Introduction
PH Strip Merck, also known as a litmus test, are used to determine the pH value of a liquid, e.g. pH strips for water to spray the crop with. The pH of a liquid indicates whether a liquid is acidic, neutral or alkaline. In some cases, this is important to know, for example when you want to determine whether a disinfectant is still effective. In this article, our specialist provides more information about how to read and use pH test stri
1. Informal Experiments: How do pH strips work?
By Helen Kollias, PhD
Cabbage: not just for coleslaw any more! Learn about pH strips and make your own, right in your own kitchen.
PH strips are pieces of paper that change color depending on the pH – the acidity or alkalinity – of a liquid. PH strips are a cheap and relatively accurate way of measuring the pH of any liquid, in our case urine. A strip of filter paper is soaked with different pH indicators (more on that later), allowed to dry and voila: pH strips.
Most common pH strips are designed to test urine, water and saliva.
There are a variety of pH strips available. They differ by sensitivity and what range of pH they are designed for. The more sensitive the pH strip, the smaller the range in which it works.
Why the limitation? Well, you can only differentiate so many colours. Figuring out whether your strip is bluish-green or greenish-blue can be difficult.
Now, depending on what pH range you want and how sensitive you need the strip to be, you adjust your indicators. So you can have a pH strip with a range of 1-14, but not very sensitive; or you can have a pH strip with a range of 5.5-8.5 that can measure changes as small as 0.25 in pH.
The next question is how do you know what pH is bluish-green?
To make a colour legend (i.e., to figure out what colour goes with what pH) the pH strips are dipped into solutions with different known PHS. If you dip your pH strip into a solution with a pH of 5 and the strip is dark blue then you know that blue means pH of 5, and so on until you cover the range of the strips. You don’t have to do this part; someone’s probably already done it for you — the colour legend will be included with the package of strips.
1. pH indicators
pH indicators are usually weak acids or weak bases that change colour at specific pHs. For instance, methyl red is a common indicator that’s red at pH of 5 and yellow at a pH of 6.
pH indicator chart
2. Super-mini-chem lecture
Why do they change colour? I’ll explain the theory very briefly. There are a few different ways of defining acids and bases, but I think the easiest way to understand them is to think of them as chemicals that exchange a proton. In this case, the proton comes from a hydrogen ion – a hydrogen with a positive charge, which gives us the “H” in “pH”.
Chemicals that donate a proton are acids; chemicals that take up a proton are bases (aka alkaline). So hydrogen donor – acid; hydrogen acceptor – base.
Colour changes occur when the acid or base accepts or donates a proton. When this happens depends on the chemical’s specific characteristics. Some indicators are more complex and have more than one colour change.
See our experiment below for an indicator with multiple changes: first from red to blue, then from blue to yellow.
Luckily, there are a wide range of pH indicators that change at a bunch of different pHs as well as change to a bunch of different colours, so that specific pH strips can be made.
3. Experiment
If you’re interested you can make your own pH strip with a red cabbage, some boiling water and a McGyver wig (optional).
First, purée your red cabbage with 2 cups of boiling water (and you thought your blender was only good for shakes!). Next, strain the bits with a fine mesh strainer and keep the liquid. (You can make cabbage soup with the leftovers.) The liquid is your pH indicator (or cabbage tea — call it what you will).
Get a coffee filter, cut it in strips and soak the strips in the cabbage tea – I mean pH indicator – for a few hours. Take the strips out and let them dry. Make sure not to drip any, as it will stain. Ta da! Your very own pH strips!
Your pH strips will most likely be violet-bluish (pH 7) to start (see below). Try dipping your strips into vinegar, lemon juice, cola, baking soda solution, antacids or bleach (be very careful) and watch it change colour. Really, the list is endless – though you might not see much of a difference with some. Use a different strip each time for best results. Have fun!
2. A Brief Note on Determining the pH of Samples
Chemicals have their distinct nature – they can be neutral or acidic or basic. These characteristics primarily depend on how many H+ or OH– ions a particular chemical is releasing in its aqueous solution.
For example, chemicals that release H+ ions are acidic, whereas those which release OH- ions are basic.
These experiments are an integral part of Class 10 practical chemistry syllabus. Hence, to know about the pH of samples and how to determine that, keep on reading this article!
Introduction
pH, a measure of acidity or authenticity of aqueous or other liquid solutions. pH is one of the most common terms in the field of chemistry, biology, and agronomy, converting the value of hydrogen ions — typically between 1 and 10-14 (1 g) per liter — into numbers between 0 and 14. In clean water. , neutral hydrogen ion concentration is 10-7 gram-equivalents per liter, Solution with a pH of less than 7 is considered acidic; a solution with a pH greater than 7 is considered basic, or alkaline.
The measure was originally used by Danish biochemist S.P.L. Sørensen represents a mixture of hydrogen ions, expressed in proportion to each liter of liquid solution: pH = −log (H +)
1. Definition of pH
The International Union of Pure and Applied Chemistry (IUPAC) has a slightly different pH scale based on electrochemical estimates of standard bath solution. Basically, the description uses a number:
pH = -log aH +
where aH + represents hydrogen activity, which is the active combination of hydrogen ions in solution. This may be slightly different from the actual focus. IUPAC pH measurement includes thermodynamic factors, which can affect pH.
In most cases, a standard definition of pH is sufficient.
2. PH scale
The pH range is from 0 to 14. The pH of a solution is a measure of its acidity or alkalinity (base). You have probably used litmus paper, a paper that has been treated with a natural water-soluble dye to be used as an indicator of pH, to check how much acid or base (alkalinity) is present in the solution. You may have used some to ensure that the water in the outdoor pool is handled properly.
3. PH measurement
The pH of a solution can be determined using a tool such as a pH meter or various indicators that change their color accordingly depending on the type of test solution.
- PH Meter: A measuring device called a pH meter can give pH up to two decimal places.
- PH meters are measured using bath solutions with pH known accuracy.
- Measure pH more accurately than indicators.
4. Now the pH days are used to measure the pH.
Indicators: It is a substance that can be used to identify the nature of a chemical due to its color change.
- The indicator changes color when the pH of the solution changes slightly.
- If you use clues, it is best not to color the solution to be tested. If the solution is coloured, it can affect the color of the indicators.
The universal index or pH paper provides a relative pH value.
5. Test
Hydrochloric acid (HCl):
- Hydrochloric acid occurs as an aqueous solution or as a gas of hydrogen chloride (anhydrous hydrochloric acid).
- Hydrogen chloride gas is a colorless, non-combustible, edible gas with an offensive odor.
- When added to water it dissolves completely to form H+ ions and Cl–
- Its pH is < 7.
- Used in composting, textile and rubber industries.
- Color Produced in the Universal Index by Dilute Hcl.
Sodium hydroxide (NaOH):
- It is often called caustic soda and is a solid base, naturally decomposing.
- When soaked in water it separates completely to form Na+ and OH– ions.
- Its pH is > 7.
- Used to make soaps and detergents.
6. Theory:
Definition of pH
pH is defined as the negative logarithm (base 10) of hydrogen ion concentration. It is the most common way to determine the strength of base/acid. Often it is termed as “potential of hydrogen ion”. It is the molarity of H+ ion.
- Following is the pH value of different chemicals on a scale from 0 to 14.
- Acid pH<7
- a pH of Base>7
- pH of neutral =7.
7. PH Scale
A pH scale is used to determine the nature of a substance. Its value ranges from 0 to 14. This scale is logarithmic. It means that if an integer value increases or decreases, the concentration changes tenfold, accordingly.
For example, pH 2 is ten times more acidic than pH 3. Furthermore, pH 12 is 100 times more basic than pH 10.
8. PH Paper
A pH paper is a piece of paper used to find out if a solution is basic, acidic or neutral. This is determined by dipping part of the paper into a solution and observing the color change.
A pH paper changes color in different solutions due to the chemical flavin. This molecule, which is an anthocyanin, is soluble in water and changes color in the presence of various types of solutions.
The packaging a pH paper comes in often includes a color-coded scale indicating the pH. This works in the following ways .
4. PH Test Strip
1. Safety Monitors in Hem dialysis
Acid–Base (pH) Control
Newer-model fluid-delivery systems will not go into conductivity if the pH is too high or too low. However, the majority of dialysis clinics perform independent pH tests before each dialysis. Fluid delivery machines using bicarbonate dialysate may or may not have pH monitors. There may be a pH meter on the front panel dialysis display with lights that activate when an alarm condition occurs.
Monitoring Acid–Base (pH)
The pH of dialysate is commonly checked by use of a pH paper test strip or bicarbonate pH test strips. With the pH paper test strips, the color change of the dialysate-soaked test strip is compared with a list of colors for various pH values. The bicarbonate pH test strips interpret the results by comparing the indicator pad to the color chart on bottle label. Acceptable range for test results is a pH of 7.5 ± 0.5 (7.0–8.0). If the pH is below or above the acceptable limits and the conductivity meter is within acceptable limits, the dialysis should not be carried out. Both the pH and conductivity must be in acceptable limits before initiating dialysis.
2. Virginities
What to Do:
Take a brief sexual history. Ask if partners are experiencing related symptoms.
Perform speculum and bimanual pelvic examination.
Collect urine for possible culture and pregnancy tests that may influence treatment.
Swab the cervix or urethra to culture for Neisseria gonorrhoeae and swab the endocervix to test for Chlamydia (see Chapter 83, Urethritis).
Touch pH indicator paper (Hydrion pH papers, ColorpHast pH Test Strips) to the vaginal mucus. A pH greater than 4.5 suggests bacterial vaginosis or Trichomonas organisms, but this is only useful if there is no blood or semen to buffer vaginal secretions.
A normal pH (4-4.5) is found with Candida vulvovaginitis.
For wet-mount examination, dab a drop of vaginal secretions on a slide, add a drop of 0.9% NaCl and a cover slip, and examine under 400× magnification for swimming protozoa (Trichomonas vaginalis), epithelial cells covered by adherent bacilli (“clue cells” of bacterial vaginosis), or pseudohyphae and spores (“spaghetti and meatballs” appearance of Candida albicans) (Figures 95-1 and 95-2).
If epithelial cells obscure the view of yeast, add a drop of 10% KOH, smell whether this liberates the odor of stale fish (characteristic of Gardnerella organisms [bacterial vaginosis], Trichomonas organisms, and semen), and look again under the microscope for hyphae, pseudohyphae, or budding yeast.
3. Five-membered Rings with One Heteroatom together with their Benz and other Carbocyclic-fused Derivatives
3.08.3.5 Polymers and Polymer Additives
Phthalides and phthalic anhydrides are extremely common components in a huge variety of polymers, and are prepared using many chemical processes. There are over 1300 references to polymers derived from phthalic anhydrides in the Registry File of Chemical Abstracts. Phthalic anhydride itself is used in polyester resins but there are also many examples of polyimides that are derived from related anhydrides. In this section, a few examples representing a range of structure and polymerization process are presented.
Chlorophthalide 276 polymerized using a Friedel–Crafts reaction gives polymer 277, an example of a poly(arylenephthalide). In this example, a ‘novel rearrangement’ was observed during the polymerization which led to a scrambling of the chloro substituent’s position <1995MM7325>. This actually appears to be a Hayashi rearrangement, discovered in 1927.
3. Laboratory Methods for Diagnosing Sexually Transmitted Infections in Children and Adolescents
Trichomonas Vaginalis and Other Causes of Vaginitis/Vaginosis
Vaginosis and vaginitis are infections characterized by vaginal discharge and/or pruritus. The diagnoses of bacterial vaginosis (BV), and vaginitis caused by fungal organisms (vulvovaginal candidiasis, VVC) or T. vaginalis are difficult because of overlapping signs and symptoms along with the possibility of dual infections. All entities are typically considered clinically and diagnostically at the same time.
BV is not an infection per se, but a disorder attributed to overgrowth of mixed vaginal flora including multiple anaerobes, Gardnerella vaginalis, and Mycoplasma spp. in addition to the loss of the normal lactobacilli. The change in flora results in an increase in volatile amines and increased vaginal pH (alkaline >4.5) that produces the typical “fishy” odor when 10% potassium hydroxide (KOH) is added to a smear of the vaginal discharge.
The condition is most commonly seen in sexually active individuals; in those patients where BV is identified, the recommendation is to screen for other STIs. Thus the presence of BV in a child is not indicative of sexual abuse.7
Vulvovaginal candidiasis (VVC) is the second most common cause of vaginal symptoms in females presenting to health care providers; 20% to 30% of females have Candida spp. as part of their vaginal flora and seed urogenital areas from the gastrointestinal tract and perianal area.
4. A review of guidelines to distinguish between gastric and pulmonary placement of nasogastric tubes
Measuring aspirate pH
As shown in Table6, geographical location has a strong influence on recommendations for use of the pH method. For example, guidelines from the U.K. (II, VI and IX) favor the pH method as first-line testing for NG tube placement. In contrast, guidelines from the U.S. (I, V and XI) favor pH testing only as a precursor to radiographic confirmation of correct tube location. Regardless of geographical location, pediatric guidelines are more likely to favor the pH method for first-line testing, presumably to avoid risk for radiation injury from x-rays.
5. Advantages of pH-testing
There are important advantages to use of the pH method:
- Theoretical basis.A distinct difference is typically present between the pH of fasting gastric juice and pulmonary aspirates (tracheobronchial secretions and pleural fluid).
- Compared to radiography, pH-testing is cost-effective. For example, a typical pH test strip costs less than 25 cents.10 In contrast, an x-ray may cost several hundred dollars.
- Time to results.Once an aspirate has been obtained from the NG tube, it can be applied to a test strip or paper and results are available within one or two minutes.
- The pH method can be used in home settings as well as in acute and long-term care facilities.
Question
1. What is the purpose of a pH strip?
pH strips are a cheap and relatively accurate way of measuring the pH of any liquid, in our case urine. A strip of filter paper is soaked with different pH indicators (more on that later), allowed to dry and voila: pH strips. Most common pH strips are designed to test urine, water and saliva
2. What does pH mean on a test strip?
The strips in use read from pH of 0 to pH of 14 in 1 unit increments. pH strip color changes coincide with a numeric pH interpretation: Red/Orange to Yellow/Green (pH 1-6) = Acid Green (pH 7) = Neutral Dark Green/Blue (pH 8-14) = Alkaline.
What is urine on pH strip?
How the Test is Performed. After you provide a urine sample, it is tested right away. The health care provider uses a dipstick made with a color-sensitive pad. The color on the dipstick tells the provider the level of acid in your urine
3. How do you read pH strip results?
Dip the strip into the solution and then remove it after a few seconds. Shake off any excess liquid and then compare the color of the strip to the color chart provided by the manufacturer. The color of the strip will indicate the pH level of the solution.
4. What is a good pH level?
The U.S. Environmental Protection Agency recommends that the pH level of water sources should be at a pH measurement level between 6.5 to 8.5 on a scale that ranges from 0 to 14. The best pH of drinking water sits right in the middle at a 7.
5. What does pH positive mean?
Ph+ ALL is a blood cancer caused by a genetic mutation.
This mutation creates an abnormal chromosome known as the Philadelphia (Ph) chromosome. This chromosome produces a blood protein in which two genes—BCR and ABL1—bond together to form BCR-ABL1.