base is added to substantially lower the concentration of either member of the buffer pair, the buffering action within the solution is compromised.
The buffer capacity is the amount of acid or base that can be added to a given volume...
The buffer capacity is the amount of acid or base that can be added to a given volume...
49.0K
02:28Titration Calculations: Strong Acid - Strong Base
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Calculating pH for Titration Solutions: Strong Acid/Strong Base
A titration is carried out for 25.00 mL of 0.100 M HCl (strong acid) with 0.100 M of a strong base NaOH. The pH at different volumes of added base solution can be calculated as follows:
(a) Titrant volume = 0 mL. The solution pH is due to the acid ionization of HCl. Because this is a strong acid, the ionization is complete and the hydronium ion molarity is 0.100 M. The pH of the solution is then:
A titration is carried out for 25.00 mL of 0.100 M HCl (strong acid) with 0.100 M of a strong base NaOH. The pH at different volumes of added base solution can be calculated as follows:
(a) Titrant volume = 0 mL. The solution pH is due to the acid ionization of HCl. Because this is a strong acid, the ionization is complete and the hydronium ion molarity is 0.100 M. The pH of the solution is then:
29.6K