In my previous role at a pharmaceutical lab, I frequently needed to quantify unknown acid concentrations for formulation work.

I was tasked with accurately determining the molarity of an unknown hydrochloric acid sample using titration.

I prepared a standardized sodium hydroxide solution, calibrated the burette, added phenolphthalein indicator to the acid sample, and performed a slow titration until the endpoint turned faint pink. I recorded the volume of NaOH used and calculated the concentration using the stoichiometric relationship.

The calculated concentration was within 0.5% of the certified value, allowing the formulation batch to proceed on schedule without rework.

During a method development project for pesticide residues, I needed to select the optimal chromatographic technique.

Determine whether GC or HPLC would provide better sensitivity and selectivity for the target analytes.

I evaluated the volatility and thermal stability of the compounds. Volatile, thermally stable pesticides were suited for GC with a flame ionization detector, while non‑volatile, polar metabolites required HPLC with a UV‑Vis detector. I also considered sample preparation time and column availability.

The final method used GC for the parent pesticides, achieving a 10‑fold lower detection limit, and HPLC for the metabolites, ensuring complete coverage of the residue profile.

In the quality control lab, I needed to quantify a dye concentration in a water sample using UV‑Vis spectroscopy.

Create a reliable calibration curve covering the expected concentration range.

I prepared a series of standard solutions (0, 2, 4, 6, 8 mg/L) using a certified stock, measured absorbance at the dye’s λmax, plotted absorbance versus concentration, and performed linear regression. I verified linearity (R² > 0.998), checked for stray light, and ran duplicate measurements. I also included a blank and performed a recovery test on a spiked sample.

The assay showed a linear response with <2% deviation, and the recovery of the spiked sample was 98%, confirming the curve’s reliability for routine analysis.

At my previous employer, the lab was preparing for an OSHA inspection and needed to update the CHP.

Assist the safety officer in reviewing and implementing the CHP components to meet regulatory standards.

I audited existing SOPs, identified gaps in PPE usage, and updated the chemical inventory database. I conducted training sessions on proper labeling, MSDS access, and spill response. I also helped develop a waste segregation protocol and posted emergency contact information prominently.

The updated CHP passed the OSHA audit with no citations, and employee compliance with PPE increased from 78% to 96% within three months.

During a routine transfer, a 2 L drum of acetone tipped, spilling onto the bench and floor.

Safely contain and clean the spill while preventing fire hazards and exposure.

I immediately activated the emergency alarm, evacuated non‑essential personnel, and donned flame‑resistant PPE and a respirator. Using a Class B fire extinguisher, I doused the area to suppress vapors. I then applied an absorbent spill kit, collected the saturated material into a labeled hazardous waste container, and sealed it. Finally, I documented the incident and reported to the safety officer.

The spill was contained without ignition, no injuries occurred, and the area was cleared for normal work within 30 minutes. The incident report led to a revised drum‑handling SOP.

Our lab received a bulk shipment of new reagents lacking proper GHS labels.

Implement GHS-compliant labeling for all incoming chemicals.

I cross‑referenced each chemical with its SDS to identify hazard pictograms, signal words, and precautionary statements. I printed labels using the lab’s GHS label template, affixed them to containers, and updated the electronic inventory with the hazard codes. I also conducted a brief refresher for staff on reading GHS symbols.

All chemicals were correctly labeled within two days, and a subsequent internal audit confirmed 100% GHS compliance.

During an HPLC analysis of a pharmaceutical intermediate, the target peak exhibited pronounced tailing, affecting quantitation.

Identify and correct the cause of peak tailing to restore method performance.

I first checked the column for contamination and performed a back‑flush. I examined mobile phase pH and ionic strength, adjusting the buffer to the recommended range. I inspected the injector for leaks and replaced the septum. Finally, I ran a system suitability test with a standard mixture to verify peak symmetry.

After adjusting the pH and cleaning the column, peak tailing reduced from a tailing factor of 2.3 to 1.1, meeting acceptance criteria and allowing accurate reporting of results.

Our analytical lab was receiving increasing sample volumes for water quality testing, leading to a backlog of up to 48 hours.

Reduce the average turnaround time to under 24 hours while maintaining accreditation standards.

I mapped the existing workflow and identified bottlenecks at sample preparation and data entry. I introduced a parallel processing station for filtration, cross‑trained technicians to operate both stations, and implemented a LIMS‑driven auto‑import of instrument data. I also set up a daily huddle to prioritize urgent samples.

Turnaround time dropped to an average of 20 hours, backlog was eliminated, and audit reviewers noted no deviation in data integrity.

During a synthesis, the balance log showed 5.00 g of reagent X, but the reaction required only 4.50 g, and the remaining 0.50 g was unaccounted for.

Determine the source of the discrepancy and correct the inventory record.

I re‑weighed the remaining reagent in the original container, verified the balance calibration, and checked the lab notebook for any undocumented transfers. I discovered that 0.30 g had been transferred to a secondary vial for a parallel experiment without being logged. I updated the inventory, recorded the transfer in the notebook, and performed a balance calibration check.

The inventory was corrected, the balance was confirmed accurate, and a new SOP was introduced requiring immediate logging of any reagent split, preventing future discrepancies.

The production manager needed to understand why a batch of polymer failed quality specifications due to impurity levels detected by GC‑MS.

Translate the analytical findings into actionable information for the manager.

I prepared a concise report using visual aids: a bar chart comparing impurity percentages against limits, and a brief narrative explaining the source of the impurity. I held a 15‑minute meeting, avoided technical jargon, and highlighted the impact on product performance and regulatory compliance. I also suggested corrective actions, such as adjusting the purification step.

The manager approved the corrective action plan within a day, and the next batch met specifications, preventing a potential production delay.

A batch of specialty chemicals failed the final purity test, causing a delay in shipment to a key client.

Work with production, QA, and supply chain to identify root cause and implement a fix.

I organized a root‑cause analysis meeting, facilitated data sharing from the analytical lab, production logs, and raw material certificates. Using the 5‑Why method, we traced the issue to a contaminated solvent batch. I coordinated with procurement to quarantine the solvent, updated the SOP for solvent verification, and communicated the corrective plan to the client.

The defect was eliminated in subsequent batches, on‑time delivery was restored, and the client expressed confidence in our corrective actions.

On a busy shift, I received three urgent sample requests: a stability test, a release test for a new batch, and a regulatory compliance check.

Determine the order of execution to meet all deadlines without compromising data quality.

I assessed each task’s deadline, impact on production, and regulatory urgency. I communicated with the lab supervisor to confirm the release test had the highest priority, scheduled the stability test next, and allocated the compliance check to a colleague with overlapping expertise. I also updated the LIMS to reflect the revised schedule and monitored progress closely.

All three analyses were completed within their required windows, the batch was released on time, and the compliance check passed without delay.