A 7-Point Lab Supply Checklist: Corning Products, pH Meter Calibration, and the Accessories You Forget

Running a lab means managing a hundred small dependencies. The consumables you order today become the data you get next week. If you are the person doing that ordering, the fastest way to keep the lab moving is a checklist that covers both the everyday supplies and the maintenance items that only matter when they break.

I'm the office administrator for a 60-person R&D company. I manage the purchasing workflow for lab consumables and equipment accessories—or rather, I manage the orders and the vendors; the lab managers approve the specs. We spend roughly $140,000 a year on these purchases, maybe $150,000 if you count rush shipping. Here is the 7-point checklist I have built over the past five years.

1. Check the Corning catalog for the exact product number

Corning products are everywhere in our lab: centrifuge tubes, serological pipettes, vacuum filters, glassware. The Corning catalog is the reference source because product numbers are unique to each configuration. I learned this the hard way in March 2023. I ordered 10 cases of what I thought were 50 mL Corning centrifuge tubes. The number was off by one digit—we received 15 mL conical tubes. By the time anyone noticed, five bags had already been opened. We could not return them, and the replacement cost $340 plus a nine-day delay.

That mistake changed how I order. I do not search by product name anymore. I search the Corning catalog or ask the lab manager for the number off the box. The catalog shows whether a tube is sterile or non-sterile, packaged with or without a cap, and which cap style fits. I write that number down before I create the purchase order.

2. Copy the catalog number into the PO notes

Catalog numbers look boring. They matter. A purchase order that says 'Corning 15 mL tubes' can be interpreted in several ways. A purchase order that says 'Corning 430791' cannot. I also attach the product PDF to the PO. After I hit submit on one filter order, I immediately wondered whether I had chosen 0.22 µm instead of 0.45 µm. I had not saved the PDF. I spent the next hour finding the catalog page again. Now the PDF goes with the order, and the critical spec goes in the notes field.

3. Add the Mettler Toledo pH meter calibration to the quarterly order

A pH meter does not look like a consumable, but it depends on them. Our meter is from Mettler Toledo, and the calibration buffers are orderable items. I am not a calibration engineer, so I cannot speak to the instrument internals. What I can tell you from the operations side is the routine our lab staff follows from the manual.

Here is the 'how to calibrate pH meter Mettler Toledo' version we use with our InLab probes:

1. Rinse the probe with deionized water and gently shake off excess liquid.
2. Place the probe in a fresh aliquot of pH 7.00 buffer solution.
3. Wait for the reading to stabilize, then enter calibration mode on the meter.
4. Rinse the probe again with deionized water.
5. Repeat the process with pH 4.01 buffer, or pH 10.01 if that is closer to your sample range.
6. Accept the calibration and confirm the displayed slope is within the range stated in the manual.
7. Return the probe to its storage solution, for Mettler Toledo probes that is usually 3 M KCl.

One internal note: do not reuse buffer for calibration. Once a buffer bottle is opened, write the date on it. If it is past the date in your SOP, toss it. According to the Mettler Toledo manual, calibration should be done with fresh buffers and the probe should be rinsed between buffers. A 30-second habit saves a day of rerunning samples.

4. Put the caliper battery cover on the order before it disappears

A digital caliper is a $300 measurement tool. The battery cover is a much smaller cost. When the cover clip snaps, many people leave the caliper in the drawer and buy a new one. We had a good caliper sitting useless for a month because no one thought to order a caliper battery cover.

Now I keep a 'small replacement parts' line item on every quarterly order. It includes caliper battery covers, pH buffer, probe storage solution, and spare fuses. Not glamorous, but it prevents the moment when someone says 'I need this right now' and the lead time is five days.

5. Use the C5 thermal camera for proactive equipment checks

One more item that is not a Corning product: the C5 thermal camera. It belongs in the same procurement calendar because it is part of preventive maintenance for lab equipment. We scan electrical panels, motor housings, and incubators twice a year. A hot breaker or a loose connection shows up before it forces an unplanned shutdown.

The C5 thermal camera is small enough to keep in a drawer, which means it can get lost like a caliper battery cover. The checklist includes checking the camera battery, charger, and memory card before the scan day. Otherwise, you have a toolbox full of good intentions and a dead camera.

6. Consolidate the order and verify the unit of measure

We order Corning products through our main distributor and add consumables such as pH buffers and replacement parts to the same batch whenever possible. When I compared our rush orders and standard orders side by side for one year, I saw we were paying about 30% more for shipping on items that could have been included in the previous order. Now I batch purchases at the end of each month and keep a small inventory of high-use items.

The other check is the unit of measure. I once approved an order where the unit was cases instead of bags. The invoice was $400 more than expected. The supplier corrected it, but the conversation could have been avoided by matching the catalog number to the packing quantity in the Corning catalog. A 90-second check at the PO stage saves a 40-minute phone call and a return label.

7. Keep a backup for anything that stops a procedure

If a filter is bad and the experiment is scheduled for tomorrow, no one cares whose fault it is. They care if the filter is in the lab. We keep one extra pack of the Corning vacuum filters we use most often, plus one spare caliper battery cover and an extra bottle of pH 7.00 buffer. The inventory cost is small. The cost of a failed experiment is not.

What I still forget, and why the checklist works

Even with this checklist, I still make mistakes. Most happen because I assume a catalog number from a previous PO is still current. Corning sometimes repackages products, and catalog numbers can change, so I try to verify before ordering. I also do not fully understand why our lab goes through calibration buffer faster than the usage rate suggests. My best guess is open bottles are left unsealed at the bench. If someone has solved that, I would love to hear it.

The purpose of the checklist is not perfection. It is to catch the small things before they become the 'we cannot do the experiment' email. The simpler the check, the easier it is to do every time.