Essays on analytical chemistry, methods, and careers in industry.

All essays

1. Conditioning your SPME fibre: why two vendors disagree, and which advice to follow

   Supelco's older fibre data sheet says longer conditioning will not hurt the fibre; Agilent's newer guide says do not condition longer than necessary because fibre life drops at high temperature. What each says, how to condition and clean a fibre, and the temperature and solvent limits to respect.

   SPME

   Oct 2026

   5 min

2. SPME without an isotope-labelled internal standard is a guess

   Why quantitative SPME depends on an internal standard added before extraction, ideally isotope-labelled: what EPA Method 8272 does and why, how it handles calibration, blanks and carryover, and what to do when no labelled standard exists.

   SPME

   Oct 2026

   5 min

3. Equilibrium, pre-equilibrium or kinetic: how SPME is calibrated, and why it matters

   SPME extracts only part of the analyte, so it has to be calibrated. The main approaches explained from the SPME literature and my own published work: traditional external and internal standards, equilibrium calibration, diffusion-based calibration, and kinetic calibration with a pre-loaded standard.

   SPME

   Oct 2026

   6 min

4. SPME troubleshooting: carryover, broken fibres, broad peaks and poor precision

   A symptom-by-symptom guide to the problems SPME users report, with the causes and fixes from vendor documents, a published carryover study and the SPME literature: ghost peaks and carryover, fibres that break, broad or tailing peaks, low recovery and poor repeatability.

   SPME

   Oct 2026

   6 min

5. Will your Nutrition Facts table pass CFIA's test? How the 80/120 rule works

   How the Canadian Food Inspection Agency checks a Nutrition Facts table in the lab: twelve units in three composites, the 80% and 120% limits, the 50% rule for each composite, the stricter rule for added vitamins and minerals, and why a single-unit result can mislead.

   Industry

   Oct 2026

   5 min

6. The front-of-pack "high in" symbol: the lab numbers behind it

   Canada's front-of-package nutrition symbol became mandatory on January 1, 2026. The thresholds (15%, 10% and 30% of the Daily Value), which quantity of food they apply to, how rounding is handled, which foods are exempt, and what the lab result has to show.

   Industry

   Oct 2026

   5 min

7. Canada's PFAS objective: 30 ng/L for the sum of 25, and why a more sensitive lab can report a higher sum

   What Health Canada's 2024 drinking-water objective for PFAS asks the lab to measure: which 25 compounds, how non-detects and reporting limits enter the sum, why EPA Method 533 is recommended, and how it compares with the EU and US limits.

   LC-MS

   Oct 2026

   7 min

8. How to get ISO 17025 accreditation through CALA: nine steps, and the rules people miss

   The path to ISO/IEC 17025 accreditation for a Canadian testing lab through CALA, in order, from CALA's own documents: what to submit and when, how the assessment and findings work, the 90-day response window, proficiency testing, and the six-month rule for every method on the scope.

   Validation

   Oct 2026

   5 min

9. Nitrosamine false positives: when the method makes the nitrosamine

   How a nitrosamine test can create the result it reports: nitrite in the diluent, heat in a GC inlet, DMF next to NDMA, contaminated reagents. And the experiments that show whether a positive is real.

   LC-MS

   Oct 2026

   9 min

10. Unpaid students in your lab: what Ontario law says, and three legal ways to do it

    Can a small Ontario lab take students to work for free in exchange for experience and a certificate? What the Employment Standards Act guide says about interns and trainees, when unpaid placements are allowed, the safety duties that still apply, and three funded or legal alternatives.

    Industry

    Oct 2026

    5 min

11. What a Health Canada inspector writes up in a QC lab

    Health Canada publishes the GMP observations its inspectors classify as critical, major and other. A chromatographer's reading of the ones that apply to a QC or contract testing lab, grouped by what they mean at the bench.

    Industry

    Sep 2026

    6 min

12. logP vs logD vs pKa: which one your assay actually needs

    Three numbers that get used interchangeably and answer different questions. What each one is, how they are related, and which of them your method development or your discovery screen actually depends on.

    Method development

    Sep 2026

    5 min

13. Perpendicular drop or tangent skim: how to integrate overlapping HPLC peaks

    Which integration rule to use for partly resolved peaks, shoulders and small peaks on a tail: perpendicular drop, tangent or exponential skim, or valley-to-valley. With the size-ratio rule of thumb, what the 2026 simulation data show, and how to set it in Empower.

    HPLC

    Sep 2026

    10 min

14. Dwell volume: why a gradient method changes when you move it to another HPLC

    Dwell volume, also called gradient delay volume, is the volume between the mixing point and the column head. It decides how late your gradient actually starts. How to measure it in under half an hour and what to do about the difference.

    HPLC

    Sep 2026

    13 min

15. What ISO 17025 accreditation costs a small Canadian lab

    CALA's published fees for ISO/IEC 17025 accreditation, worked through for a lab with five methods, and the costs the fee schedule does not show: the standard, proficiency testing, reference materials, calibration, uncertainty work and staff time.

    Validation

    Aug 2026

    5 min

16. Your syringe filter is part of your method: what it takes out and what it adds

    Syringe filters can adsorb analyte and leach contaminants. What the data show for nylon, PTFE, PES, RC and MCE membranes, why the first millilitre is the worst, and how to run a filter study against a centrifuged sample.

    HPLC

    Aug 2026

    6 min

17. Synthetic curcumin passes HPLC: how adulterated botanicals fool identity tests

    Why a turmeric extract spiked with synthetic curcumin can pass HPTLC, HPLC-UV, HPLC-MS, IR and NMR, how labs detect it (curcuminoid ratios, synthesis byproducts, carbon-14), and what this means for identity testing of botanical natural health products and supplements.

    HPLC

    Aug 2026

    5 min

18. GTA labs have an LC-MS problem that hiring will not fix

    Toronto-area labs have idle LC-MS instruments and methods only one person understands. Why hiring won't fix the chromatography skills gap, and what will.

    Industry

    Jul 2026

    6 min

19. Real-time stability for natural health products: what GMP version 4 asks for

    Health Canada's NHP GMP guide version 4, in force since March 4, 2026, requires a completed stability study for every NHP marketed in Canada, real-time studies to confirm any extrapolated shelf life, and expiry dates counted from the date of manufacture. What that means for the testing calendar, accelerated data, bulk hold times and out-of-trend results.

    Validation

    Jul 2026

    5 min

20. Resolution is not sensitivity. Choosing between a QTOF and a triple quadrupole

    High resolution and high sensitivity are different things. A QTOF identifies what you cannot name. A triple quadrupole quantifies what you already know is there. Picking the wrong one means you cannot reach your limit, however good your method is.

    LC-MS

    Jul 2026

    5 min

21. Finished product specifications no longer go to Health Canada. Why your lab results matter more, not less

    Since June 2026, natural health product licence applicants no longer submit finished product specifications with Class II and III applications. What changed, what GMP still requires, the tolerances an NHP is tested against, and what a licence holder should check in its own specifications.

    Industry

    Jul 2026

    5 min

22. Trial injections: why "just checking the system" is a major GMP observation

    Why regulators treat trial injections of samples as a data integrity problem, what a 2026 FDA warning letter found, what Health Canada's GUI-0023 says, and how to condition and check an HPLC properly before a GMP run.

    HPLC

    Jul 2026

    5 min

23. Measuring logD by HPLC: how I profiled new molecules at a CRO without the shake-flask

    Chromatographic logD profiles a molecule's lipophilicity from calibrated HPLC retention, faster and on less sample than shake-flask. How it works, from the bench.

    HPLC

    Jun 2026

    5 min

24. The literature pKa isn't the one running your method. How to measure the one that is

    The literature pKa is aqueous; the apparent pKa in your mobile phase governs retention. How to measure it from retention versus pH, and read it off the first derivative.

    HPLC

    Jun 2026

    6 min

25. System suitability test (SST) in HPLC: parameters and failures

    An HPLC system suitability test (SST) checks the system with a known standard before samples run. What each parameter means, and where to look when one fails.

    HPLC

    Jun 2026

    11 min

26. Protein precipitation leaves the phospholipids behind: how to see them in LC-MS and remove them

    Why protein precipitation of plasma leaves phospholipids that suppress LC-MS signal, how to see them with the m/z 184 phosphocholine ion, and what SPE, supported liquid extraction and phospholipid-removal plates change, including the recovery losses an independent lab found.

    LC-MS

    Jun 2026

    6 min

27. Total THC by GC or HPLC: why the number on a cannabis oil can be wrong

    Why GC-MS without derivatisation under-reports total THC and CBD, what the 0.877 factor assumes, how a single extraction leaves 6–9% behind, and what an Ontario study found when it tested 30 legal cannabis oils against their labels.

    Method development

    Jun 2026

    6 min

28. Purity angle vs purity threshold: what PDA peak purity tells you, and what it can't

    Purity angle vs purity threshold in Empower PDA peak purity: what each means, why peaks above 1 AU fail, and why a pass does not prove a peak is pure.

    HPLC

    Jun 2026

    8 min

29. Matrix effect in LC-MS: how to measure it, and when an internal standard is enough

    How to find and measure matrix effect in LC-MS/MS with post-column infusion and the post-extraction spike, the three formulas labs use for the same number, and what a stable-isotope internal standard corrects.

    LC-MS

    May 2026

    10 min

30. How analytical chemistry postdocs can rewrite their resumes for pharma, CRO and biotech roles

    Problem-led PhD resume/CV isn't the problem. The language is. Here's how to translate your postdoc work into industry signals that get interview calls

    Career

    May 2026

    12 min

31. Why chemical logic beats instrument time in cosmetic method development

    A Ph.D. chemist breaks down how chemical logic, not trial and error, cuts LC-MS method development time for cosmetic peptide testing.

    LC-MS

    May 2026

    10 min

32. Your Ph.D. made you industry-adjacent not industry-ready

    Your PhD trained you for novelty. Industry wants reliability. What I learned crossing that gap in 14 years of analytical chemistry.

    Career

    May 2026

    6 min

33. LC-MS method development is risk mitigation. Most labs treat it like a recipe

    A failed method costs you a month, sometimes two. Method development is risk mitigation, and most labs skip the work that proves it.

    HPLC

    May 2026

    10 min

34. What industry actually wants from analytical chemists

    Your degree taught you to run a method. Industry hires people who can own one. How to show that before your first interview.

    Career

    May 2026

    6 min