purity grades of lab reagents - labicom.cz · producer assigns the grade of chemicals at its own...

PURITY GRADES OF LAB REAGENTS –HOW TO CHOOSE THE RIGHT GRADE?

Dr. Katarzyna Pokajewicz

May 2018

Honeywell Confidential - © 2017 by Honeywell International Inc. All rights reserved.

Honeywell Research Chemicals

200 year of

experiencein producing chemicals:

Seelze, Germany

Muskegon, USA

Worldwide known and

leading brands:

Fluka

Riedel de Haen

Burdick&Jackson

Hydranal

A global portfolioof more than 6,000

references for analytical

and chemistry labs


www.lab-honeywell.com

http://www.lab-honeywell.com/

© 2018 by Honeywell International Inc. All rights reserved.

4


Honeywell Confidential - © 2018 by Honeywell International Inc. All rights

reserved.

Laboratory reagent

A single chemical or a mixture of chemicals dedicated for laboratory use

Lab reagent should have:

• Guaranteed quality parameters: specified purity and specified impurities issued on CoA

• Proper package and label• Defined shelf life/expiration date


5

Impurities in lab reagents

• chemical

• physical

• biological

• primary

• secondary


6



reserved.

Latin name Abbreviation National name Abbreviation

purum speciale pur. spec. zvláště čistý zv. č.

purissimum puriss. chemicky čistý ch. č.

pro analysis p. a. pro analýzu p. a.

purum pur. čistý č.

technicum techn. technicky tech.

Raising purity

Common names for purity grade of chemicals in Eastern bloc

Purity of lab reagent

content of proper chemical expressed in % after deducting impurities

Based on standards from Comecon (COuncil for Mutual ECONomic assistance)


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reserved.


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reserved.

No common law or obligatory standards

Producer assigns the grade of chemicals at its own preference

Internationally used descriptions of grades:

tech., techn.

pure, purumC.P. (chemically pure)

extra pure

puriss. Laboratory grade

reagent grade

GR (guaranteed reagent)

Pro analysis

Synthesis grade

Comparing chemicals only on the grade name is impossible

Crud.


9



reserved.

• European Pharmacopoeia (Ph. Eur.)

• United States Pharmacopeia (USP)

• ACS specifications

International standards

11-th edition contains monographies

for over 500 reagents


10

„ACS reagent” or „ACS grade” is a guarantee that reagent

meets some minimal parameters written in ACS specification.

ACS grade is currently the worldwide standard for laboratory

use.


11

Honeywell’s contribution to ACS (11th edition)


12

Special grades

• For spectroscopy UV-VIS

• For liquid chromatography (HPLC, LC-MS)

• For gas chromatography

• For inorganic trace analysis (ASA, ICP)

• For semiconductors (VLSI, ULSI grade)

• For DNA/RNA/peptide synthesis

• Anhydrous

• For molecular biology (PCR)

• For cell culture

Key impurities

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Application

HPLC

• Solid particles

• UV-VIS absorbing

synthesis

UV-VIS

spectroscopy

LC-MS

HPLC

GC

• Solid particles and non-

volatiles

• Alkali ions

• Suppressing ionization

• Water

• Volatile solvents (HS)

• Non-volatile

• Metallic cations and inorganic anions

AAS/ICP



14

For spectroscopy UV/VIS

Requirements for the method:

• UV/VIS absorbing contaminants – as low as possible

• Detailed specifications for absorbance

Advantage:

• More sensitivity and lower detection limit

• Reproducible spectrum


15

For liquid chromatography (HPLC)

Requirements for the method:

• High purity

• Degassed mobile phase

• No solid particles (filter 0.2 um)

• Low absorbance (UV-VIS detection)

• Low fluorescence (fluorescence detection)

• Low metal content and non-volatile residue (MS

detection, ICP-MS)

No particles

Degassed mobile

phase

Advantage:

• Longer column and instrument durability

• Repeatable analyses

• Lower detection limit

• Better spectra


16

Impurities absorbing UV-VIS light:

• Raising baseline in gradient elution mode (baseline drift)

UV-VIS detection

• Less sensitivity and higher uncertainty of the method

UV Abs.

Retention time

Isocratic elution

Gradient elution

Gradient elution –

contaminated solvent

HPLC grade

Reagent grade

Method: HPLC Chromatograms at 200 nm for acetonitrile. A Waters 2695 HPLC with a B&J OD5 (C-

18) (#9575) 25cm X 4.6mm, 5um column was used for this experiment. The flow rate was 1mL/min.

Gradient water/acetonitrile.


17

Comparison of acetonitrile: reagent grade and HPLC grade

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29

Lot

UV

Ab

so

rba

nc

e a

t 2

25

nm

(a

bs

. u

nit

s)

-0,01

0,49

0,99

190 240 290 340

UV

Ab

so

rba

nce

(ab

s)

Wavelength (nm)

• Higher UV absorbance in range 195-240 nm indicates organic impurities

• Low and consistent UV absorbance results for different batches of HPLC grade- enable achieving higher

sensitivity and good repeatability


18

MS detection

Very high purity is required and very low impurities like:


• non-volatiles

• alkali metal ions and other compounds impairing ionization

Impurities can:

• destroy equipment

• suppress/alter ionization in the source

• create adducts


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(… and many metal ions)


2020

LC-MS Ultra CHROMASOLV

LC-MS CHROMASOLV

CHROMASOLV Plus

CHROMASOLV gradient

CHROMASOLV

Purity grades of HPLC solvents from Honeywell

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Borosilicate glass bottles

197.9713

325.1941

451.3073

532.9422

648.9335

698.9277

792.9043

847.8578 909.8569 1014.8415

LCMS Ultra UVMSneg_RD1_01_3235.d: -MS, 3.0-9.1min #(270-809), -Constant Bkgrnd

219.9947

248.9723

325.2004

355.9741

384.9540

520.9360 648.9327

698.9393

858.8914 906.8939 983.8583 1035.8551

Chrom Gradient Grade UVMSneg_RD1_04_3232.d: -MS, 3.0-9.0min #(270-807), -Constant Bkgrnd0

200

400

600

800

Intens.

0

200

400

600

800

200 400 600 800 1000 1200 m/z

Sodium formate adducts

LC-MS Ultra grade

(borosilicate glass)

Gradient grade

(amber glass)

Alkali ions leaching from the glass

Chromasolv LC-MS Ultra

22

Modern techniques – quality really matters!

Problem:

• UV mode – both solvents gives the same result and the same sensitivity

• MS mode – invisible to UV impurities impair ionization and as a result sensitivity is worse

3.5 3.6 3.7 3.8 3.9 4.0 4.1 Time [min]0.0

0.5

1.0

1.5

5x10

Intens.

Vitamin D3 Test_BB1_03_6848.d: BPC 49.0000-1801.0000 +All MS Vitamin D3 Test_BB1_02_6847.d: BPC 49.0000-1801.0000 +All MS

Vitamin D3 Test_BB1_01_6849.d: BPC 49.0000-1801.0000 +All MS Vitamin D3 Test_BB1_02_6850.d: BPC 49.0000-1801.0000 +All MS

Vitamin D3 Test SpS_BB1_06_6857.d: BPC 49.0000-1801.0000 +All MS Vitamin D3 Test SpS_BB1_05_6856.d: BPC 49.0000-1801.0000 +All MS

Vitamin D3 Test SpS_BB1_04_6855.d: BPC 49.0000-1801.0000 +All MS Vitamin D3 Test SpS_BB1_03_6854.d: BPC 49.0000-1801.0000 +All MS

LC-MS Ultra Acetonitrile (magenta)

Competitor R (orange)

CH3

H3C

H

H

CH2

HO

Vitamin D3

3.5 3.6 3.7 3.8 3.9 4.0 Time [min]

0

5

10

15

Intens.

Vitamin D3 Test_BB1_03_6848.d: UV Chromatogram, 254 nm Vitamin D3 Test_BB1_02_6847.d: UV Chromatogram, 254 nm Vitamin D3 Test_BB1_01_6849.d: UV Chromatogram, 254 nm

Vitamin D3 Test_BB1_02_6850.d: UV Chromatogram, 254 nm Vitamin D3 Test SpS_BB1_06_6857.d: UV Chromatogram, 254 nm Vitamin D3 Test SpS_BB1_05_6856.d: UV Chromatogram, 254 nm

Vitamin D3 Test SpS_BB1_04_6855.d: UV Chromatogram, 254 nm

LC-MS Ultra Acetonitrile (blue)Competitor R (green)

CH3

H3C

H

H

CH2

HO

Vitamin D3

Advances in modern instrumentation and analytical chemistry force us to create new grades of reagents with higher

purity and tougher specifications

ICP-MS detection

• For analyses by LC-ICP-MS

• Solvent line TraceSELECT™

• Extremely pure – the group combines both features of HPLC and ICP

grades

• Metal traces at ppb level or lower

23

For speciation analysis

For GC (gas chromatography)

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• Mobile phase is gas, not liquid mixture of solvents. Different problems with contaminants.

• Reagents are used for sample preparation and for injection.

• Thus solvents' impurities are then the constituents of the sample. They are not delivered continuously as in HPLC.

• Impurities are undergoing chromatographic separation on GC column and their peaks are visible on chromatograms.

• Impurities can be multiply enriched during sample preparation

• If retention time of impurities is close to of our analytes – problem!

Direct

injection

GC

Headspace

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GC grade solvents (for pesticide residue analysis)

• Developed specifically for residue analysis of pesticides

• Suitable for the analysis of polychlorinated biphenyls (PCBs)

• Tested for suitability in pesticide residue analysis against 5 ng/L

lindane or heptachlor

• Very low content of non-volatile matter (max. 0.0005 %) –

improves column lifetime

• Meet requirements for both extraction steps and for GC injection

• Consistently high purity for wide range of GC applications

Distinguishing

GC grade

Comparison of methanol

reagent grade and GC grade

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100

200

300

400

500

0 5 10 15 20 25

Inte

ns

ity (

EC

D C

ou

nts

)

Time (min)

100

200

300

400

500

0 5 10 15 20 25

Inte

ns

ity (

EC

D C

ou

nts

)

Time (min)

Method: 200mL of methanol was concentrated (400x) and exchanged into hexane. The data was

obtained on an Agilent 6890N GC with an ECD detector and a Restek Rtx-5 30 meter column. Sample

injection = 5 microliters. The initial oven temperature was held at 200C for 15 minutes then increased by

10C/min until 250C, then held for 10 minutes.

Note the solvent front interference and many large contamination

peaks in standard grade methanol are absent in the purified

methanol.

Common impurities in methanol:

2-butanone (MEK), 3-pentanone, N, N-dimethyl acetamide, and

2,3-butanedione.

These impurities are not detected by GC-MS in purified methanol.

Inorganic trace analysis

TraceSELECT line

• Purified by subboiling distillation

• Up to 80 cation and anion impurities tested

• High quality package:

HDPE for TraceSELECT

PFA (fluoropolymer) bottles forTraceSELECT Ultra

Requirements for AAS/ICP reagents :

• High purity versus metals and ionic traces

• High quality packaging from proper organic polymer

Lot-to-lot variation

0

10

20

30

40

50

60

70

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

Lot

Wate

r C

on

cen

trati

on

(p

pm

)

Lower grades can be very good against

one parameter in specific lot, but we do

not have guarantee it will repeated in

next batch.

Only higher grades with tighter

specification on specific parameter give

us such guarantee and lot-to lot

consistency.

Reagent grade and HPLC grade acetonitrile

Packaging

Safe storing and handling

Ensures product stability Isolation from light, air

InertNot dissolving the package material and its contaminants

(bottles, drums, caps, septa)

Ensures special functionFixanal

VOLPAC

Moisture absorption

High quality package is very important for high

quality reagents and significant part of

production cost

General rules - summary

• There are different grades of lab reagents but there is one universal and the best one for all kinds of

applications.

• Each technique has different requirements. Application test in product specification confirms that product was

tested for this technique.

• The higher purity, tighter specification as well as unusual package– the higher the cost of the lab reagent.

• When choosing lab reagent one needs to analyze specification for parameters important in the application.

There is no need to overpay irrelevant parameters.

• The lower the grade– the higher the lot-to-lot variability and less repeatability in results*. Technical grades can

be used in fact therefore for teaching classes and for some limited applications.

• In research/analytical work one needs to choose at least: reagent grade, pro analysis, puriss. or ACS grade.

• Only ACS grade is really comparable – this one is good to choose for scientific work - to enhance reproducibility

of published studies.

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purity grades of lab reagents - labicom.cz · producer assigns the grade of chemicals at its own...

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