A validated liquid chromatography/tandem mass spectrometry method for 4,4′‐methylenedianiline quantitation in human urine as a measure of 4,4′‐methylene diphenyl diisocyanate exposure

Abstract

Rationale 4,4′‐Methylene diphenyl diisocyanate (MDI) is a highly reactive isocyanate used in the production of polyurethanes. Workers exposed to these products may develop sensitization to the diisocyanate compounds, leading to occupational asthma. Quantifying MDI levels is necessary to ensure workplace safety. MDI is metabolized by acetylation and/or conjugation to macromolecules for excretion into urine. All metabolites can be chemically hydrolyzed to form the free diamine 4,4′‐methylenedianiline (MDA) as a urinary biomarker of MDI exposure. Current methods involve long sample preparation, or have been designed using costly automation. There is therefore a need to develop a new practical method for assessing exposure to MDI. Methods Urine samples were acidified and heated to form MDA, followed by neutralization and liquid–liquid extraction. Extracts were separated by reversed‐phase chromatography on a HSS T3 column followed by analysis on a triple quadrupole mass spectrometer in multiple reaction monitoring (MRM) mode. Results 13C15N‐MDA was selected as the internal standard (IS) of choice following an investigation of internal standard stability. The hydrolysis efficiency, forming free MDA from conjugated metabolites in vivo, was evaluated using 4,4′‐methylenebis(acetanilide) spiked into urine and complete hydrolysis occurred after 1 h. A dynamic range of 5 to 500 nM was achieved, and was useful for monitoring MDI exposure considering the biological guidance value (BGV) of 10 μg/L (~50 nM) proposed by the German Research Foundation (DFG). The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.8 and 2.7 nM, respectively. The intra‐day and inter‐day precisions were 4.33% and 4.27%, respectively. Finally, the method was tested with inter‐laboratory samples from the German External Quality Assessment Scheme (G‐EQUAS) program and the results submitted were all within the allowable tolerance range. Conclusions A practical and validated method for the analysis of small‐ to medium‐sized batches of samples has been developed for the biological monitoring of MDI exposure in human urine.

Rapid quantification of tenofovir in umbilical cord plasma and amniotic fluid in hepatitis B mono‐infected pregnant women during labor by ultra‐performance liquid chromatography/tandem mass spectrometry

“…Thus, its retention behavior on general reversed‐phase chromatography columns is weak. The HSS T3 bonded phase was reported to be more suitable to retain and separate small water‐soluble polar organic compounds . In our pre‐test, TFV exhibited better retention behavior and peak shape in the HSS T3 column than in the BEH C18 column.…”

Contaminants of emerging concern in urine: a review of analytical methods for determining diisocyanates, benzotriazoles, benzothiazoles, 4-methylbenzylidene camphor, isothiazolinones, fragrances, and non-phthalate plasticizers

“…This required derivatization using 4-(1-pyrene)butanoyl chloride (PBC) (Sun et al 2018 ). Compared to the methods using negative chemical ionization (NCI) set-ups, such as GC NCI-SIM (Mirmohammadi et al 2013 ), UPLC (Bhandari et al 2016 ; Lépine et al 2020 , 2019a ), and nano-UPLC with MRM (Robbins et al 2018 ) were described for the detection of MDA. This approach yields ten times lower LOQ (0.001 ng/mL) and does require any complex sample preparation procedures (offline-SPE).…”

“…Dried and reconstituted in 200 μL of ACN (0.1% FA) Nano-UPLC: Type not reported Column: Waters Symmetry C18 (100 mm × 100 μm, 3 μm) Mobile phases: A (0.1% FA/W), B (0.1% FA/ACN), flow: 0.6 μL/min Gradient elution: 95–10% A, 17 min ESI(+)-MS2-MRM: Type not reported 0.03 (LOD) Robbins et al ( 2018 ) MDI MDA LLE: 190 μL of urine deconjugated with sulphuric acid (100 °C, 60 min) and neutralized and extracted with MePh. Dried and reconstituted in 200 μL of water UPLC: Waters Acquity Column: Waters Acquity HSS T3 (50 mm × 2.1 mm, 1.8 μm) Mobile phases: A (0.1% ammonium acetate/W), B(0.1% ammonium acetate/MeOH), flow 0.6 mL/min Gradient elution: 5% B, 0.5 min, 5–90%, 3 min, 90%, 1 min ESI(+)-MS2-MRM: Waters Xevo Triple Quadrupole 0.535 Lépine et al ( 2019a ) MDI MDA LLE: 1 mL of urine deconjugated with sulphuric acid (100 °C, 16 h), neutralized and extracted with MePh. Dried and derivatized by HFBA.…”

Study on the determination of some diamine in urine by LC-MS/MS

“…Để chuyển dạng tồn tại monoacetyl hoặc diacetyl về cùng diamin tương ứng cần phải thủy phân mẫu với HCl với thời gian ủ mẫu phù hợp. Sau đó, có thể xác định đồng thời các diamin bằng các phương pháp như GC-MS, LC-MS/MS [13][14][15][16][17][18]. Trong đó, phương pháp LC-MS/MS được sử dụng phổ biến do đáp ứng được độ nhạy, độ chính xác, cũng như thời gian phân tích phù hợp.…”

“…phân tử của HDA, MDA, IPDA, số khối của các ion mẹ tương ứng với từng chất phân tích, chúng đều có dạng là [M+H] + , mỗi chất thu được 2 ion con. Kết quả này cũng phù hợp với một số nghiên cứu trước đây[13,16].…”