Name: preparing standard solutions in the lab
Uploaded: 2024-12-05T18:31:54.000Z
Duration: 1 min 14 s
Channel: JoVE

표준 용액은 정확하게 알려진 양의 물질이 포함된 용액입니다. 그것은 1 차 표준 - 매우 순수하고 높은 몰 질량, 친수성 및 안정된 물질로 준비됩니다.
준비 과정에는 계량 보트에서 적절한 양의 1차 표준물질을 정확하게 계량하고 깔때기를 사용하여 부피 측정 플라스크로 옮기는 작업이 포함됩니다. 남아 있는 고체 물질이 있는지 확인하기 위해 빈 계량 보트의 무게를 다시 측정합니다.
소량의 증류수를 첨가하여 깔때기의 고형물을 플라스크로 씻어냅니다. 부피 측정 플라스크는 소용돌이쳐 고체를 완전히 용해시킵니다. 레벨이 보정 표시에 가까워질 때까지 더 많은 물을 추가합니다. 이 시점에서 물을 피펫으로 주입하여 용액 수준을 보정 표시까지 정확하게 증가시킵니다.
플라스크는 완전한 혼합을 보장하기 위해 여러 번 닫히고 뒤집힙니다. 플라스크에 화학 성분, 농도 및 준비 날짜를 표시하십시오.
이 1차 표준 솔루션은 2차 표준물질(덜 순수하고 덜 안정적인 물질)을 표준화하는 데 사용됩니다.

표준 용액

표준 용액은 농도 또는 구성이 정확히 알려진 용액을 말합니다. 1차 표준은 분석 화학에서 가장 일반적으로 사용되는 용매인 물에 완전히 녹는 고순도, 높은 몰 질량, 안정된 물질입니다. 1차 표준 용액은 농도는 알려져 있지만 덜 순수하고 안정된 물질인 2차 표준을 표준화하는 데 사용할 수 있습니다. 표준 용액은 분석 절차에서 정확하고 신뢰할 수 있는 결과를 얻는 데 필수적이므로 실험실 환경에서 작업하는 모든 사람에게 이를 이해하는 것이 중요합니다.

1차 표준을 사용하여 표준 용액을 준비하는 데는 여러 단계가 포함됩니다.

<ol style=" display: flex; flex-direction: column; padding: 0 0 0 16px;">
	<li>1차 표준 무게 측정: 저울을 사용하여 적절한 양의 1차 표준을 무게 측정합니다. 정확한 측정을 제공할 수 있는 저울을 사용하는 것이 중요합니다.</li>
	<li>표준을 부피 플라스크로 옮기기: 깔때기를 사용하여 무게가 있는 1차 표준을 깨끗하고 건조한 부피 플라스크로 조심스럽게 옮깁니다. 모든 고체가 저울에서 플라스크로 옮겨졌는지 확인합니다. 옮긴 후 빈 저울을 다시 달아 잔류물이 없는지 확인합니다.</li>
	<li>깔때기 세척: 소량의 증류수를 사용하여 깔때기에서 고형물을 용적 플라스크로 씻어냅니다. 이렇게 하면 모든 1차 표준이 용액에 용해됩니다.</li>
	<li>고형물 용해: 용적 플라스크를 돌려 고형물이 완전히 용해되도록 합니다. 고형물이 완전히 용해될 때까지 점차적으로 물을 추가해야 할 수도 있습니다.</li>
	<li>교정선에 접근: 더 많은 증류수를 추가하여 용액 수준을 용적 플라스크 목의 교정 표시에 가깝게 만듭니다. 교정선을 초과하지 않도록 용매를 더 추가하기 전에 고형물이 완전히 용해되었는지 확인합니다.</li>
	<li>메니스커스 조정: 피펫을 사용하여 메니스커스(액체 표면의 곡선) 바닥이 교정 표시와 정확히 일치할 때까지 한 방울씩 물을 추가합니다. 이 단계는 용액의 용량과 농도가 올바른지 확인합니다.</li>
	<li>용액 혼합: 용적 플라스크를 단단히 닫고 여러 번 뒤집어 용액이 완전히 혼합되도록 합니다.</li>
	<li>라벨: 메스플라스크에 화학 성분, 용액 농도, 제조일을 라벨로 표시합니다. 이 정보는 용액을 올바르게 식별하고 사용하는 데 도움이 됩니다.</li>
</ol>

표준 용액은 정확하게 알려진 농도 또는 조성을 가진 용액을 나타냅니다. 기본 표준은 매우 순수하고 높은 몰 질량이며 안정되어 있습니다.

Education

교육

JoVE Core

Analytical Chemistry

분석 화학

Unit 1

제1단원

Method Development and Sampling Techniques

분석법 개발 및 시료 채취 기술

method-development-and-sampling-techniques

KEY TERMS AND CONCEPTS

주요 용어 및 개념

Standard Solutions

preparing standard solutions in the lab

Standard solutions are prepared to have a precisely known concentration or composition. In analytical chemistry, this accuracy is important because it supports reliable results. A primary standard is a highly pure, stable substance with a high molar mass. It is fully soluble in water, which is the most commonly used solvent in analytical chemistry.

A primary standard solution can be used to standardize a secondary standard. Secondary standards have known concentrations, but they are usually less pure and less stable. This makes primary standards especially useful when exact measurements are needed in a laboratory setting.

The preparation starts by weighing the primary standard with a balance that gives precise measurements. The solid is then transferred through a funnel into a clean, dry volumetric flask. It is important to move all of the material from the weighing boat into the flask. The empty weighing boat is reweighed to confirm that no residue remains.

Next, small amounts of distilled water are used to wash any solid from the funnel into the volumetric flask. The flask is then swirled until the solid dissolves completely. More water is added gradually until the liquid is close to the calibration line on the neck of the flask.

The final volume is set by adjusting the meniscus, which is the curved surface of the liquid. A pipette is used to add water drop by drop until the bottom of the meniscus lines up exactly with the calibration mark. The flask is then closed and inverted several times to mix the solution well. At the end, the flask is labeled with the chemical composition, the solution concentration, and the preparation date.

Preparing Standard Solutions in the Lab

development of analytical methods

Analytical Methods: Technique to Protocol

Analytical methods follow a clear path from technique to protocol. In analytical chemistry, a technique is the scientific principle used to explain a chemical measurement. A method applies that technique to a sample of interest. The next steps are procedure and protocol. A procedure gives the directions for carrying out the analysis with an analytical method. A protocol is the detailed set of guidelines for that procedure, and it should be followed closely to get the desired results. <br...

quality control

Quality Control Charts and Lab Records

Quality control charts, proficiency testing, and lab records are key parts of quality control in a laboratory. These steps help keep a system under statistical control. They also help track data, show trends, and spot variations that may affect the accuracy of an analysis. One common tool is a quality control chart. This chart plots one or more analytical characteristics over time. The measured values are taken at different times during the analysis and compared with the known value of...

quality assurance

Quality Checks in Analytical Testing

Quality assurance in analytical testing brings together the checks that help a system perform properly. It includes quality control, quality assessment, and internal corrective measures. These parts work in a cycle to support reliable results. Quality control happens before and during the analysis. Quality assessment takes place during and after the investigation. Internal corrective measures are then based on the results of post-analysis quality assessment, or they may be applied before a new...

data validation

How Analytical Methods Are Checked

Method validation checks whether an analytical chemistry method gives reliable results. It is especially important when the same method is used with different sample matrices or when the procedure is changed. Validation helps show that the method still meets acceptable standards in each case. Several key checks are used in method validation. Specificity means the method can measure the target analyte without interference from other substances. Linearity means the result changes in direct...

qualitative analysis

Classical and Instrumental Sample ID

Qualitative analysis identifies the elements, ions, or compounds in an unknown sample. It is the first step in the hierarchy of analytical goals. That makes it the starting point for scientific study before quantitative analysis or other forms of analysis. Two main approaches are used in qualitative analysis: classical methods and instrumental methods. Classical methods depend on the visible or sensory result of a chemical reaction, such as a color change, a precipitate, or even a smell. These...

quantitative analysis

Measuring Analyte Concentration

Quantitative analysis measures the amount of a specific substance, called the analyte, in a sample. If the sample composition is unknown, qualitative analysis comes first. That step identifies the components so the correct substances can be measured during the quantitative phase. This method depends on two key measurements. Scientists measure the sample quantity and also a property that is proportional to the amount of analyte. Together, these measurements help determine the analyte...

instrument calibration

Calibrating Lab Instruments for Accurate Results

Calibration helps lab instruments produce accurate and consistent results. It is important in manufacturing, healthcare, testing laboratories, and scientific research. Each instrument needs a calibration process that matches its design and function. This process improves data accuracy and helps results stay reliable. An analytical balance measures mass and needs regular calibration to stay precise. It is calibrated by comparing its readings with known standard weights. These weights act as...

glassware calibration

Calibrating Lab Glassware for Accurate Volume

Calibrating lab glassware helps students measure liquids accurately in the analytical laboratory. It reduces volume errors and supports consistent results across measurements. This matters when using volumetric flasks, pipettes, burettes, and other tools that depend on precise volume readings. Volumetric flasks are used to prepare aqueous solutions with a precise final volume. They have a calibration line on the neck. To calibrate one, fill it with distilled water until the meniscus, the...

standard solutions

Standard solutions are prepared to have a precisely known concentration or composition. In analytical chemistry, this accuracy is important because it supports reliable results. A primary standard is a highly pure, stable substance with a high molar mass. It is fully soluble in water, which is the most commonly used solvent in analytical chemistry. A primary standard solution can be used to standardize a secondary standard. Secondary standards have known concentrations, but they are usually...

blank solutions

Blank Solutions in Analytical Testing

Blank solutions are used in analytical testing to show the background signal before a sample is measured. A blank solution does not contain the analyte, which is the substance of interest being tested or measured. It is usually made with the same reagents and procedure as the sample solution, but without the analyte. The main purpose of a blank solution is to control for background interference and contamination. Reagents, solvents, or lab equipment can sometimes create a detectable signal on...

sampling methods: overview

How Sampling Shapes Lab Results

Sampling shapes lab results by determining how a smaller sample represents a larger population. In analytical chemistry, testing an entire population is often impractical or impossible, so samples are collected to make inferences about the whole group. The sampling method is the process used to choose individuals or items for that sample. Common sampling methods include random, judgemental, systematic, stratified, and cluster sampling. Each method can affect the quality of the data in a...

sampling methods: sample types

Sampling Materials in Solid, Liquid, Gas

Sampling materials are grouped as solid, liquid, or gas. The type of sample helps decide the right collection method. Solid samples can include sediments from water bodies, soil, metals, and biological tissues. Sediment sampling from water bodies can be done in two common ways. Grab sampling uses a device to collect a discrete sample from the bottom with minimal disturbance. These samples may not show the full area because conditions can vary from place to place. Piston coring collects a...

sampling plans

Choosing Samples for Reliable Results

Sampling is a key step in analytical chemistry. It helps researchers collect data that represents a larger population. The main sampling methods in this topic are random, judgmental, systematic, stratified, and cluster sampling. Random sampling gives each member of the population an equal chance of being chosen. Researchers often use a random number generator or a lottery-style method. For example, a polymer sheet can be divided into 1 cm x 1 cm sections, and 10 sections can be selected at...

sample preparation for analysis: overview

Preparing Samples by State and Form

Sample preparation depends on the state and form of the sample before analysis. It helps make the sample ready for accurate measurement. The main goal is to extract the analyte, which is the substance being measured, and remove parts that could interfere with the analysis. Solid samples often need the most handling. Large solids are usually ground, crushed, or milled to make them smaller and increase surface area. The sample is then sieved and mixed so it has a uniform composition. After that,...

sample preparation for analysis: advanced techniques

sample-preparation-for-analysis-advanced-techniques

Preparing Complex Samples for Analysis

Preparing complex samples for analysis often requires special digestion and fusion methods. Samples with inorganic or organic material can be hard to dissolve or break down. Common sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion. These steps help turn difficult samples into forms that can be tested reliably and again with similar results. Acid digestion is often used for inorganic materials that do not dissolve in water. It is useful for soil and...

sample handling

Sample Transport and Storage Basics

Sample transport and storage help keep specimens intact before testing. Moving a sample from the collection point to the laboratory requires careful handling. The sample should be sealed well and clearly labeled. These steps help prevent cross-contamination and support reliable results. Temperature control is also important during transport. Some samples travel in insulated containers, cool packs, or refrigerated vehicles so they stay within the needed temperature range. After the samples...

contaminants and errors

Sampling Errors in Sample Preparation

Sampling errors in sample preparation can affect the accuracy of laboratory results. Two common problems are concentration bias from poor sample splitting and contamination from reducing particle size by grinding or homogenization. Recognizing these errors helps make analysis more reliable. The number of samples also matters when a target population follows a normal distribution. In that case, the sample size ns can be found with a formula that uses the t-value for the chosen confidence level,...

key terms and concepts

Learn how standard solutions are prepared from a primary standard using a volumetric flask, accurate weighing, meniscus adjustment, and proper labeling.

Preparing Standard Solutions in the Lab | JoVE K12

analytical chemistry

JoVE Core Analytical Chemistry simplifies complex chemical principles by breaking them down into clear, engaging animations, making topics from SI Units to NMR spectroscopy more accessible and straightforward. Additionally, the scientist-in-action videos highlight the application of these concepts in real-world research conducted in laboratories globally.

Preparing Standard Solutions in the Lab

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