Analysis of Mannitol in Human Plasma

Mannitol is an osmotic diuretic that is physiologically inactive in humans and is found naturally in fruits and vegetables as a sugar or sugar alcohol. Mannitol raises the osmolality of blood plasma, allowing more water to move from tissues including the brain and cerebrospinal fluid into interstitial fluid and plasma (1).

analysis of mannitol in human plasma

Fig.1 3D Model of Mannitol

Mannitol can be used to:

  • Reduce Inter-cranial Pressure

Mannitol is administered intravenously and becomes a new solute in the plasma. Thus, increasing the tonicity of the plasma, which will pull water into the intravascular space from the brain parenchyma. The water will then be excreted through the kidneys.

  • Reduce Intra-ocular Pressure

Due to an increase in the plasma's tonicity by mannitol, water from the vitreous humous of the eye is drawn out to the intravascular space.  Finally, the water and mannitol will be excreted by the kidneys. The intraocular pressure is reduced as the vitreous humor’s water content decreases.

  • Promote Diuresis in Acute Renal Failure

Intravenous mannitol is sometimes given to those who have acute renal failure. Even in acute renal failure, the kidneys are responsible for a large portion of mannitol excretion. As mannitol is expelled, it attracts water, boosting the patient’s water output and assisting in the prevention or treatment of fluid overload caused by oliguria in acute renal failure.

  • Excrete Toxic Materials

Mannitol can be used to promote the excretion of harmful chemicals, substances, and medications, similar to how it is used to treat oliguria in acute renal failure.

  • Prevent Intradyalytic Hypotension

Hemodialysis patients frequently experience intradialytic hypotension and dialysis disequilibrium symptoms. The reason for this is a decrease in intradialytic osmolality. By increasing serum osmolality, mannitol can help prevent intradialytic hypotension.


Mannitol is administered intravenously when used for medical purposes (2). Mannitol
is available in a variety of quantities, ranging from 5% mannitol (5 gm mannitol
dissolved in 100 mL solution) to 25% mannitol (25 gm of mannitol dissolved in 100 mL
of fluid) (2). The amount of mannitol administered depends on the type of condition
that is being treated (2).

  • Increased Intercranial Pressure – dosages range from 0.25 g/kg to 2 g/kg
  • Increased Intraocular Pressure – dosages range from 0.25 g/kg to 2g/kg
  • Oliguria treatment – 0.2 g/kg
  • Excretion of toxic materials – 0.25 g/kg to 2 g/kg

Side effects

  • Heart failure
  • The movement of free water into the intravascular region might cause or worsen electrolyte imbalances. Hyponatremia, hypokalemia, and hypocalcemia are some of the electrolyte disorders that might occur.
  • Worsen cerebral edema. Frequent mannitol doses can cause mannitol to penetrate the blood-brain barrier, worsening cerebral edema because the mannitol that has leeched into the brain attracts water into the brain rather than out of it.
  • Dehydration due to diuresis


We have analyzed mannitol in human plasma. Using our HPLC instruments (Fig. 2), we have determined our LLOQ and ULOQ to be 7.5 and 1500 µg/ml, respectively.

HPLC mannitol analysis

Fig. 2 HPLC

To book our instruments please contact us here.


1. National Library of Medicine. Mannitol. (Internet) (Cited on Aug 2021) Available from:

2. StatPearls. Mannitol. (Internet) (Cited on Aug 2021) Available from:

Our HPLC Training Courses

Looking for A HPLC training COURSE?

High Performance Liquid Chromatography is a powerful analytical tool. We offer HPLC training courses which will give you all the skills needed to master the HPLC instrument.

Who is this course for?

HPLC training

Fig.1 Our HPLC system

HPLC training is for any person (no previous experience needed) who is looking to improve their laboratory skills or learn how to master the HPLC instrument. Depending on your previous experience we will prepare a tailored training to cover everything you may need to know.

Both HPLC training courses are taught on a 1 to 1 basis (maximum 2 people) so that you can take the most out of this training and have plenty of time to adapt to the instrument. We focus on giving you a complete and practical experience, hence by the end of the training, you will feel confident to run by yourself your own set of samples on the instrument.

Course Options

We offer two HPLC courses:

  • 3 Day HPLC Training
  • 1 Day HPLC Refresher Course

The 3 day course covers all the HPLC basics, standard laboratory training, sample preparation, method development and data analysis. It is the perfect choice for someone that may want to learn how to set and run HPLC to improve their analytical skills. This is a complete course that aims to teach you all the fundamentals you need to run your own samples.

The 1 day course covers HPLC basics and method development, however it is subject to the trainee’s previous experience. This course is advised to someone that already has some experience with HPLC and wishes to remind themselves about HPLC basics/method development or is looking for advice on method development for their own research project.

Structure of the 3 Day Course

  • Day 1 – Essential reading & standard laboratory training
  • Day 2 – Sample preparations & method development
  • Dat 3 – Method development (continuation) & data analysis

At the end of the course, there is a Q&A with our manager, you can clarify any questions you might have.

How to book

Fill out the form in the contact us page, or if you prefer you can email us or call us directly. Please click here to book your HPLC training course!





Amlodipine in Veterinary Practice

Amlodipine has been used to treat high blood pressure in humans, but it has now been approved for veterinary practice. It is given to cats and dogs to treat hypertension and other associated diseases.

About Amlodipine

This drug is classified as a calcium channel blocker. The heart and arteries contract more forcefully when calcium is present, thus calcium channel blockers relax and widen blood arteries by inhibiting calcium. This effect will lower the blood pressure which prevents heart diseases, heart attacks and strokes.

amlodipine in veterinary practice

Fig.1 Chemical Structure of Amlodipine

Side effects

Like all medicines, amlodipine can have side effects. In animals, common side effects include vomiting, lack of appetite, diarrhea and sleepiness (1). Serious side effects such as severe weakness, changes in urination, abnormal bleeding or rapid heart rate are rare, but can also occur (1).

Hypertension in Cats

Hypertension in cats is a moderately frequent and possibly fatal condition. The most prevalent kind of hypertension in cats is secondary hypertension, which is caused by an underlying systemic condition that impairs the body’s regulatory mechanisms responsible for maintaining normal blood pressure (2). Among these conditions, chronic kidney disease and hyperthyroidism are the most common (2).

Injury to organs can happen due to hypertension. The most prevalent target organ injury found in cats with hypertension is ocular disorders, which can range from retinal detachment resulting in blindness to more subtle indications like hemorrhage or swelling in the back of the eye (2).

Hence, not only can amlodipine treat hypertension, but it can also be given to cats to prevent damage to kidneys, heart, brain, and eyes.

Analysis of Amlodipine in Feline Plasma

Using our HPLC system and LC-MS, we have examined amlodipine in feline plasma. The LLOQ and ULOQ were set for the method as 0.5 ng/ml and 100ng/ml respectively for Amlodipine. The Limit of Detection was calculated as -0.001 ng/ml in feline plasma.


  1. Rania Gollakner. Amlodipine. (Internet) VCA. (cited on 2021 Jul) Available from:
  2. Cornell Feline Health Center. Hypertension: Feline hypertension. (Internet) College of Veterinary Medicine. (updated 2021; cited on 2021 Jul) Available from:
Bio-Analysis at the One Nucleus Bio Wednesday 2019

Bio-Wednesday One Nucleus hosted by LBIC at the RVC

We were delighted to be asked to join the panel last night at the One Nucleus event hosted by LBIC at the RVC.


The topic, ‘Staffing the 21st Century Life Sciences R&D Industry.’ bio-analysis HPLC and LCMS

As an employer of several graduates, undergraduates and summer placements in our 5 years of business, we were interested to be part of the discussion and hear other people’s point of view.

We have found the quality of students coming through to be excellent and a real asset to us. In a business like ours they receive a very hands on and varied approach to the commercial world of bio-science.  (A hugely different experience from starting out in a Big Pharma Organisation!)

Discussion topics resonated around what the future looks like for graduates and post graduates; what skills employers and recruitment professionals are looking for: risk takers, lateral thinkers, commercial acumen; what could be taught, what should be taught and the changing foot print of career paths.

For a business like ours, people skills are essential, along with self motivation and common sense.


We pride ourselves in offering an excellent technical and customer service.  Our HPLC and LC-MS training can be combined with method development and bespoke consultancy to help advance your Research and Development.  Once trained, clients can come back and use the equipment to continue their research projects.

As a business and an employer, we have a lot to offer so please get in touch.


Bio-Analysis at the On Nucleus Bio-Weds - HPLC and LCMS




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deltaDOT’s High Performance Capillary Electrophoresis

The Bio-Analysis Centre offers High Performance (label free) Capillary Electrophoresis (HPCE) system from deltaDOT to its clients.

Whilst electrophoresis is the process during which ions undergo movement in a fluid or gel under the influence of an electric field, capillary electrophoresis is a technique that separates these ions based on their electrophoretic mobility with the use of an applied voltage. This mobility is dependent on the atom’s radius, the charge of the molecule, and the molecule’s viscosity. The rate at which the charged particle moves is directly proportional to the applied electric field – as the field strength increases the mobility increases also.

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method development

Chromatographic analysis – An Intern’s Perspective

Chromatographic analysis is often an indispensable technique for a life scientist.

The gadgetry and the skills required, for the successful application of such techniques, are less so common. Having spent the summer months of 2017, working for the Bio Analysis Centre, I have been a very keen observer of the company’s modus operandi. I have been most impressed by the assembly of systems, developed and maintained by the laboratory manager, Dr. Hyde. This framework for the BAC ensures the smooth running of the services it provides.

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Triple-Quad MS Used to Confirm Food Safety

As the global population continues to grow exponentially the demand for food becomes ever more pressing. In order to supply this mounting demand, the world’s crop production must increase through optimised methods, fertilisers, agrochemicals and pesticides. Nonetheless, with strict regulations regarding contaminants including pesticides, mycotoxins and heavy metals the manufacturing of food and drinks must be monitored vigilantly. Analytical instrumentation technologies and methods on a mass spectrometer alongside gas chromatography allow this food safety promise to be guaranteed.

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An Introduction to Solid Phase Extraction (SPE)

Analytical scientists utilise a range of sample preparation tools to aid their method development, how they approach this challenge can significantly impact their success.

Solid Phase Extraction (SPE) is a type of sample preparation technology that uses solid particle and chromatographic packing material to chemically separate the different components of a sample.

Samples are usually in a liquid state and are run through stationary phase particles in a cartridge. The chromatographic bed can be used to selectively remove interferences to ensure subsequent analytical testing is more successful.


Liquid-Solid Phase Extraction carries the same basic principles of liquid chromatography used in HPLC, but for different reasons. In SPE, chromatography is used to prepare a sample prior to analytical testing.


Samples used in SPE can originate from a wide range of sources. They can be biological fluids (eg. Plasma, saliva, urine), food products (eg. Grain and meat), environmental samples (eg. Water, air, soil), pharmaceuticals, beverages or industrial products.


There are numerous benefits to using SPE:


  • The procedure can simplify a complex sample matrix and aid in purifying the compound. If there are a large number of interfering constituents or substances in the sample matrix, it makes analysis extremely difficult.
  • SPE can reduce ion suppression or enhancement in MS applications. With an appropriate method this effect will be minimised by cleaning the interferences from the compound, resulting in a more accurate reported value.
  • It has the ability to fractionate a sample matrix to allow analysis of compounds by class. If a sample contains many compounds, separating them by class can be useful so that further analysis can be carried out much more efficiently.
  • SPE allows better analysis of trace concentration of very low level compounds. The chromatographic packing material has retention capabilities which allow the ability to trace concentrate. This would be very difficult with other sample preparation techniques.