Automatic methods for the determination of

Mineral oil hydrocarbons (MOSH/MOAH) by online LC/GC-FID coupling

Methods to improve precision data, increase efficiency

and improve user-friendliness

Standardization- Methods

EN 16995: 2017-08 Vegetable oils and foodstuff on basis of vegetable oils ‘Determination of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) with online HPLC-GC-FID analysis’

LOQ= 10 mg / kg

ISO 17780 Animal and vegetable fats and oils—Determination of saturated aliphatic hydrocarbons in vegetable oils Offline method

LOQ= 50 mg /kg

DGF C-VI 22 (20)

Published December 2020

"Mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) with online coupled LC-GC-FID method for low limits of determination" - German Society for Fat Science (DGF) - Division Analysis and Quality Assurance – - developed over the last years - Cowork of 13 laboratories

LOQ= 1,0 mg / kg

Procedure Samples with high content of biogenic, long-chain alkanes and interfering unsaturated compounds

Ethanol-hexane distribution

Saponification

ALOX Clean-up Clean-up

Online - HPLC-GC-FID

Epoxidation

Online-HPLC-GC-FID

MOSH fraction MOAH fraction

Procedure Samples with low content of biogenic, long-chain alkanes and interfering unsaturated compounds

Ethanol-hexane ditstribution

Saponification

Clean-up

Epoxidation

Online - HPLC-GC-FID

Examples: Coconut fat Linseed oil Butter

MOSH + MOAH fraction

Interference removal

• Blank value minimization

• Lower limits of quantification

• Higher accuracy of analyses

• Time saving procedures

Automated Sample Preparation steps

Sample Preparation

• Online ALOX-Cleanup

• Epoxidation

• MOSH depletion

1st aliquot of sample:

Manual AlOx-Cleanup

Evaporation of the eluate

Injection 1

Analysis MOSH

2nd aliquot of sample

Injection 2

Analysis MOAH

Manuell ALOX

Injection with

online ALOX-Cleanup

Analysis MOSH and MOAH

Online ALOX

Only one injection

for the analysis of

MOSH and MOAH

Spiked vegetable oil (Sunflower spiked with lubricating oil)

MOSH

MOSH

AlO

x-C

lean

up

6.2 ppm

ALOX Clean Up

Pump for

AlOx-Cleanup AlOx-column

Pump for HPLC

separation Silica gel column

UV-detector GC with

2-channel setup

Only one injection

for the analysis of

MOSH and MOAH

ALOX Clean Up Scheme

Alkanes Reference C10-C50

Alkane Reference C10-C50 after autom. ALOX

ISTD‘s MOSH after autom.- ALOX

C20

C20

C50

C50

Cholestane

Examples autom. ALOX Clean Up

Tea: 15,9 mg/kg MOSH after ALOX Clean up

ISTD‘s

ISTD‘s

Examples autom. ALOX Clean Up

• After sample 133, the ratio between

cholestane and CYCY changes.

Exchange of the column is pending

• The cleanup works even though the ratio

changes.

The results are still valid

Precision data:

20-fold measurement of a sunflower oil

(according to the CEN- EN 16995:2017)

Mean = 3.6 mg/kg MOSH

Relative standard deviation = 8.8%

When will the ALOX column be replaced?

MOAH

Natural olefins

• E.g. squalene, carotenoids, sterenes

• Sometimes high concentration in food

• Leads to highly overloaded peaks in GC

• Detection of small mineral oil impurities almost impossible

Separation by HPLC not possible due to polarity differences

• Requires chemical modification

Increase of polarity

Spiked vegetable oil (Olive oil spiked with lubricating oil)

Automatic epoxidation

Workflow: Ethanolic epoxidation

Sample extract after Clean Up step = 1 mL n-hexane

Add 1 mL ethanolic m-CPBA-solution

Epoxidate sample 20 min at 40 °C

Add 500 µL ethanol and 2 mL sodiumthiosulfate/potassium carbonate solution for decomposition of the excess mCPBA

Shake for 1 min at 750 Rpm

Transfer hexane phase into Vial ( with spatula tip of Sodium sulfate)

Inject into online-HPLC/GC

Process could be completly automated

MOAH

2.8 ppm MOAH

MOAH

Spiked vegetable oil (Sunflower spiked with lubricating oil)

Ep

oxid

atio

n

Examples Epoxidation

without Epoxidation

Total MOAH= 5,4 mg/kg

Olive oil

Ep

oxid

atio

n

Examples Epoxidation

• Developed by cooperation of Axel Semrau and Funke Analytic Consult

• Required for the analysis of cosmetic samples

• Results in an LOD of 30 mg/kg MOAH for cosmetic samples

Sample Preparation for MOSH: MOSH-Depletion

Weigh in aliquots

(z.B. 500 mg)

Extract with hexane

(60 °C)

Dilution for MOAH:

1:50 + ISTD

Dilution for MOSH:

1:1000 + ISTD

Analysis LC-GC-FID

Procedure for:

• Raw materials for cosmetics

• Cosmetic products

• Main care products

• Skin cream

MOSH-Depletion

MOSH-Depletion

Position 1: Enrichment MOAH + Reduction MOSH

• Flow over precolumn

towards waste

MOSH-Depletion

• Backflushing Precolumn

• Direction Backflush Valve

Position 2: Analysis of MOAH fraction

MOSH-Depletion

Not all data systems can handle this kind of

data

How is the data analyzed?

New software for MOSH/MOAH calculations

Advanced integration software for UCM-humps

Chrolibri Software

• All steps can be performed in one product • Integration of the Hump

• Integration of ISTD's

• Identification

• Integration and subtraction of sharp peaks

• Quantification

• Reporting

• No copy & paste necessary

Advanced integration software for UCM-humps

Minimization of errors

Time saving

Chrolibri Software - Features

Easy change of channels

Chrolibri Software - Overview

Updated calculation of the results

Various views and specification options

Direct integration and subtraction of interfering peaks

Chrolibri Software - Overview

Results table

Chrolibri Software - Overview

Chrolibri Software – Export options

• Customized reports with HTML

• Direct export as PDF

• LIMS export

Advanced integration software for UCM-humps

Minimization of errors

Time saving

Chrolibri Software – Export options

Thank you for your attention!

Phone: +49 (0)5454 9532 Mobile: +49 (0)176 51246147 Email: tf@funke-ac.de Web: www.funke-ac.de

Thomas Funke Postdamm 178 48477 Hörstel Germany

Funke Analytic Consult