New Safety Precautions for HPLC: Handling Extreme Heat, Lightning, and Heavy Rain

In addition to making people uncomfortable, high temperatures can also affect our HPLC systems. Have you noticed that summer is a season when HPLC problems frequently occur? Let's take a look at some important precautions for the summer.

01 Lightning Protection for HPLC Systems in Summer

Summer thunderstorms are frequent, and low-lying clouds can discharge electricity to the ground. Direct lightning strikes and induced lightning are the two main forms of lightning hazards in laboratories. Direct lightning occurs when a charged cloud (thundercloud) rapidly discharges to a building, other objects, the ground, or a lightning protection device. Induced lightning, on the other hand, is caused by strong electromagnetic field changes generated by a lightning current, which induces high voltage and poses a greater threat to electronic equipment in the laboratory.

Therefore, it is essential to implement lightning protection measures during the design and construction phase of the laboratory.

External Lightning Protection Measures

Laboratory buildings fall under the second category of lightning protection structures. External lightning protection measures mainly consist of lightning rods or lightning belts, down conductors, and grounding systems.

Internal Lightning Protection Measures

While external lightning protection measures are effective and economical for preventing direct lightning strikes, they are not sufficient for protecting precision instruments and equipment within the laboratory. The real culprits behind the damage to precision instruments are the overvoltage caused by induced lightning and the intrusion of lightning surges.

In laboratory settings, precision instruments are particularly vulnerable to induced lightning through various channels such as power lines, signal lines, grounding lines, and enclosure ports exposed to direct lightning strikes, which create indoor magnetic fields. Therefore, internal lightning protection cannot rely on just one or two advanced devices. A step-by-step protection approach and comprehensive protection strategy are needed to minimize the risks posed by induced lightning.

02 HPLC Rain Protection in Summer

Can a liquid chromatograph get rained on while staying in the lab? Check out the image below!

Laboratory fume hoods are generally designed like this.

Metal equipment, regardless of its form, needs special attention during heavy rain. There’s a real-life example of a user who experienced a costly mishap when their sophisticated GC-MS/MS was "immersed" in heavy rain, resulting in substantial repair costs. So, remember to keep a close eye on your laboratory instruments during thunderstorms and take rain protection measures seriously.

To prevent rainwater backflow, we recommend:

Install wind and rain shields on the exhaust ducts, or design the exhaust outlet to direct airflow downward.
After work during heavy rain , adjust the angle of the fume hood's intake to prevent the instrument from being directly beneath the intake.

03 Preventing Blockages and Leaks

Blockages and leaks often go hand in hand, especially during the summer. Here’s what to watch out for:

1）Prevent Microbial Growth

Summer conditions are ideal for the growth of microbes and algae. Prolonged use in such conditions can damage solvent filters, tubing, degassers, proportioning valves, and chromatographic columns. This not only incurs high repair costs but also delays experiments. For channels running pure water, pure salt solutions, or low-percentage organic phases, rinse the channels with organic solvents and store them properly after experiments. During extended breaks when instruments are not in use, replace aqueous phase tubing with organic phase to prevent microbial growth.

2）Correct Use of Mobile Phases

Prepare Mobile Phases Fresh: Always prepare mobile phases right before use, label them clearly with expiration dates and preparation dates.
Use Chromatographic-Grade Reagents: Filter aqueous mobile phases with a 0.2 μm membrane and organic phases with a 0.45 μm membrane. Ensure compatibility between solvents and membranes.
Gradients and Solvent Mixing: During gradient experiments, ensure the miscibility of solvents during gradient changes. Do not switch directly between immiscible solvents; use isopropanol as a transition solvent.
Buffer Solutions: When using buffer salts in mobile phases, avoid direct flushing with high organic phases to prevent salt precipitation. Clean the pump piston rod regularly.
Isocratic Experiments: For isocratic experiments with pure salt phases, such as the phosphocreatine sodium project in Ch.P, it is advisable to refrigerate prepared mobile phases and replace them with new ones at room temperature every half day. For other isocratic conditions, pre-mix aqueous and organic phases before use, rather than mixing them online with a pump proportioning valve.

3) Proper Use of Acetonitrile

Acetonitrile is prone to polymerization, which occurs slowly at room temperature and can be accelerated by strong summer sunlight. This polymer can deposit on the inlet check valve's jewel, affecting pump accuracy. To manage acetonitrile:

Use Fresh Acetonitrile: Pour acetonitrile as needed and replace it frequently.
Store in Amber Bottles: Use brown bottles to avoid direct sunlight exposure.
Keep Acetonitrile Clean: Avoid dust and impurities, as they can serve as nuclei for polymer formation.
Cleaning: If the valve is clogged with acetonitrile polymers, clean the tubing with hot water and isopropanol, or use ultrasonic treatment to dissolve the polymers.

04 Solvent Evaporation Prevention

During the summer, high temperatures increase the evaporation of most solvents. Don’t underestimate solvent evaporation—have you noticed an increase in RSD compared to before? For those who leave containers uncovered, not only do you face greater experimental deviation, but the solvents evaporating into the air also pose significant health risks.

You need a solution to safeguard your experimental results and laboratory environment. A special bottle cap with a one-way valve allows only clean air to enter the bottle, preventing organic solvents from evaporating into the air while balancing the internal and external pressure of the solvent bottle. Additionally, ensure that waste containers are equipped with traps and alarms to maintain a cleaner and healthier laboratory.

Test Item: Airtightness Test

Sample Description: Glass Bottle + Safety Cap

Testing Method: GB/T 17344-1998

Testing Conditions:

Pressure: 2 kPa
Test Duration: 5 minutes
Laboratory Environmental Conditions: 23 ± 2°C, 50 ± 5% RH

Test Conclusion: No bubbles observed

Connected waste liquid collection device