Preservation & Holding Times


Holding times should be from the documented time a sample was collected, not based on midnight of the last day. For example, if a semivolatile water sample (with a holding time of 7 days) was taken at 8:30 am on Tuesday, October 15, 2019, then the laboratory can extract that sample at any time up until 8:30 am on Tuesday, October 22, 2019 and be considered within the method's holding time.

Holding times are distinctions in the methods to try to reduce the effect of degradation on the results due to analyte decomposition, reaction, evaporation and any number of other effects of time on a sample matrix. However, a line has to be drawn somewhere for unacceptable losses and the method's holding time represents the best data available as to when the analysis is still completely valid. If an exact sample collection time is known, then the exact time should be used in calculating the holding times. If the collection time is recorded to the hour, the holding time should be interpreted to the hour. If the collection time is recorded to the hours and minutes, the holding time should be interpreted to the hours and minutes.

Ideally, laboratories should try to do the required preparation steps (i.e., extraction, digestion, etc.) in advance of the hold time's expiration so as to avoid hold time problems.

All chain of custody forms and sample acceptance forms will indicate the temperature of samples upon receipt.  The sample acceptance form will indicate if thermal preservation requirements for the analysis request have not been met.  This information is transferred during log-in to the LIMS record.  Metals analysis for all matrices including low level mercury, PCB analysis of a chemical waste, samples requiring radiological analyses, and soil samples requiring pH only analysis do not require thermal preservation.  Samples received for these analyses have met thermal preservation requirements even when received above 6oC.

METALS

Parameter
Method
Hold Time
Preservative
Container
ID
Total Metals (excluding Hg) 6010/200.7 6020/200.8 6 months HNO3 to pH<2 1-500cc P J
Dissolved Metals (excluding Hg) 6010/200.7 6020/200.8 6 months Field Filtered, HNO3 to pH<2 1-500cc P I
Chromium, hexavalent 7196A 3500Cr,B 24 hours* Cool 4oC 1-500cc P F
Mercury 7470A/245.1 28 days HNO3 to pH<2 1-500cc P J
* If preserved with NaOH, the holding time is extended to 28 days.

INORGANIC NON-METALS

Parameter
Method
Hold Time
Preservative
Container
ID
Acidity, Total 2310B 14 Days 4°C 1-500cc P L
Alkalinity, Total (CaCO3) 2320B 14 Days 4°C 1-500cc P L
Ammonia (as N) 350.1R2.0 4500NH3, D 28 Days H2SO4, 4°C 1-250cc P or AG H
BOD, 5 Day 5210B 48 Hours 4°C 1-500cc P L
Bromide 300.0 28 Days 4°C 1-500cc P L
CBOD, 5 Day 5210B 48 Hours 4°C 1-500cc P L
Chloride 4500Cl, E 4500Cl, C 28 Days 4°C 1-500cc P L
Chlorine Residual, Free 4500Cl, G Immed. 4°C 1-500cc P L
Chlorine Residual, Total 4500Cl, G Immed. 4°C 1-500cc P L
Chlorophyll a SM10200H 2 Days 4°C 1-1L AG N
Chromium, Hexavalent 3500Cr,B 7196A 28 Days* NaOH,4°C 1-250cc P F
COD 5220D 28 Days H2SO4, 4°C 1-250cc P or AG H
Coliform, Fecal COLILERT 7 Hours Sterile Bact P
Coliform, Total SM9222B 1 Day Sterile Bact P
Color, true 2120B 2 Days 4°C 1-960cc P L
Conductivity 2510B 28 Days 4°C 1-500cc P L
Cyanate 4500CN, L 10 Days NaOH,4°C 1-250cc P F
Cyanide, Amenable 4500CN,C,G 14 Days NaOH,4°C 1-250cc P F
Cyanide, Total 335.4R1.0 4500CN,C,E 9010B/9014 14 Days NaOH,4°C 1-250cc P F
Cyanide, WAD 4500CN-I,E 14 Days NaOH,4°C 1-250cc P F
Dissolved Oxygen 4500O,G Immed. 4°C 1-500cc P L
Fluoride 4500F,C 28 Days 4°C 1-500cc P L
Hardness, Total (as CaCO3) 2340C 6 Months 4°C 1-960cc P L
Hydrolyzable Phosphorus (as P) 4500P,B,E 28 Days H2SO4, 4°C 1-250cc P or AG H
Iron Bacteria SM9222B 1 Day Sterile Bact P
Iron, Ferrous 3500Fe. B   4°C 1-500cc P L
MBAS SM5540C 48 Hours None 1-250cc P L1
Nitrate (as N) 353.2R2.0 28 Days H2SO4, 4°C 1-250cc P or AG H
Nitrate + Nitrite (as N) 4500NO3, E 28 Days H2SO4, 4°C 1-250cc P or AG H
Nitrite (as N) 4500NO2,B 48 Hours 4°C 1-500cc P L
Oil & Grease 1664A 28 Days HCL, 4°C 1-1L AG M
Organic and Volatile Acids HPLC-UV 14 Days 4°C 1-500cc P L
Organic Phosphorus (as P) 4500P, A 28 Days H2SO4, 4°C 1-250cc P or AG H
Orthophosphate (as P) 4500P,E 48 Hours 4°C 1-500cc P L
pH @ 25°C 4500H+,B 9040B Immed. 4°C 1-500cc P L
Phenols 9066 420.4R1.0 28 Days H2SO4, 4°C 1-250mL AG H
Phosphate (as PO4) 4500P,B,E 28 Days H2SO4, 4°C 1-250cc P or AG H
Phosphorus (as P) 4500P,B,E 28 Days H2SO4, 4°C 1-250cc P or AG H
Settable Organic Solids 2540F, b 7 Days 4°C 1-500cc P L
Settable Solids 2540F, b 48 Hours 4°C 1-500cc P L
Silica (as SiO2) 4500SiO2,C 28 Days 4°C 1-500cc P L
Soluble COD 5220D 28 Days None 1-500cc P L
Sulfate 375.2R2.0 4500S04,E 28 Days 4°C 1-500cc P L
Sulfide 4500S2C,D 7 Days NaOH/ZnAc 1-250cc P O
Sulfite 4500SO3,B Immed. 4°C 1-500cc P L
Threshold Odor 2150B Immed. 4°C 1-960cc P L
TIC 5310C 28 Days No Treat 1-250mL AG D1
TOC 5310C 9060 28 Days H2SO4, 4°C 1-250mL AG H
Total Carbon 5310C 28 Days H2SO4, 4°C 1-250mL AG H
Total Dissolved Solids 2540C 7 Days 4°C 1-500cc P L
Total Kjeldahl Nitrogen (TKN) 351.2R2.0 28 Days H2SO4, 4°C 1-250cc P or AG H
Total Non-Volatile Suspnd Solids 2540E 7 Days 4°C 1-500cc P L
Total Solids 2540B 7 Days 4°C 1-500cc P L
Total Suspended Solids 2540D 7 Days 4°C 1-500cc P L
Total Volatile Solids 2540E 7 Days 4°C 1-500cc P L
Total Volatile Suspended Solids 2540E 7 Days 4°C 1-500cc P L
TOX 9020B 14 Days H2SO4, 4°C 1-500mL AG E1
TPH (SGT-HEM) 1664A 28 Days HCL, 4°C 1-1L AG M
Turbidity 2130B 48 Hours 4°C 1-500cc P L
Tests for parameters with identical Container IDs may be taken from the same container.
KEY to container types: P = Plastic; AG = Amber Glass
* If unpreserved the Hexavalent chromium HT is 24 hours.

ORGANIC PARAMETERS

Parameter
Method
Hold Time
Preservative
Container
EDB/DBCP (Method 8011) 8011 28 Days 4°C 2-40mL Vials
Pesticides/PCBs 8081A/8082 7 Days Extraction 40 Days Analysis 4°C1 1-1L AG
Pesticides 608/8081A 7 Days Extraction 40 Days Analysis 4°C 1-1L AG
Polychlorinated biphenyls (PCBs) 8082 None 4°C 1-1L AG
Carbamate Pesticides 531.1R3.1 28 Days 4°C 2-40mL Vials
Endothall 548.1R1.0 7 Days 4°C 1-125mL AG
Non-Halogenated Organic Compounds 8015B 7 Days Extraction 40 Days Analysis 4°C 2-40mL Vials
Organophosphorus Pesticides 8141A   4°C 1-1L AG
Dioxin, High Resolution 8290 30 Days Extraction 45 Days Analysis 4°C 2-1L AG
Dioxin, Low Resolution 8280 30 Days Extraction 45 Days Analysis 4°C 2-1L AG
Formaldehyde 8315A 30 Days 4°C 1-125mL AG
Herbicides 8321A 7 Days Extraction 40 Days Analysis 4°C1 1-1L AG
Dissolved Gases RSK175/D1946 14 Days HCL, 4°C 2-40mL Vials
Trihalomethanes (THMs) 524.2 14 Days HCL, 4°C 3-40mL Vials
Semi-Volatile Compounds (SVOCs) 625/8270C 7 Days Extraction 40 Days Analysis 4°C1 1-1L AG
Polynuclear Aromatic Hydrocarbons 8270C 7 Days Extraction 40 Days Analysis 4°C1 1-1L AG
TOC 5310C/9060 28 Days H2SO4, 4°C 1-250mL AG
TOX 9020B 14 Days H2SO4, 4°C 1-500mL AG
TPH 8015B 7 Days Extraction 40 Days Analysis 4°C 1-1L AG
Volatile Organic Compounds 624/8260B 14 Days HCL, 4°C1 2-40mL Vials
1The indicated parameters will require Na2S2O3 if free chlorine is present.
KEY to container types: Vials = zero-headspace 40mL vial; AG = Amber Glass


SAMPLE BOTTLE PRESERVATIVES AND HOLDING TIMES FOR SOILS & SEDIMENT SAMPLES


METALS

Parameter
Hold Time
Preservative
Container
General, total 6 Months None 4 or 8 oz. Wide-mouth Glass Jar
Chromium, hexavalent 30 Days to Extraction 7 Days to Analysis None 4 or 8 oz. Wide-mouth Glass Jar
Mercury 28 Days None 4 or 8 oz. Wide-mouth Glass Jar

ORGANIC PARAMETERS

Parameter
Hold Time
Preservative
Container
Pesticides and PCBs 14 Days to Extraction 40 Days to Analysis Unpreserved
Cool 4o C
4 or 8 oz. Wide-mouth Glass Jar
GC/MS Semivolatiles (including PNAs) 14 Days to Extraction 40 Days to Analysis Unpreserved Cool 4o C 4 or 8 oz. Wide-mouth Glass Jar
Volatile Organics 14 Days Method 5035 sampling Cool 4o C 4 or 8 oz. Wide-mouth Glass Jar  plus Method 5035 Vials
PCBs (Only) None Cool 4o C 4 or 8 oz. Wide-mouth Glass Jar



Contact Us

First Environmental Laboratories, Inc.
1600 Shore Road # D
Naperville, IL 60140
P: (630) 778-1200
F: (630) 778-1233
firstinfo@firstenv.com
Monday - Friday, 8:00am - 5:00PM

Testimonials

  • Generic placeholder image
    Paulette Amaya

    I went to First Environmental Labs to get a lead test for my home day care. Everyone is very polite and explained everything step by step. I am very glad I found this lab😀

  • Generic placeholder image
    Tyler P

    Friendly and efficient staff.

Our Vision is to become the premier environmental testing laboratory in the Midwest. We intend to achieve this goal by:

  • Providing Superior levels of customer service
  • Being the employer of choice in the industry
  • Providing the highest level of data quality in the business
  • Establishing a relationship with our customers and employees built on trust and mutual respect
  • Fostering a sense of enjoyment and satisfaction in all of our business relationships
  • Providing superior financial returns to our investors