— Writing
All essays
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
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
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
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
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
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
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
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
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
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
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
9 min
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
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
4 min
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
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
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
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
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
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
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
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
What an HPLC system suitability test (SST) checks, and where to look first when %RSD, tailing, resolution, plates or retention fails.
HPLC
Jun 2026
11 min
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
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
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
How Empower's PDA peak purity works, what purity angle and purity threshold mean, why peaks above 1 AU can fail, how to set the noise interval and solvent angle, and why a passing result does not prove a peak is pure.
HPLC
Jun 2026
8 min
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
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
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
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
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
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